Name: a testing platform for durability studies of polymers and fiber-reinforced polymer composites under concurrent hygrothermo-mechanical stimuli
Uploaded: 2014-12-11T15:00:00.000+00:00
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Description: Watch this Scientific Journal Video about A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli at JoVE.com

作者感谢命运加西亚，小威费拉罗，埃里克·基罗斯和史蒂芬克恩（先进复合材料研究，工程和科学实验室），他们在设计和制造测试设置的帮助。肖恩·马龙，迈克尔·Akahori，大卫Kehlet（工程实验室制造）的承认了他们的建议，并在加工过程中的协助。支持美国国家科学基金会（协作补助CMMI-1265691和欧洲区域办事处的补充）和海军研究办公室（N00014-13-1-0604至A. Muliana，德州＆M大学（首席研究员）和V.拉萨波纳拉由项目总监拉贾帕克萨亚帕管理）的衷心赞赏。

1.装入标本<ol><li>提高罐的盖子并在侧部支撑搁（ 图4）。 </li><li>放置在U形螺栓的试验片，并确保横杆正在试样的中心接触。 </li><li>搁置在铝支撑悬挂在盖的检体的端部。样品的端部应具有5-10毫米的突出端。 </li><li>重复步骤1.2-1.4对所有将被测试的标本。 </li><li>取下盖子支持，下盖，并确保盖子落座于该储箱的唇。 </li><li>通过将权重应用到钢杆旁边的外滑轮应用所需的力。 </li></ol> 2.测量位移<ol><li>确保字符串电位线拉紧。 </li><li>使用数字万用表，测量电阻两端的电位的外销（ 图3）中，用黑色至引脚1和红至引脚3，并记录读数。 </li><li>转换电阻读入的位移读取通过计算校准因子（在这种情况下，1kΩ的对应一个64.895毫米位移）。 </li><li>重复步骤2.1-2.3为每个标本。 </li></ol> 3.权衡标本<ol><li>在开始称量过程中，记录位移数据和编制临时收容室充满在室温测试液，按ASTM D5229 31或相应的检测标准。 </li><li>从钢索的端部取出开槽权重。 </li><li>提高罐的盖子并在侧部支撑休息吧。 </li><li>取下样品，将其放入准备好的临时收容室。重复所有样品的这一步。 </li><li>取出试样并干燥它们单独使用微纤维布，以除去多余的液体。 </li><li>放置在试样上的高精确度的规模和记录数据Reading。 </li><li>重复步骤3.5-3.6为所有标本，然后按照协议第1步 。 </li></ol>

