MRI: Acquisition of a Drop Tower Impact Test Capability at Penn State Erie, The Behrend College

这项主要研究仪器（MRI）奖支持宾夕法尼亚州立大学伊利，贝伦德学院的落塔冲击测试仪器的收购。 许多组件和结构故障是由于突然发生的灾难性断裂，通常没有警告。 解决这些影响的学科是断裂力学。 如果机械载荷达到临界水平，则可能发生灾难性故障。 了解可能导致断裂的条件需要能够改变温度、部件形状和冲击速度等参数的测试设施。 突然断裂事件发生在非常短的时间内，如毫秒或微秒。 这需要高速摄像机的能力，可以捕捉这些事件进行详细研究。 落塔冲击测试仪器具有这些功能，并补充了一套其他测试技术在宾夕法尼亚州立大学伊利。 包括金属、聚合物和复合材料在内的各种材料的断裂行为都可以理解，这将使必须设计抗故障部件和结构的行业合作伙伴能够更密切地合作。 该仪器还将在大学水平的工程课程中进行断裂和冲击方面的教学，同时还支持以学生为中心的本科生研究，塑料工程的工业劳动力发展，和一个与中学女生的暑期外展计划。研究计划的主要目标是围绕这一收购是探索率依赖的韧性/脆性断裂转变为长期材料配方和新的化学和微观结构分布。范围还包括使用这种技术来诱导定向聚合物样品的受控快速变形，以更好地了解热塑性塑料中的应变诱导结晶，建立在宾夕法尼亚州立大学伊利的研究基础上。几个断裂模拟分析理论已计划，包括基本工作的断裂，裂纹张开位移，裂纹尖端张开位移，虚拟裂纹闭合，和J积分。 所有这些都有局限性，通常是由基本的材料特性造成的。 与数值分析技术相结合，落塔冲击试验仪器提供的数据将允许这些建模方法进行评估，发展和优化，用于广泛的聚合物，金属和复合材料。 其基本目标是基于材料变形和裂纹扩展的准确表征，为各种形态和结构的材料建立可靠的断裂模型。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Major Research Instrumentation (MRI) award supports the acquisition of a drop tower impact test instrument at Penn State Erie, The Behrend College. Many component and structural failures are due to sudden catastrophic fractures that often occur without warning. The discipline that addresses these effects is fracture mechanics. If mechanical loading reach critical levels, catastrophic failure may occur. Understanding the conditions that may lead to fracture requires test facilities that can vary parameters such as temperature, component shape, and impact velocity. Sudden fracture events occur over very small timeframes, like milliseconds or microseconds. This requires high speed camera capability that can capture these events for detailed study. The drop tower impact test instrument has these features and complements a set of other test techniques at Penn State Erie. A wide range of materials, including metals, polymers and composites, can be understood in terms of their fracture behavior and this will enable closer collaboration with industry partners who must design failure resistant parts and structures. This instrument will also enable instruction on fracture and impact in engineering courses at the college level, while also supporting student centered undergraduate research, industrial workforce development in plastics engineering, and a summer outreach program with middle school girls.The primary objective of the research program to be centered on this acquisition is to explore the rate-dependence of the ductile/brittle fracture transition for both longstanding material formulations and new chemistries and microstructure distributions. The scope also includes use of this technique to induce controlled rapid deformation of oriented polymer samples to better understand strain-induced crystallization in thermoplastics, building on established research at Penn State Erie. Several fracture modeling analysis theories have been planned including essential work of fracture, crack opening displacement, crack tip opening displacement, virtual crack closure, and J-integral. All of these have limitations, often imposed by the fundamental material characteristics. In combination with numerical analysis techniques, the data provided by the drop tower impact test instrument capability will allow these modeling approaches to be evaluated, evolved and optimized for a broad range of polymeric, metallic and composite materials. The fundamental goal is to achieve reliable fracture models for materials of variable morphologies and architectures based on accurate characterization of material deformation and crack propagation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.