Influences of environmental conditioning and damage on the dispersive propagation and damping behaviour of Lamb waves in fiber reinforced plastics

环境条件和损伤对纤维增强塑料中兰姆波色散传播和阻尼行为的影响

基本信息

批准号：
212716418
负责人：
Professor Dr.-Ing. Axel Herrmann
金额：
--
依托单位：
Faserinstitut Bremen e.V. (FIBRE)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2011
资助国家：
德国
起止时间：
2010-12-31 至 2015-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/212716418?language=en
关键词：
Influences environmental conditioning damage dispersive

项目摘要

Within the first 18 months of the initial funding phase, which have been completed at the time of preparation of this follow-up proposal, the influence of environmental and loading conditions (humidity absorption, temperature changes, static and dynamic loading), and combinations thereof, on wave propagation in fiber reinforced plastics was investigated. Additionally, methods where created to both predict changes to the propagation characteristics if the waveguides state is known and to compensate for these changes to enable the use of Lamb waves for structural health monitoring (SHM).The proposed second funding phase initially contains the work packages which were planned for the time between month 25 and 36 in the original proposal, adapted to the findings of the first phase. Primarily, this includes the conclusion of the experimental work packages and their evaluation. Additionally, the findings of the first phase are to be used to develop/extent methods that allow the evaluation of the structures health if the sensor response changes due to factors unrelated to the formation of damage. From these methods and the experimental findings, guidelines are to be developed which contain rules for the design of sensor networks for SHM under realistic conditions.It is furthermore proposed that the second funding phase contains new work packages which deal with the high sensitivity of the sensor responses to factors that show manufacturing related scatter, which were identified in the first phase. These factors include variation of the local fiber volume content (e.g. due to textile gaps), the fiber orientation and the adhesive layers properties. As it is expected that the impact of these factors is itself a function of the environmental conditions investigated in the first phase, it is also proposed to investigate the combined influence of manufacturing-related property scatter and both humidity absorption (as an example for a slowly changing influence varying over the thickness of the laminate) and temperature (as an example for a factor that can change very fast). Experiments using both simple plates and plates containing structural discontinuities are planned, with the influence of locally varying, non-damage-related changes (esp. humidity absorption) on interactions between wave and structural discontinuity (reflection, mode conversion etc.) being of special interest.Finally, the work package dealing with the creation of guidelines for the design of sensor networks will be extended to include the aforementioned influencing factors, namely manufacturing-related property scatter in combination with structural discontinuities and non-damaging environmental conditions. To achieve this, it is proposed to use both FE-based approaches to predict areas where the sensor responses complexity would be critically high and to develop/investigate methods to localize the SHM systems task, i.e. by limiting its task or the area covered by the waves.

在准备后续提案时完成的初始资金阶段的前18个月内，环境和加载条件的影响（湿度吸收，温度变化，静态和动态加载）以及组合的组合，研究了纤维增强塑料的波传播。此外，如果已知波导状态并弥补这些更改以使羔羊波在结构性健康监测（SHM）中使用这些变化，则可以预测传播特征的变化的方法。计划在原始提案中的第25至36个月之间的时间计划，适合第一阶段的发现。首先，这包括实验工作包的结论及其评估。此外，如果由于与损害形成无关的因素而变化，则第一阶段的发现应用于开发/范围方法，以评估结构健康。从这些方法和实验结果中，将制定指南，其中包含在现实条件下为SHM设计的传感器网络的规则。对显示制造相关散射的因素的响应，这些因素在第一阶段被鉴定出来。这些因素包括局部光纤量含量（例如，由于纺织间隙）的变化，纤维方向和粘合剂层的性质。正如预期的那样，这些因素的影响本身是第一阶段研究的环境条件的函数，还建议研究与制造相关性质散射和湿度吸收的综合影响（作为缓慢的例子变化的影响在层压板的厚度上变化）和温度（作为可以很快变化的因素的一个例子）。计划使用两个简单的板和包含结构性不连续性的实验，并在局部变化，无损害相关的变化（尤其是湿度吸收）对波浪和结构不连续性（反射，模式转换等）之间的相互作用的影响是特殊的兴趣。从最终的角度来看，涉及建立传感器网络设计准则的工作包将扩展到包括上述影响因素，即与制造相关的特性分散，结构不连续性和非损害环境条件。为了实现这一目标，建议使用两种基于FE的方法来预测传感器响应的复杂性将非常高的领域，并开发/调查方法以本地化SHM系统任务，即通过限制其任务或限制其涵盖的领域波浪。