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Innovative photomechanical approaches in identification of the dynamic mechanical behaviour of materials

识别材料动态机械行为的创新光机械方法

基本信息

批准号：
EP/L026910/1
负责人：
Fabrice Pierron
金额：
$ 154.52万
依托单位：
University of Southampton
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2014
资助国家：
英国
起止时间：
2014 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FL026910%2F1
关键词：
Innovative photomechanical approaches identification dynamic

项目摘要

In many areas of engineering, materials suffer deformation at high rates. This is the case when structures undergo impact, crash, blast, etc. but also in material forming like stamping or machining for instance. Therefore, it is essential for design engineers to have reliable mechanical models to predict the behaviour of the materials in such applications. This is enhanced by the spectacular progress in numerical simulation which now enables to perform detailed computations of very complex situations. However, robust experimental identification of refined high strain rate deformation models is lagging behind and hinders the delivery of the full potential of numerical simulations for the benefit of society: safer infrastructures (buildings, bridges, dams), safer means of transportation (crashworthiness of vehicles) etc. Indeed, in order to perform experimental identification of high strain rate material models, engineers only have a very limited toolbox based on test procedures developed decades ago. The best example is the so-called Split Hopkinson Pressure Bar (SHPB) which has proved extremely useful but has important intrinsic limitations due to the stringent assumptions required to process the test data. These assumptions are the consequence of the very limited instrumentation for which such tests were developed, usually a few strain gauge readings for the standard SHPB set-up. The recent advent of full-field deformation measurements using imaging techniques has allowed novel approaches to be developed and exciting new testing procedures to be imagined for the first time. The objective of the present project is to lay the foundations of a new era in dynamic testing of materials based on the availability of digital imaging technology to provide full-field deformation measurements at very high speeds. One can then use this information in conjunction with efficient numerical inverse identification tools such as the Virtual Fields Method to design novel test procedures to identify material parameters at high rates. The underpinning novelty is to exploit the inertial effects developed in high strain rate load. These have hitherto been regarded as undesirable in conventional testing. However, in the identification process they can play the role of a volume distributed load cell for which readings are embedded in the full-field deformation measurements. The idea is ground breaking as it has the potential to lift the current major limitations of high strain rate test, i.e. small specimen and constant velocity. The present proposal aims at providing a platform for the applicant to develop this methodology for many different types of situations in terms of materials, loading configuration and strain rate range. The project has the potential to revolutionize high strain rate testing of materials and hence enhance our knowledge of material behaviour. This will in turn benefit many sectors of engineering and society in the long term.

在许多工程领域，材料会发生高速变形。当结构遭受冲击、碰撞、爆炸等时就会出现这种情况，而且在冲压或机加工等材料成型中也会出现这种情况。因此，设计工程师必须拥有可靠的机械模型来预测此类应用中材料的行为。数值模拟的巨大进步增强了这一点，现在可以对非常复杂的情况进行详细计算。然而，精细化高应变率变形模型的稳健实验识别仍然滞后，并阻碍了数值模拟造福社会的全部潜力的发挥：更安全的基础设施（建筑物、桥梁、水坝）、更安全的运输工具（车辆的耐撞性）等。事实上，为了对高应变率材料模型进行实验识别，工程师只有非常有限的基于几十年前开发的测试程序的工具箱。最好的例子是所谓的分离霍普金森压力棒（SHPB），它已被证明非常有用，但由于处理测试数据所需的严格假设而具有重要的内在局限性。这些假设是开发此类测试的仪器非常有限的结果，通常是标准 SHPB 设置的一些应变仪读数。最近使用成像技术进行全场变形测量的出现使得新的方法得以开发，并且首次想象出令人兴奋的新测试程序。本项目的目标是基于数字成像技术的可用性，以非常高的速度提供全场变形测量，为材料动态测试的新时代奠定基础。然后，人们可以将这些信息与有效的数值逆识别工具（例如虚拟场方法）结合使用，设计新颖的测试程序，以高速识别材料参数。其基础新颖之处在于利用高应变率负载中产生的惯性效应。迄今为止，这些在常规测试中被认为是不受欢迎的。然而，在识别过程中，它们可以发挥体积分布式称重传感器的作用，其读数嵌入全场变形测量中。这个想法是开创性的，因为它有可能克服当前高应变率测试的主要限制，即小样本和恒定速度。本提案旨在为申请人提供一个平台，以针对材料、负载配置和应变率范围方面的许多不同类型的情况开发该方法。该项目有可能彻底改变材料的高应变率测试，从而增强我们对材料行为的了解。从长远来看，这将使工程和社会的许多部门受益。