<ol>
	<li>Katnam, K. B., Da Silva, L. F. M., Young, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bonded+repair+of+composite+aircraft+structures:+A+review+of+scientific+challenges+and+opportunities.">Bonded repair of composite aircraft structures: A review of scientific challenges and opportunities.</a> Prog Aerosp Sci. 61, 26-42 (2013).</li><li>Hollaway, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+the+present+and+future+utilization+of+FRP+composites+in+the+civil+infrastructure+with+reference+to+their+important+in-service+properties.">A review of the present and future utilization of FRP composites in the civil infrastructure with reference to their important in-service properties.</a> Constr Build Mater. 24, 2419-2445 (2010).</li><li>Mouritz, A. P., Gellert, E., Burchill, P., Challis, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+advanced+composite+structures+for+naval+ships+and+submarines.">Review of advanced composite structures for naval ships and submarines.</a> Compos Struct. 53, 21-41 (2001).</li><li>Albanilla, M. A., Li, Y., Karbhari, V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Durability+characterization+of+wet+layup+graphite/epoxy+composites+used+in+external+strengthening.">Durability characterization of wet layup graphite/epoxy composites used in external strengthening.</a> Compos Part B-Eng. 37, 200-212 (2006).</li><li>Jedidi, J., Jacquemin, F., Vautrin, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accelerated+hygrothermal+cyclical+tests+for+carbon/epoxy+laminates.">Accelerated hygrothermal cyclical tests for carbon/epoxy laminates.</a> Compos. Part A &#8211;Appl. Sci. 37, 636-645 (2006).</li><li>Jones, L. C., Tsao, A. K., Topoleski, L. D. T., N, E. l. i. a. z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Orthopedic+Implant+Retrieval+and+Failure+Analysis.">Orthopedic Implant Retrieval and Failure Analysis.</a> Degradation of Implant Materials. , 393-447 (2012).</li><li>Gellert, E. P., Turley, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Seawater+immersion+ageing+of+glass-fibre+reinforced+polymer+laminates+for+marine+applications.">Seawater immersion ageing of glass-fibre reinforced polymer laminates for marine applications.</a> Compos. Part A &#8211;Appl. Sci. 30, 1259-1265 (1999).</li><li>Sugita, Y., Winkelmann, C., La Saponara, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+and+chemical+degradation+of+carbon/epoxy+lap+joints+for+aerospace+applications,+and+effects+on+their+mechanical+performance.">Environmental and chemical degradation of carbon/epoxy lap joints for aerospace applications, and effects on their mechanical performance.</a> Compos. Sci. Technol. 70, 829-839 (2010).</li><li>Campbell, R. A., Pickett, B. M., La Saponara, V., Dierdorf, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+Characterization+and+Flammability+of+Structural+Epoxy+and+Carbon/Epoxy+Composite+with+Environmental+and+Chemical+Degradation.">Thermal Characterization and Flammability of Structural Epoxy and Carbon/Epoxy Composite with Environmental and Chemical Degradation.</a> J. Adhes. Sci. Technol. 26, 889-910 (2012).</li><li>Landry, B., LaPlante, G., LeBlanc, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environmental+effects+on+mode+II+fatigue+delamination+growth+in+an+aerospace+grade+carbon/epoxy+composite.">Environmental effects on mode II fatigue delamination growth in an aerospace grade carbon/epoxy composite.</a> Compos. A-Appl. Sci. 43, 475-485 (2012).</li><li>Ferracane, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydroscopic+and+hydrolytic+effects+in+dental+polymer+networks.">Hydroscopic and hydrolytic effects in dental polymer networks.</a> Dent. Mater. 22, 211-222 (2006).</li><li>Mueller, Y., Tognini, R., Mayer, J., Virtanen, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anodized+titanium+and+stainless+steel+in+contact+with+CFRP:+An+electrochemical+approach+considering+galvanic+corrosion.">Anodized titanium and stainless steel in contact with CFRP: An electrochemical approach considering galvanic corrosion.</a> J. Biomed. Mater. Res. &#8211;A. 82, 936-946 (2007).</li><li>Bagley, E., Long, F. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-state+Sorption+and+Desorption+of+Organic+Vapors+in+Cellulose+Acetate.">Two-state Sorption and Desorption of Organic Vapors in Cellulose Acetate.</a> J. Am. Chem. Soc. 77, 2172-2178 (1955).</li><li>Shen, C. -. H., Springer, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moisture+Absorption+and+Desorption+of+Composite+Materials.">Moisture Absorption and Desorption of Composite Materials.</a> J. Compos Mater. 10, 2-20 (1976).</li><li>Zhou, J., Lucas, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hygrothermal+effects+of+epoxy+resin.+Part+I:+the+nature+of+water+in+epoxy.">Hygrothermal effects of epoxy resin. Part I: the nature of water in epoxy.</a> Polymer. 40, 5505-5512 (1999).</li><li>Abot, J. L., Yasmin, A., Daniel, I. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hygroscopic+Behavior+of+Woven+Carbon-Epoxy+Composites.">Hygroscopic Behavior of Woven Carbon-Epoxy Composites.</a> J. Reinf. Plast. Comp. 24, 195-207 (2005).</li><li>LaPlante, G., Ouriadov, A. V., Lee-Sullivan, P., Balcom, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anomalous+Moisture+Diffusion+in+an+Epoxy+Adhesive.">Anomalous Moisture Diffusion in an Epoxy Adhesive.</a> J. Appl. Polym. Sci. 109, 1350-1359 (2008).</li><li>Weitsman, Y. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anomalous+fluid+sorption+in+polymeric+composites+and+its+relation+to+fluid-induced+damage.">Anomalous fluid sorption in polymeric composites and its relation to fluid-induced damage.</a> Compos. Part A &#8211;Appl. Sci. 37, 617-623 (2006).</li><li>Karbhari, V. M., Ghosh, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+durability+evaluation+of+ambient+temperature+cured+externally+CFRP+and+GFRP+composiste+systems+for+repair+of+bridges.">Comparative durability evaluation of ambient temperature cured externally CFRP and GFRP composiste systems for repair of bridges.</a> Compos. Part A &#8211;Appl. Sci. 40, 1353-1363 (2009).</li><li>Neumann, S., Marom, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Free-volume+dependent+moisture+diffusion+under+stress+in+composite+materials.">Free-volume dependent moisture diffusion under stress in composite materials.</a> J. Mater. Sci. 21, 26-30 (1986).</li><li>Wan, Y. Z., Wang, Y. L., Huang, Y., He, B. M., Han, K. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hygrothermal+aging+behaviour+of+VARTMed+three-dimensional+braided+carbon-epoxy+composites+under+external+stresses.">Hygrothermal aging behaviour of VARTMed three-dimensional braided carbon-epoxy composites under external stresses.</a> Compos. Part A &#8211;Appl. Sci. 36, 1102-1109 (2005).</li><li>Helbling, C. S., Karbhari, V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+the+Sorption+and+Tensile+Response+of+Pultruded+E-Glass/Vinylester+Composites+Subjected+to+Hygrothermal+Exposure+and+Sustained.">Investigation of the Sorption and Tensile Response of Pultruded E-Glass/Vinylester Composites Subjected to Hygrothermal Exposure and Sustained.</a> J. Reinf. Plast. Comp. 27, 613-638 (2008).</li><li>Kasturiarachchi, K. A., Pritchard, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Water+absorption+of+glass/epoxy+laminates+under+bending+stresses.">Water absorption of glass/epoxy laminates under bending stresses.</a> Composites. 14, 244-250 (1983).</li><li>Abdel-Magid, B., Ziaee, S., Gass, K., Schneider, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+combined+effects+of+load,+moisture+and+temperature+on+the+properties+of+E-glass/epoxy+composites.">The combined effects of load, moisture and temperature on the properties of E-glass/epoxy composites.</a> Compos Struct. 71, 320-326 (2005).</li><li>Ellyin, F., Rohrbarcher, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Influence+of+Aqueous+Environment,+Temperature+and+Cyclic+Loading+on+Glass-Fibre/Epoxy+Composite+Laminates.">The Influence of Aqueous Environment, Temperature and Cyclic Loading on Glass-Fibre/Epoxy Composite Laminates.</a> J Reinf Plast Comp. 22, 615-636 (2003).</li><li>Earl, J. S., Dulieu-Barton, J. M., Shenoi, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+hygrothermal+ageing+effects+in+sandwich+construction+joints+using+thermoelastic+stress+analysis.">Determination of hygrothermal ageing effects in sandwich construction joints using thermoelastic stress analysis.</a> Compos Sci Technol. 63, 211-223 (2003).</li><li>Jeon, J., Muliana, A., La Saponara, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+stress+and+deformation+analyses+in+fiber+reinforced+polymer+composites+undergoing+heat+conduction+and+mechanical+loading.">Thermal stress and deformation analyses in fiber reinforced polymer composites undergoing heat conduction and mechanical loading.</a> Compos. Struct. 111, 31-44 (2014).</li><li>Muliana, A. H., Rajagopal, K. R., Wineman, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+class+of+quasi-linear+models+for+describing+the+non-linear+viscoelastic+response+of+materials.">A new class of quasi-linear models for describing the non-linear viscoelastic response of materials.</a> Acta Mech. 224, 2169-2183 (2013).</li><li>Joshi, N., Muliana, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deformation+in+Viscoelastic+Sandwich+Composites+Subject+to+Moisture+Diffusion.">Deformation in Viscoelastic Sandwich Composites Subject to Moisture Diffusion.</a> Compos. Struct. 92, 254-264 (2010).</li><li>Muliana, A. H., Sawant, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viscoelastic+Responses+of+Polymer+Composites+with+Temperature+and+Time+Dependent+Constituents.">Viscoelastic Responses of Polymer Composites with Temperature and Time Dependent Constituents.</a> Acta Mech. 204, 155-173 (2009).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+Test+Method+for+Moisture+Absorption+Properties+and+Equilibrium+Conditioning+of+Polymer.">Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer.</a> Matrix Composite Materials. ASTM International. , (2004).</li></ol>

The authors have nothing to disclose.

从所获得的数据，可以看出，并发测试场景并影响闭孔聚氨酯泡沫试样的耐久性。这可以通过在显著不同的位移（ 图5）和残余的负载比较失败干湿标本（ 图6）可以看出， 图7示出了样品的残余强度试验后的照片。还应当指出的是，虽然干标本的位移的24小时观测间隔内达到稳定状态，这些湿标本没有。因此，未来的测试将在较长的时间间隔进行，要么实现经调节的试样的稳态行为或建立这种稳态一个给定的测试时间内可能是不可能的（例如，如果材料的经验降解，导致失败）。 图6的盒状图</strong&gt;表明，残留的荷载的分配失败的湿标本是静态的不同和下部相对于用于干标本的情况。 这一结果的直接比较不能与文献，因为通过不同的作者选择的相对有限的公布的数据和不同的材料和负载型材制成。然而，与此夹具获得代表结果同意遵守盖勒特和特里7条，共经历了玻璃纤维增强样本"显著高于"蠕变变形的趋势。 该测试设备可以增加其鲁棒性和易用性得到改善。滑动架将在顶部框架的基部中加入支持以保持电位以更安全的方式。这将减少运动的可能性，因此，增加了读数的精确度。此外，电位将连接到小面包板到三针螺丝端子。这也将提高读数的精确度，因为这将消除需要触碰电位而进行测量。 计划进一步改进，以进一步提高该装置的灵活性。例如，一个新的盖子将被开发，以检测潜在的有害化学物质，当创建一个气密密封。这种变化将有可能导致的协议步骤1的变形例。浸没加热器也可以允许用于测试在升高的温度下加入。当测试一个盐溶液，磁力搅拌棒来代替昂贵的不锈钢浸没式加热器的考虑。这将需要一个变形例，为一个磁源的掺入该装置的基础。所得试验装置将提供如何并发测试影响聚合物和聚合物的耐久性的更广阔的画面在各种在职条件基复合材料。

