High-rate dynamic testing maschine

高速动态试验机

• 批准号: 523842938
• 金额: --
• 依托单位: Technische Universität Braunschweig
• 依托单位国家: 德国
• 项目类别: Major Research Instrumentation
• 财政年份: 2023
• 资助国家: 德国
• 起止时间: 2022-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/523842938?language=en
• 关键词: rate; dynamic; testing; maschine

The mechanical behavior of materials, structures or structural joint often differs under fast, high-rate dynamic loading compared to quasi-static loading. This is referred to as the so-called strain rate effect, which can lead to significant increases in strength at high test velocities, especially in the case of fiber-reinforced composite materials. Stiffness, elongation at break and failure modes can also differ at different strain rates. Knowledge of such strain rate effects of the materials is essential in the area of ​​structural crash and impact behavior.For such an experimental characterization, a servo-hydraulic dynamic high-rate testing machine is used, which is the subject of this proposal. A coupon or structural specimen is clamped in such a testing machine as in any conventional testing machine. However, the upper specimen clamping is strongly accelerated by means of hydraulic pressure before the load is abruptly introduced into the specimen. High-speed testing machines in the 160 kN performance class for high-strength fiber composite materials reach speeds of up to 20 m/s, which means that, depending on the specimen geometry, strain rates of up to approx. 600 1/s are typically realized (for comparison: quasi-static tests are carried out in the range of approx. 0.001 1/s ).For the data acquisition and measurement recording of force-displacement or stress-strain signals, a high-speed data recorder with a sufficiently high recording frequency is required and part of the system in order to record a sufficiently large number of data points during the test, which lasts only a few milliseconds. An optical high-speed measuring system based on the stereo correlation of two high-speed cameras (Digital Image Correlation) is typically used for the strain measurement.The procurement of this high-speed testing machine with an optical high-speed measuring system is part of the new appointment of Prof. Heimbs to the TU Braunschweig and is necessary for the scientific research activities of the Institute of Aircraft Design and Lightweight Structures (IFL) in the field of transient dynamics.Prof. Heimbs is a proven expert in this field and is developing it after his appointment at the IFL and expanding his extensive previous research activities. Numerous research projects are in planning and some have already been approved, which deal with the highz-rate dynamic characterization of lightweight and fiber composite materials as well as joining technologies, for example for innovative wing structures under bird strike loads, for new types of energy absorbers or for new methods of material modeling with strain rate-dependent intra- and interlaminar strengths and fracture energies for finite element simulations.

与准静态载荷相比，材料、结构或结构接头在快速、高速率动态载荷下的机械行为通常有所不同。这被称为所谓的应变率效应，它可以导致高测试速度下强度的显着增加，特别是在纤维增强复合材料的情况下。不同应变率下的刚度、断裂伸长率和失效模式也可能不同。了解材料的这种应变率效应对于结构碰撞和冲击行为领域至关重要。对于这种实验表征，使用了伺服液压动态高速试验机，这是本提案的主题。与任何传统测试机一样，将试样或结构样本夹紧在这种测试机中。然而，在将负载突然引入到试样中之前，上部试样夹紧通过液压被强烈加速。用于高强度纤维复合材料的 160 kN 性能等级的高速试验机可达到高达 20 m/s 的速度，这意味着，根据试样的几何形状，应变率高达约 20 m/s。通常可实现 600 1/s（作为比较：准静态测试在约 0.001 1/s 的范围内进行）。对于力-位移或应力-应变信号的数据采集和测量记录，需要具有足够高记录频率的高速数据记录仪并且是系统的一部分，以便在测试期间记录足够多的数据点，而测试仅持续几个小时 毫秒。基于两个高速相机立体相关（数字图像相关）的光学高速测量系统通常用于应变测量。采购这种带有光学高速测量系统的高速测试机是 Heimbs 教授到布伦瑞克工业大学新任命的一部分，对于飞机设计和轻质结构研究所 (IFL) 的科学研究活动是必要的。 瞬态动力学领域。教授。 Heimbs 是该领域公认的专家，在 IFL 任职后正在开发该领域，并扩大了他之前广泛的研究活动。许多研究项目正在规划中，有些已经获得批准，这些项目涉及轻质和纤维复合材料的高速率动态特性以及连接技术，例如鸟击载荷下的创新机翼结构、新型能量吸收器或用于有限元模拟的具有应变率相关的层内和层间强度以及断裂能的材料建模新方法。