Acousto-Plastic Deformation of Metal by Nonlinear Stress Waves

非线性应力波引起的金属声塑性变形

• 批准号: 0600060
• 负责人: John Yu
• 金额: --
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0600060&HistoricalAwards=false
• 关键词: Acousto; Plastic; Deformation; Metal; Nonlinear

The present research project addresses the need to understand the Acousto-Plastic Effect (APE), which occurs when metal specimens are deformed (in compression or tension) and ultrasonic vibrations are superimposed. When the APE occurs, a remarkable transitory softening is observed. The research will address APE beyond the phenomenological descriptions presented in the current literature. Theoretical and numerical studies will be conducted to clarify the unusual metal morphology induced by ultrasonic vibrations. The research directly addresses the dynamic nature of the processes rather than treating the transitory metal softening effect by introducing an ad-hoc constitutive relation between strain and the apparent static stress. A comprehensive theoretical model is being developed for the evolving nonlinear stress waves. The model equations will be solved by using the space-time Conservation Element and Solution Element (CESE) method, a novel numerical framework for high-fidelity solution of nonlinear hyperbolic systems. Successful development of the theoretical and modeling capabilities will demonstrate a new paradigm for high-fidelity simulation of nonlinear stress waves in solids. The use of parallel computing for very large-scaled calculations could point to a new direction for high performance computation for material simulations. With in-depth understanding of the APE and the accurate modeling tool, implementation of high-power ultrasounds to various metal forming/joining processes could be achieved. The envisioned modeling tool could also be applied to various nonlinear wave problems, including seismic wave propagation in earth and ultrasonic propagation in biological tissues. The research project will foster a meaningful collaboration between researchers at the Ohio State University, and ultrasound specialists and materials scientists at the Ford Motor Company. Undergraduate and graduate students as well as practicing professions in the automotive industry will be integrated into the research project via educational outreach and direct training.

目前的研究项目解决了理解声塑性效应（APE）的需要，这种效应发生在金属试样变形（压缩或拉伸）和超声波振动叠加时。当APE发生时，观察到显着的短暂软化。该研究将解决APE超越现象学的描述在目前的文献中提出。将进行理论和数值研究，以阐明超声振动引起的异常金属形态。该研究直接解决了过程的动态性质，而不是通过引入应变和表观静态应力之间的特设本构关系来处理短暂的金属软化效应。对于演化的非线性应力波，正在建立一个全面的理论模型。模型方程将采用时空守恒元和解元（CESE）方法求解，CESE是一种新颖的高保真解非线性双曲型系统的数值框架。理论和建模能力的成功发展将为固体中非线性应力波的高保真模拟提供新的范例。在大规模计算中使用并行计算可以为材料模拟的高性能计算指明一个新的方向。通过对APE的深入了解和精确的建模工具，可以实现对各种金属成形/连接过程的高功率超声波。所设想的建模工具还可以应用于各种非线性波问题，包括地震波在地球中的传播和超声波在生物组织中的传播。该研究项目将促进俄亥俄州立大学的研究人员与福特汽车公司的超声波专家和材料科学家之间有意义的合作。通过教育拓展和直接培训，本科生和研究生以及汽车行业的从业人员将被纳入研究项目。