聚合物和纤维增强聚合物（FRP）复合材料已通过各种工程结构，从飞机和飞船，舰艇，民用基础设施，（见Katnam 等 1，Hollaway 2，Mouritz 等人的例子评论第3号 ），汽车和火车，风力涡轮机叶片，以假肢和生物材料缝合线和植入物。这些材料的耐久性受复杂的服务方案，其可包括的组合）的热机械载荷， 例如 ，冷冻-解冻循环在民用基础设施4，亚音速/超音速飞行型材5穿在金属背聚乙烯6） ;二）的降解，由于环境和化学制剂， 例如 ，海水，除冰，用于航空航天和海军结构7-10中，聚甲基丙烯酸甲酯的牙科复合材料由于唾液降解11的液压流体;三）复杂的INTE材料在紧固或接合接头，异种材料之间例如 ，电偶腐蚀和剥离，ractions是否在碳/纤维补片修补在飞行器铝皮，或碳/ PEEK骨板由不锈钢12紧固。 有不幸的是有限的并发在职刺激对这些材料的长期耐久性的影响的知识。大多数聚合物可以被分类为粘弹性材料。机械载荷和环境条件显著影响聚合物的粘弹性响应。因此，可靠的模型，这些材料的长期行为应该能够把依赖于时间的响应耦合湿热，机械，化学刺激。反过来，这将提高设计的预测，安全性和基于状态的维护/更换协议。 有实验测试在湿热作用的大型文献体例如湿热扩散试验:如果样品的尺度允许，该材料的样品可以被定位在所希望的湿度和温度水平的腔室。将样品定期取出，以测量的时间在给定量的质量和/或体积的变化，从周向年10,13-17。在湿热试验之后可以机械测试， 即 ，剩余静/疲劳强度/断裂力学测试17-19，其中仅提供了有关湿热刺激对材料的机械反应的影响的信息。测试数据可以装配不同的复杂性，从简单的菲克扩散模型，包括依赖于浓度，压力，温度，可逆物理老化/增塑和不可逆的化学反应的扩散模型。这个实验的输出可以在结构分析得到进一步整合。 很少有作家已经解决了同时HY的影响grothermal和机械刺激。在这些研究的FRP复合材料，诺依曼和Garom 20浸入强调和无应力样本在蒸馏水中。应力被通过定位压缩不锈钢弹簧内的试样施加，通过使用不同的弹簧刚度和压缩载荷调整负载。类似的过程被报道万等人 21。何浦林和Karbhari 22所采用的弯曲夹具环境室用于不同的相对湿度的百分比（相对湿度％）和温度水平内。所述预调节样品进行到给定的弯曲应变的水平，对应于静态极限拉伸应变为该复合物的百分比。 Kasturiarachchi和普里查德23制备一个不锈钢4点弯曲夹具（每个试样1），将其放置在一个架子上的一个大的玻璃干燥器。干燥器被部分地填充有蒸馏水，不得不小的泄漏，防止BUildup的压力，并放置在湿度室中于95％相对湿度。盖勒特和特里7查处海洋级玻璃钢复合标本进行联合下蠕变负荷和100％RH其耐用性。他们的样品被装在四点弯曲以恒定载荷等于失败静态挠曲负荷的20％，而完全浸没在海水中。蠕变挠度是通过使用光束在中央的横截面，并在玻璃板的外表面之间的厚度计周期性地获得（据推断，这种测量是在室的外部执行）。阿卜杜勒-马吉德等人 24放置的玻璃/环氧样品其经NASA兰利提供，如被装在沿纤维方向张力的标本，在最终的轴向负荷为20％的殷钢环境夹具。 Ellyin和Rohrbarcher 25跑湿热测试为多达140天，然后测试在疲劳试样的液压试验机上。试样s被包裹在湿干酪布连接到管和供水。伯爵等人 26位的装载和固定在一个大环境室（5.5 立方米 ）的标本。 因为在许多实验研究讨论的，环境条件会影响聚合物&#39;的机械性能和响应。一些有限的实验也表明，机械应力/应变的存在影响的扩散过程中的聚合物。因此，为了促进理解上的下机械和非机械效应的聚合物基材料的整体性能，有必要对并发测试。 有在本文中讨论的测试平台的设计背后的几个目标。首先，该平台是实验装置在不同类型的FRP夹层复合材料的风力涡轮机的hygrothermo力学行为的多年研究的一部分第二海军工程应用。试验数据被用来校正在所述粘弹性构方程为聚合物复合材料的参数。本构模型的基础上发展，多年来深受Muliana和合作者27-30工作。第二个目标是为具有低成本和用户友好的测试平台，例如一个可以很容易地重新定位在一个实验室（ 例如 ，以一个尺度为质量测量，或对流体的源， 例如 ，一个未来从水龙头，一个通风柜或易燃柜）。第三个目标是建立一个测试平台，它能够抵抗许多化学品在服务常用的（特别是液压流体，除冰，清洗剂用于航空航天应用8-10），从而标本可浸入这样的化学品，以及其耐用性可以进行评估。 腔室（ 图1），用高密度polyethyle构造NE，它具有高耐化学性。如上所述，预计今后的工作将包括浸在液压流体的复合材料的hygrothermo机械调查，除冰，清洁溶剂。自热调节是测试的一个组成部分，膨胀聚苯乙烯泡沫体适合围绕罐的侧面和固定就位通过带与钢框架本身，以防止与环境进行热交换。 腔室（ 图2）的盖是从透明，9.525毫米厚的聚碳酸酯制，使用户能够在测试过程中观察试样，而不会干扰测试。该盖由铝的T杆，这是加工成下在罐的侧面悬垂括号滑动地固定在适当位置。 弯曲在标本是由三个铝块，其从盖垂下，并且通过盖子槽被紧固颁布。这三个模块允许最多四个Specimens到一次进行测试，而在盖的槽允许根据试样的长度的块的间距进行调整。每块圆在接触边缘直径12.7毫米，在坚持以ASTM标准D790-10。试样被定位下方的两个3块，与施加在其中心以诱导弯曲的向上的力（ 图1-2）。 该装置在设计时最大的多功能性和易用性，使用的初衷。脚轮与41.275毫米直径被紧固的室，用于移动性目的的下方。以上这些，该罐是由与金属丝网底梁和横梁用于支撑一个焊接钢架支撑。角库存衬垫为外槽的角落被制造以保持绝缘层被粉碎的开销重量和位移计（串锅装置，稍后讨论）。在上面，角度的股票再次被用于取景。滑轮和字符串电位系统measu重中跨偏转被安装在4钢，方管拱（ 图3）。该中心两个拱出这四个携带串电位器和可调占样本的多功能性。字符串电位器均采用扭力弹簧构造和电位器（如可伸缩的关键挂链上找到）与三管齐下电子输出。滑轮被对准并安装用于与钢缆从由试样的刚性连接到一个挂杆在腔，用于调节体重的应用的侧运行使用。 的载荷被施加到使用一系列电缆，滑轮，联系和螺栓试样。首先，将试样放入所述U形螺栓，使得10毫米横杆被接触的跨度的中间。一个9.525毫米直径钢杆吊环螺栓的每一端，然后连接到U型螺栓。通过腔室的盖这种钢连接传递。钢索和芳纶吨hread附着到U形螺栓对面有眼螺栓。这允许从字符串电位的芳纶线程从一个刚性点读取数据。钢缆继续向上，并越过两个滑轮，使负载在罐的外周施用。缆线随后连接到一个9.525毫米直径钢杆用作开槽重量衣架。此吊架提供其中开槽权重可在为了应用所需的负荷被设置的地方。

<table><tbody><tr><td>Aluminum 6061 rectangular bars</td><td>McMaster-Carr, USA</td><td>8975K268, 1668T72, 7062T17,&amp;nbsp;</td><td>Part of testing platform</td></tr><tr><td>Aluminum 6061 90&amp;deg; angles</td><td>McMaster-Carr, USA</td><td>8982K91, 8982K14&amp;nbsp;</td><td>Part of testing platform</td></tr><tr><td>440C stainless steel</td><td>McMaster-Carr, USA</td><td>6253K52</td><td>Part of testing platform</td></tr><tr><td>High-density polyethylene sheets</td><td>Tap Plastics, USA</td><td>N/A (0.236 in. thick x 10.75 in. wide x 16.75 in. long)</td><td>Part of testing platform</td></tr><tr><td>High-density polyethylene sheets</td><td>Tap Plastics, USA</td><td>N/A (0.354 in. thick x 6 in. wide x 10 in. long)</td><td>Part of testing platform</td></tr><tr><td>High-density polyethylene sheets</td><td>Tap Plastics, USA</td><td>N/A (0.354 in. thick x 6 in. wide x 16.75 in. long)</td><td>Part of testing platform</td></tr><tr><td>Polycarbonate sheets</td><td>Tap Plastics, USA</td><td>N/A (0.375 in thick, 11.5 in. wide, 17.5 in long)</td><td>Part of testing platform</td></tr><tr><td>Expanded polystyrene foam</td><td>Home Depot</td><td>Model # 310880 Internet # 202532855</td><td>Part of testing platform</td></tr><tr><td>Galvanized steel rope</td><td>McMaster-Carr, USA</td><td>3498T63</td><td>Part of testing platform</td></tr><tr><td>Steel eye bolt</td><td>McMaster-Carr, USA</td><td>3013T341</td><td>Part of testing platform</td></tr><tr><td>Low-carbon steel 90&amp;deg; angle</td><td>McMaster-Carr, USA</td><td>9017K444&amp;nbsp;</td><td>Part of testing platform</td></tr><tr><td>Low-carbon steel rods</td><td>McMaster-Carr, USA</td><td>8920K84, 8920K75, 8920K231, 8920K135, 8920K84&amp;nbsp;&amp;nbsp;&amp;nbsp;</td><td>Part of testing platform</td></tr><tr><td>Low-carbon steel tubes</td><td>McMaster-Carr, USA</td><td>6527K314, 8910K394, 8910K395, 8920K94&amp;nbsp;&amp;nbsp;</td><td>Part of testing platform</td></tr><tr><td>304 stainless steel U-bolt</td><td>McMaster-Carr, USA</td><td>8896T104</td><td>Part of testing platform</td></tr><tr><td>Steel pulley</td><td>McMaster-Carr, USA</td><td>3099T34</td><td>Part of testing platform</td></tr><tr><td>1008 carbon steel sheets</td><td>McMaster-Carr, USA</td><td>9302T113</td><td>Part of testing platform</td></tr><tr><td>Light duty swivel casters</td><td>Harbor Freight, USA</td><td>41519</td><td>Part of testing platform</td></tr><tr><td>100-lbf Vinyl Weight Set</td><td>Overstock.com</td><td>11767059</td><td>Part of testing platform</td></tr><tr><td>Closed-cell polyurethane foam</td><td>General Plastics, USA</td><td>FR-3704</td><td>Testing samples</td></tr><tr><td>Deionized water</td><td>Faucet, PurLab filtering system</td><td>N/A</td><td>Conditioning fluid of tank</td></tr><tr><td>Torsional spring</td><td>Retractable Key Clip, Ebay, USA</td><td>Lot 10</td><td>Used to build string potentiometer</td></tr><tr><td>Kevlar thread</td><td>Cabela&amp;rsquo;s</td><td>IK-321909</td><td>Used to build string potentiometer</td></tr><tr><td>10 kOhm potentiometer</td><td>Ebay, USA</td><td>3590S-2-103L</td><td>Used to build string potentiometer</td></tr><tr><td>Digital multimeter</td><td>Harbor Freight, USA</td><td>98674</td><td>Used to take resistance measurements of string potentiometer</td></tr></tbody></table>

a testing platform for durability studies of polymers and fiber-reinforced polymer composites under concurrent hygrothermo-mechanical stimuli

服务条件下的聚合物和纤维增强聚合物复合材料的耐用性是其强大的设计和基于状态的维护需要解决的一个重要方面。这些材料是通过在一个宽范围的工程应用中，从飞机和船舶的结构，对桥梁，风力涡轮机叶片，生物材料和生物医学植入物。聚合物是粘弹性材料，并且它们的响应可以是高度非线性的，从而使之具有挑战性，预测和监测其使用性能。该实验室规模的试验平台，此呈现助攻并发的机械负荷和对这些材料的环境条件的影响的调查。该平台被设计成低成本和用户友好。其耐化学腐蚀的材料，使该平台适用于化学降解由于在职接触液体的研究。实验的一个例子在RT上的闭孔聚氨酯进行泡沫样品装载有对应于它们的最后的静态和干负荷〜50％的重量。结果表明，该检测装置是适合于这些研究。结果也显示并发载荷下，聚合物的较大的脆弱性，基于所述更高的中点位移和较低的残余破坏载荷。建议向测试设备的额外改进而成。

测试仪器已成功举办标本浸在液体下三点弯曲。以合理的精度，标本可以加载并使用从电位为中点挠度变化准确读数测试。的电阻的变化可以被记录到4显著数字，导致0.1微米量级的位移分辨率。 Hygrothermo机械试验在RT上两组四个试样的闭孔聚氨酯泡沫塑料进行的，用标称尺寸215毫米长度×24毫米宽×18毫米的厚度。一组是在干燥条件下）中的空气腔室，目的是作为试验，油箱内，以及b）在〜50％RH（试验在实验室中发生在六月底环境相对湿度位于热干燥的加利福尼亚州北部中央谷地，在美国）。这第一样本组在此表示为"干标本"。第二组样品是在罐测试，而完全浸没在去离子水（100％的相对湿度，在此表示为"湿标本&#39;）。标本装入悬挂重物下静态干燥条件大致等于其最终负载的50％，从而导致（1.780±0.116）公斤。每个吊重的应用了几秒钟，以实现准静态加载条件。据预计，该泡沫将具有非线性粘弹行为，但它不知道先验如何并发刺激会降低泡沫的耐久性相对于该干燥样品。 在数字万用表的电阻测量是对每个样品，在约15分钟的间隔为第6小时的测试。测量是一个额外的18小时后，再次服用。由此看来，在跨中挠度的变化进行了跟踪。根据收集到的数据，24小时后的位移为干标本为（2.141±0.371）毫米，而位移的湿标本是显著更高，等于（14.41±3.62）毫米（ 图5，表1）。 以下各试运行中，样品然后通过装载它们，直到失败测试剩余强度。湿标本中发现有残留失败负载等于（2.970±0.246）公斤，相比的残余破坏载荷（3.623±0.0967）公斤的干试样，（图6，表2）。分辨率为剩余破坏载荷测量为±0.194千克。 <img alt="图1" src="/files/ftp_upload/52464/52464fig1highres.jpg" /> 图1的测试装置的主要部件的概述。A.高密度聚乙烯罐中。 B.发泡聚苯乙烯泡沫绝缘材料。 C.开槽聚碳酸酯盖子。 D.铝制t酒吧和悬支架。 E.三点弯曲苏pports。 F.底框。 G.角度间隔。 H.顶部框架。 I.字符串电位器组件。 J.下装载组件。 K.开槽重量和衣架。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52464/52464fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/52464/52464fig2highres.jpg" /> 图盖2.详细视图。 A.高密度聚乙烯罐。C.开槽聚碳酸酯盖子。 D.铝合金T形杆悬支架。 E.三点弯曲支撑。 J.下装载组件。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52464/52464fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/52464/52464fig3highres.jpg" /> 图3。 </str翁&gt; 测试设备的字符串电位器装配。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52464/52464fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/52464/52464fig4highres.jpg" /> 图4.盖支持的测试设备。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52464/52464fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" fo:content-width="6in" src="/files/ftp_upload/52464/52464fig5highres.jpg" width="600" /> 图5.中跨位移随时间的变化，干，湿标本。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52464/52464fig5large.jpg" target="_blank">普莱斯</a>e单击此处查看该图的放大版本。 <img alt="图6" fo:content-width="4in" src="/files/ftp_upload/52464/52464fig6highres.jpg" width="400" /> 图6.盒地块剩余负载故障，干，湿标本，展示湿标本的大漏洞。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52464/52464fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图7" fo:content-width="6in" src="/files/ftp_upload/52464/52464fig7highres.jpg" width="600" /> 图7.图片泡沫试样后的残余的弯曲强度测试:（A）和（B）的干试样，（C）和（D）的湿标本。标称试样宽度为24毫米。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52464/52464fig7highres.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td> 从小时 开始 </td><td> 变化的位移（毫米）的，标本1 </td><td> 变化的位移（毫米）的，标本2 </td><td> 变化的位移（毫米）的，3标本 </td><td> 变化的位移（毫米）的，标本4 </td></tr><tr><td> 0.000 </td><td> 0.000 </td><td> 0.000 </td><td> 0.000 </td><td> 0.000 </td></tr><tr><td> 0.230 </td><td> 0.454 </td><td> 0.130 </td><td> 1.298 </td><td> 0.195 </td></tr><tr><td> 0.730 </td><td> 0.714 </td><td> 2.141 </td><td> 1.298 </td><td> 1.817 </td></tr><tr><td> 0.980 </td><td> 0.779 </td><td> 2.141 </td><td> 1.298 </td><td> 1.817 </td></tr><tr><td> 1.310 </td><td> 0.779 </td><td> 2.076 </td><td> 1.298 </td><td> 1.817 </td></tr><tr><td> 1.810 </td><td> 1.038 </td><td> 2.141 </td><td> 1.947 </td><td> 1.817 </td></tr><tr><td> 2.010 </td><td> 0.973 </td><td> 2.206 </td><td> 1.947 </td><td> 1.817 </td></tr><tr><td> 2.350 </td><td> 1.363 </td><td> 2.076 </td><td> 1.947 </td><td> 1.882 </td></tr><tr><td> 2.610 </td><td> 1.363 </td><td> 2.076 </td><td> 1.947 </td><td> 1.752 </td></tr><tr><td> 2.730 </td><td> 1.428 </td><td> 2.076 </td><td> 1.947 </td><td> 1.752 </td></tr><tr><td> 3.230 </td><td> 1.557 </td><td> 2.076 </td><td> 2.596 </td><td> 1.817 </td></tr><tr><td> 3.480 </td><td> 1.298 </td><td> 2.076 </td><td> 1.947 </td><td> 1.947 </td></tr><tr><td> 3.810 </td><td> 1.622 </td><td> 2.076 </td><td> 2.596 </td><td> 1.817 </td></tr><tr><td> 4.010 </td><td> 1.622 </td><td> 2.076 </td><td> 2.596 </td><td> 1.817 </td></tr><tr><td> 4.230 </td><td> 1.557 </td><td> 2.076 </td><td> 2.596 </td><td> 2.012 </td></tr><tr><td> 4.480 </td><td> 1.557 </td><td> 2.076 </td><td> 2.596 </td><td> 2.012 </td></tr><tr><td> 4.730 </td><td> 1.622 </td><td> 2.076 </td><td> 2.596 </td><td> 2.012 </td></tr><tr><td> 4.980 </td><td> 1.752 </td><td> 2.141 </td><td> 2.596 </td><td> 1.947 </td></tr><tr><td> 5.230 </td><td> 1.752 </td><td> 2.076 </td><td> 3.244 </td><td> 1.947 </td></tr><tr><td> 5.510 </td><td> 1.687 </td><td> 2.141 </td><td> 2.596 </td><td> 2.012 </td></tr><tr><td> 5.780 </td><td> 1.557 </td><td> 2.076 </td><td> 2.596 </td><td> 1.882 </td></tr><tr><td> 5.980 </td><td> 1.687 </td><td> 2.076 </td><td> 2.596 </td><td> 1.947 </td></tr><tr><td> 6.310 </td><td> 1.622 </td><td> 2.141 </td><td> 2.596 </td><td> 1.882 </td></tr><tr><td>6.480 </td><td> 1.622 </td><td> 2.206 </td><td> 2.596 </td><td> 2.012 </td></tr><tr><td> 23.550 </td><td> 1.882 </td><td> 2.206 </td><td> 2.596 </td><td> 1.882 </td></tr><tr><td> 23.967 </td><td> 1.752 </td><td> 2.271 </td><td> 2.596 </td><td> 1.947 </td></tr></tbody></table> 表1.位移与泡沫样品在环境相对湿度（干样品）的时间 。 <table border="0" cellpadding="0" cellspacing="0" fo:keep-together.within-page="always"><tbody><tr><td> 从小时 开始 </td><td> 变化的位移（毫米）的，标本1 </td><td> 变化的位移（毫米）的，标本2 </td><td> 变化的位移（毫米）的，3标本 </td><td> 变化的位移（毫米）的，标本4 </td></tr><tr><td> 0.000 </td><td> 0.000 </td><td> 0.000 </td><td> 0.000 </td><td> 0.000 </tD&gt; </tr><tr><td> 0.303 </td><td> 3.245 </td><td> 0.000 </td><td> 1.298 </td><td> 0.000 </td></tr><tr><td> 0.653 </td><td> 3.439 </td><td> 0.195 </td><td> 2.596 </td><td> 0.000 </td></tr><tr><td> 0.903 </td><td> 4.932 </td><td> 1.168 </td><td> 3.894 </td><td> 1.168 </td></tr><tr><td> 1.163 </td><td> 4.932 </td><td> 1.168 </td><td> 3.245 </td><td> 1.233 </td></tr><tr><td> 1.433 </td><td> 6.295 </td><td> 2.206 </td><td> 4.543 </td><td> 2.012 </td></tr><tr><td> 1.703 </td><td> 6.360 </td><td> 2.466 </td><td> 4.543 </td><td> 2.142 </td></tr><tr><td> 2.013 </td><td> 7.074 </td><td> 2.855 </td><td> 5.192 </td><td> 2.077 </td></tr><tr><td> 2.253 </td><td> 7.203 </td><td> 2.790 </td><td> 5.192 </td><td> 2.077 </td></tr><tr><td> 2.763 </td><td> 7.917 </td><td> 3.310 </td><td> 5.841 </td><td> 3.180 </td></tr><tr><td> 3.013 </td><td> 7.917 </td><td> 3.634 </td><td> 5.841 </td><td> 3.180 </td></tr><tr><td> 3.283 </td><td> 8.047 </td><td> 4.413 </td><td> 5.841 </td><td> 3.180 </td></tr><tr><td> 3.513 </td><td> 7.917 </td><td> 4.153 </td><td> 5.841 </td><td> 3.180 </td></tr><tr><td> 3.753 </td><td> 7.917 </td><td> 3.699 </td><td> 6.489 </td><td> 3.245 </td></tr><tr><td> 4.013 </td><td> 9.734 </td><td> 5.192 </td><td> 7.787 </td><td> 4.478 </td></tr><tr><td> 4.253 </td><td> 10.448 </td><td> 4.802 </td><td> 8.436 </td><td> 4.608 </td></tr><tr><td> 4.513 </td><td> 10.448 </td><td> 4.802 </td><td> 8.436 </td><td> 4.478 </td></tr><tr><td> 4.783 </td><td> 10.448 </td><td> 4.802 </td><td> 8.436 </td><td> 4.478 </td></tr><tr><td> 5.013 </td><td> 10.448 </td><td> 5.127 </td><td> 8.436 </td><td> 4.737 </td></tr><tr><td> 5.313 </td><td> 10.383 </td><td> 4.737 </td><td> 8.436 </td><td> 4.608 </tD&gt; </tr><tr><td> 5.513 </td><td> 11.421 </td><td> 5.711 </td><td> 9.085 </td><td> 5.581 </td></tr><tr><td> 5.753 </td><td> 11.421 </td><td> 56.46 </td><td> 9.085 </td><td> 5.711 </td></tr><tr><td> 6.033 </td><td> 11.551 </td><td> 5.776 </td><td> 9.085 </td><td> 5.516 </td></tr><tr><td> 6.333 </td><td> 11.486 </td><td> 6.035 </td><td> 9.085 </td><td> 5.581 </td></tr><tr><td> 6.503 </td><td> 11.551 </td><td> 6.360 </td><td> 9.734 </td><td> 6.035 </td></tr><tr><td> 23.300 </td><td> 16.937 </td><td> 10.383 </td><td> 14.277 </td><td> 9.734 </td></tr><tr><td> 23.650 </td><td> 17.067 </td><td> 10.318 </td><td> 15.575 </td><td> 9.734 </td></tr><tr><td> 23.983 </td><td> 17.002 </td><td> 10.253 </td><td> 14.277 </td><td> 10.383 </td></tr><tr><td> 24.250 </td><td> 17.262 </td><td> 10.253 </td><td> 14.926 </td><td> 9.994 </td></tr><tr><td> 24.983 </TD&gt; <td> 18.625 </td><td> 11.486 </td><td> 16.224 </td><td> 11.292 </td></tr></tbody></table> 表2.排量与泡沫标本在100％RH（湿标本）的时间 。

Watch this Scientific Journal Video about A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli at JoVE.com

A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli

The durability of polymers and fiber-reinforced polymer composites in service is a critical aspect for their designs and condition-based maintenance. We present a novel low-cost laboratory testing platform for the investigation of the influence of concurrent mechanical and environmental loadings, and may help design more efficient yet safer composite structures.

一个测试平台为聚合物的耐久性研究，并在同期Hygrothermo机械刺激纤维增强聚合物复合材料

The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs ...

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13.7K 次观看.  University of California, Davis. The durability of polymers and fiber-reinforced polymer composites in service is a critical aspect for their designs and condition-based maintenance. We present a novel low-cost laboratory testing platform for the investigation of the influence of concurrent mechanical and environmental loadings, and may help design more efficient yet safer composite structures.

视频: A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli

Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addition reaction. Strain-to-failure and glass transition behavior were investigated as a function of crosslinking monomer, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). An example non-stoichiometric system of 15 mol% PETMP thiol groups and an excess of 15 mol% acrylate groups was used to demonstrate the robust nature of the material. The LCE formed an aligned and transparent monodomain when stretched, with a maximum failure strain over 600%. Stretched LCE samples were able to demonstrate both stress-driven thermal actuation when held under a constant bias stress or the shape-memory effect when stretched and unloaded. A permanently programmed monodomain was achieved via a second-stage photopolymerization reaction of the excess acrylate groups when the sample was in the stretched state. LCE samples were photo-cured and programmed at 100%, 200%, 300%, and 400% strain, with all samples demonstrating over 90% shape fixity when unloaded. The magnitude of total stress-free actuation increased from 35% to 115% with increased programming strain. Overall, the two-stage TAMAP methodology is presented as a powerful tool to prepare main-chain LCE systems and explore structure-property-performance relationships in these fascinating stimuli-sensitive materials.

A novel methodology is presented to synthesize and program main-chain liquid-crystalline elastomers using commercially available starting monomers. A wide range of thermomechanical properties was tailored by adjusting the amount of crosslinker, while the actuation performance was dependent on the amount of applied strain during programming.

的可编程主链液晶性弹性体用双级硫醇丙烯酸酯反应合成

This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline ...

科研

化学

Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

Implantable microdevices are gaining significant attention for several biomedical applications1-4. Such devices have been made from a range of materials, each offering its own advantages and shortcomings5,6. Most prominently, due to the microscale device dimensions, a high modulus is required to facilitate implantation into living tissue. Conversely, the stiffness of the device should match the surrounding tissue to minimize induced local strain7-9. Therefore, we recently developed a new class of bio-inspired materials to meet these requirements by responding to environmental stimuli with a change in mechanical properties10-14. Specifically, our poly(vinyl acetate)-based nanocomposite (PVAc-NC) displays a reduction in stiffness when exposed to water and elevated temperatures (e.g. body temperature). Unfortunately, few methods exist to quantify the stiffness of materials in vivo15, and mechanical testing outside of the physiological environment often requires large samples inappropriate for implantation. Further, stimuli-responsive materials may quickly recover their initial stiffness after explantation. Therefore, we have developed a method by which the mechanical properties of implanted microsamples can be measured ex vivo, with simulated physiological conditions maintained using moisture and temperature control13,16,17. 
To this end, a custom microtensile tester was designed to accommodate microscale samples13,17 with widely-varying Young's moduli (range of 10 MPa to 5 GPa). As our interests are in the application of PVAc-NC as a biologically-adaptable neural probe substrate, a tool capable of mechanical characterization of samples at the microscale was necessary. This tool was adapted to provide humidity and temperature control, which minimized sample drying and cooling17. As a result, the mechanical characteristics of the explanted sample closely reflect those of the sample just prior to explantation.
The overall goal of this method is to quantitatively assess the in vivo mechanical properties, specifically the Young's modulus, of stimuli-responsive, mechanically-adaptive polymer-based materials. This is accomplished by first establishing the environmental conditions that will minimize a change in sample mechanical properties after explantation without contributing to a reduction in stiffness independent of that resulting from implantation. Samples are then prepared for implantation, handling, and testing (Figure 1A). Each sample is implanted into the cerebral cortex of rats, which is represented here as an explanted rat brain, for a specified duration (Figure 1B). At this point, the sample is explanted and immediately loaded into the microtensile tester, and then subjected to tensile testing (Figure 1C). Subsequent data analysis provides insight into the mechanical behavior of these innovative materials in the environment of the cerebral cortex.

Environmentally-controlled Microtensile Testing of Mechanically-adaptive Polymer Nanocomposites for ex vivo Characterization

A method is discussed by which the in vivo mechanical behavior of stimuli-responsive materials is monitored as a function of time. Samples are tested ex vivo using a microtensile tester with environmental controls to simulate the physiological environment. This work further promotes understanding the in vivo behavior of our material.

环境控制机械自适应聚合物纳米复合材料的微拉伸测试<em&gt;体外</em&gt;表征

Implantable microdevices are gaining significant attention for several biomedical applications1-4. Such devices have been made from a range of materials, ...

生物工程

In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure

High pressure hydrogen gas is known to adversely affect metallic components of compressors, valves, hoses, and actuators. However, relatively little is known about the effects of high pressure hydrogen on the polymer sealing and barrier materials also found within these components. More study is required in order to determine the compatibility of common polymer materials found in the components of the hydrogen fuel delivery infrastructure with high pressure hydrogen. As a result, it is important to consider the changes in physical properties such as friction and wear in situ while the polymer is exposed to high pressure hydrogen. In this protocol, we present a method for testing the friction and wear properties of ethylene propylene diene monomer (EPDM) elastomer samples in a 28 MPa high pressure hydrogen environment using a custom-built in situ pin-on-flat linear reciprocating tribometer. Representative results from this testing are presented which indicate that the coefficient of friction between the EPDM sample coupon and steel counter surface is increased in high pressure hydrogen as compared to the coefficient of friction similarly measured in ambient air.

In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure

A test methodology for quantifying tribological properties of polymers used in hydrogen infrastructure service is demonstrated and characteristic results for a common elastomer are discussed.

就地氢气输送基础设施用普通高分子材料的高压氢摩擦学试验

High pressure hydrogen gas is known to adversely affect metallic components of compressors, valves, hoses, and actuators. However, relatively little is ...

工程学

The Effect of Construction and Demolition Waste Plastic Fractions on Wood-Polymer Composite Properties

Construction and demolition waste (CDW), including valuable materials such as plastics, have a remarkable influence on the waste sector. In order for plastic materials to be re-utilized, they must be identified and separated according to their polymer composition. In this study, the identification of these materials was performed using near-infrared spectroscopy (NIR), which identified material based on their physical-chemical properties. Advantages of the NIR method are a low environmental impact and rapid measurement (within a few seconds) in the spectral range of 1600-2400 nm without special sample preparation. Limitations include its inability to analyze dark materials. The identified polymers were utilized as a component for wood-polymer composite (WPC) that consists of a polymer matrix, low cost fillers, and additives. The components were first compounded with an agglomeration apparatus, followed by production by extrusion. In the agglomeration process, the aim was to compound all materials to produce uniformly distributed and granulated materials as pellets. During the agglomeration process, the polymer (matrix) was melted and fillers and other additives were then mixed into the melted polymer, being ready for the extrusion process. In the extrusion method, heat and shear forces were applied to a material within the barrel of a conical counter-rotating twin-screw type extruder, which reduces the risk of burning the materials and lower shear mixing. The heated and sheared mixture was then conveyed through a die to give the product the desired shape. The above-described protocol proved the potential for re-utilization of CDW materials. Functional properties must be verified according to the standardized tests, such as flexural, tensile, and impact strength tests for the material.

Secondary material streams have been shown to include potential raw materials for production. Presented here is a protocol in which CDW-plastic waste as a raw material is identified, followed by various processing steps (agglomeration, extrusion). As a result, a composite material was produced, and mechanical properties were analyzed.

建筑与拆迁废塑料馏分对木聚合物复合性能的影响

Construction and demolition waste (CDW), including valuable materials such as plastics, have a remarkable influence on the waste sector. In order for ...

环境科学

Ultrasonic Fatigue Testing in the Tension-Compression Mode

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on exposing the specimen to longitudinal vibrations on its resonance frequency close to 20 kHz. With use of this method, it is possible to significantly decrease the time required for the test, when compared to conventional testing devices usually working at frequencies under 200 Hz. It is also used to simulate loading of material during operation in high speed conditions, such as those experienced by components of jet engines or car turbo pumps. It is necessary to operate only in the high and ultra-high cycle region, due to the possibility of extremely high deformation rates, which can have a significant influence on the test results. Specimen shape and dimensions have to be carefully selected and calculated to fulfill the resonance condition of the ultrasonic system; thus, it is not possible to test the full components or specimens of arbitrary shape. Before each test, it is necessary to harmonize the specimen with the frequency of the ultrasonic system to compensate for deviations of the real shape from the ideal one. It is not possible to run a test until a total fracture of the specimen, since the test is automatically terminated after initiation and propagation of the crack to a certain length, when the stiffness of the system changes enough to shift the system out of the resonance frequency. This manuscript describes the process of evaluation of materials' fatigue properties at high-frequency ultrasonic fatigue loading with use of mechanical resonance at a frequency close to 20 kHz. The protocol includes a detailed description of all steps required for a correct test, including specimen design, stress calculation, harmonizing with the resonance frequency, performing the test, and final static fracture.

A protocol for ultrasonic fatigue testing in the high and ultra-high cycle region in axial tension-compression loading mode.

拉伸压缩模式下的超声疲劳试验

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on ...

Disentangling High Strength Copolymer Aramid Fibers to Enable the Determination of Their Mechanical Properties

Traditionally, soft body armor has been made from poly(p-phenylene terephthalamide) (PPTA) and ultra-high molecular weight polyethylene. However, to diversify the fiber choices in the United States body armor market, copolymer fibers based on the combination of 5-amino-2-(p-aminophenyl) benzimidazole (PBIA) and the more conventional PPTA were introduced. Little is known regarding the long-term stability of these fibers, but as condensation polymers, they are expected to have potential sensitivity to moisture and humidity. Therefore, characterizing the strength of the materials and understanding their vulnerability to environmental conditions is important for evaluating their use lifetime in safety applications. Ballistic resistance and other critical structural properties of these fibers are predicated on their strength. To accurately determine the strength of the individual fibers, it is necessary to disentangle them from the yarn without introducing any damage. Three aramid-based copolymer fibers were selected for the study. The fibers were washed with acetone followed by methanol to remove an organic coating that held the individual fibers in each yarn bundle together. This coating makes it difficult to separate single fibers from the yarn bundle for mechanical testing without damaging the fibers and affecting their strength. After washing, fourier transform infrared (FTIR) spectroscopy was performed on both washed and unwashed samples and the results were compared. This experiment has shown that there are no significant variations in the spectra of poly(p-phenylene-benzimidazole-terephthalamide-co-p-phenylene terephthalamide) (PBIA-co-PPTA1) and PBIA-co-PPTA3 after washing, and only a small variation in intensity for PBIA. This indicates that the acetone and methanol rinses are not adversely affecting the fibers and causing chemical degradation. Additionally, single fiber tensile testing was performed on the washed fibers to characterize their initial tensile strength and strain to failure, and compare those to other reported values. Iterative procedural development was necessary to find a successful method for performing tensile testing on these fibers.

The primary goal of the study is to develop a protocol to prepare consistent specimens for accurate mechanical testing of high strength copolymer aramid fibers, by removing a coating and disentangling the individual fiber strands without introducing significant chemical or physical degradation.

解析高强共聚物芳纶纤维使其力学性能的测定

Traditionally, soft body armor has been made from poly(p-phenylene terephthalamide) (PPTA) and ultra-high molecular weight polyethylene. However, to ...

Cutting Procedures, Tensile Testing, and Ageing of Flexible Unidirectional Composite Laminates

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin polymer films. The armor is constructed by stacking the unidirectional layers in different orientations. To date, only very preliminary work has been performed to characterize the ageing of the binder resins used in unidirectional laminates and the effects on their performance. For example, during the development of the conditioning protocol used in the National Institute of Justice Standard-0101.06, UD laminates showed visual signs of delamination and reductions in V50, which is the velocity at which half of the projectiles are expected to perforate the armor, after ageing. A better understanding of the material property changes in UD laminates is necessary to comprehend the long-term performance of armors constructed from these materials. There are no current standards recommended for mechanically interrogating unidirectional (UD) laminate materials. This study explores methods and best practices for accurately testing the mechanical properties of these materials and proposes a new test methodology for these materials. Best practices for ageing these materials are also described.

The goal of the study was to develop protocols to prepare consistent specimens for accurate mechanical testing of high-strength aramid or ultra-high-molar-mass polyethylene-based flexible unidirectional composite laminate materials and to describe protocols for performing artificial ageing on these materials.

柔性单向复合层压板的切割程序、拉伸测试和老化

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, ...

Artificial Thermal Ageing of Polyester Reinforced and Polyvinyl Chloride Coated Technical Fabric

Architectural fabric AF9032 has been subjected to artificial thermal ageing to determine changes of the material parameters of the fabric. The proposed method is based on the accelerated ageing approach proposed by Arrhenius. 300 mm x 50 mm samples were cut in the warp and fill directions and placed in a thermal chamber at 80 &#176;C for up to 12 weeks or at 90 &#176;C for up to 6 weeks. Then after one week of conditioning at ambient temperature, the samples were uniaxially tensioned at a constant strain rate. Experimentally, the parameters were determined for the non-linear elastic (linear piecewise) and viscoplastic (Bodner&#8211;Partom) models. Changes in these parameters were studied with respect to the ageing temperature and ageing period. In both cases, the linear approximation function was successfully applied using the simplified methodology of Arrhenius. A correlation was obtained for the fill direction between experimental results and the results from the Arrhenius approach. For the warp direction, the extrapolation results exhibited some differences. Increasing and decreasing tendencies have been observed at both temperatures. The Arrhenius law was confirmed by the experimental results only for the fill direction. The proposed method makes it possible to predict real fabric behavior during long term exploitation, which is a critical issue in the design process.

Here, we simulate accelerated thermal ageing of technical fabric and see how this ageing process influences the mechanical properties of the fabric.

聚酯增强和聚氯乙烯涂层技术织物的人工热老化

Architectural fabric AF9032 has been subjected to artificial thermal ageing to determine changes of the material parameters of the fabric. The proposed ...

纤维复合材料层压板的制造和机械性能评估

Measuring the Mechanical Properties of Glass Fiber Reinforcement Polymer Composite Laminates Obtained by Different Fabrication Processes

The traditional wet hand lay-up process (WL) has been widely applied in the manufacturing of fiber composite laminates. However, due insufficiency in the forming pressure, the mass fraction of fiber is reduced and lots of air bubbles are trapped inside, resulting in low-quality laminates (low stiffness and strength). The wet hand lay-up/vacuum bag (WLVB) process for the fabrication of composite laminates is based on the traditional wet hand lay-up process, using a vacuum bag to remove air bubbles and provide pressure, and then carrying out the heating and curing process. 
Compared with the traditional hand lay-up process, laminates manufactured by the WLVB process show superior mechanical properties, including better strength and stiffness, higher fiber volume fraction, and lower void volume fraction, which are all benefits for composite laminates. This process is completely manual, and it is greatly influenced by the skills of the preparation personnel. Therefore, the products are prone to defects such as voids and uneven thickness, leading to unstable qualities and mechanical properties of the laminate. Hence, it is necessary to finely describe the WLVB process, finely control steps, and quantify material ratios, in order to ensure the mechanical properties of laminates. 
This paper describes the meticulous process of the WLVB process for preparing woven plain patterned glass fiber reinforcement composite laminates (GFRPs). The fiber volume content of laminates was calculated using the formula method, and the calculated results showed that the fiber volume content of WL laminates was 42.04%, while that of WLVB laminates was 57.82%, increasing by 15.78%. The mechanical properties of the laminates were characterized using tensile and impact tests. The experimental results revealed that with the WLVB process, the strength and modulus of the laminates were enhanced by 17.4% and 16.35%, respectively, and the specific absorbed energy was increased by 19.48%.

作者聚焦：使用湿法手糊/真空袋工艺提高纤维复合材料层压板质量 

This paper describes a fabrication process for fiber-reinforced polymer matrix composite laminates obtained using the wet hand lay-up/vacuum bag method.

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

The traditional wet hand lay-up process (WL) has been widely applied in the manufacturing of fiber composite laminates. However, due insufficiency in the ...

一个测试平台为聚合物的耐久性研究，并在同期Hygrothermo机械刺激纤维增强聚合物复合材料

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建筑与拆迁废塑料馏分对木聚合物复合性能的影响

拉伸压缩模式下的超声疲劳试验

解析高强共聚物芳纶纤维使其力学性能的测定

柔性单向复合层压板的切割程序、拉伸测试和老化

聚酯增强和聚氯乙烯涂层技术织物的人工热老化

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能