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Uncertainty quantification of residual stresses induced by laser peening simulation.

机译:激光喷丸模拟引起的残余应力的不确定度量化。

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摘要

Advanced mechanical surface enhancement techniques have been used successfully to increase the fatigue life of metallic components. These techniques impart deep compressive residual stresses into the component to counter potentially damage-inducing tensile stresses generated under service loading. Laser Peening (LP) is an advanced mechanical surface enhancement technique used predominantly in the aircraft industry. To reduce costs and make the technique available on a large-scale basis for industrial applications, simulation of the LP process is required. Accurate simulation of the LP process is a challenging task, because the process has many parameters such as laser spot size, pressure profile, and material model that must be precisely determined. In the LP process material is subjected up to strain rates of 106s -1, which is very high compared to conventional strain rates. The importance of an accurate material model increases because the material behaves significantly different at such high strain rates. One of the objectives of this research is to make advancements in the simulation of residual stresses induced by laser peening. Validation of various material models under investigation that could be used in simulation and design is performed. Inverse optimization-based methodology is developed for simulation of residual stresses for materials such as InconelRTM718. The procedure involves optimizing the model constants for one load case and using the same constants for other load cases. The second aspect of this research is to develop a framework for uncertainty quantification of the residual stress field induced by the LP process by propagation of regression uncertainty. Development methodology includes identification of regression uncertainty as a source of input uncertainty and using the bootstrap method to verify the multivariate normality assumption of the model constant estimates. The propagation of the input uncertainty is performed using Taylor series expansion and sensitivity analysis. A confidence band for the entire residual stress field is obtained and validated using the Monte Carlo analysis.
机译:先进的机械表面增强技术已成功用于增加金属部件的疲劳寿命。这些技术将深压缩残余应力施加到组件中,以抵消在使用载荷下可能产生的可能引起破坏的拉伸应力。激光喷丸(LP)是一种先进的机械表面增强技术,主要用于飞机行业。为了降低成本并使该技术可大规模用于工业应用,需要模拟LP工艺。 LP工艺的准确仿真是一项艰巨的任务,因为该工艺具有许多参数,例如激光点尺寸,压力分布和必须精确确定的材料模型。在LP工艺中,材料承受的应变率为106s -1,这与常规应变率相比非常高。精确的材料模型的重要性增加了,因为材料在如此高的应变速率下表现出明显不同。这项研究的目的之一是在模拟激光喷丸引起的残余应力方面取得进展。进行了可用于仿真和设计的各种材料模型的验证。开发了基于逆优化的方法,用于模拟InconelRTM718等材料的残余应力。该过程涉及针对一个载荷工况优化模型常数,并针对其他载荷工况使用相同的常数。本研究的第二个方面是为通过回归不确定性的传播而对LP过程引起的残余应力场进行不确定性量化开发一个框架。开发方法包括将回归不确定性确定为输入不确定性的来源,并使用自举方法来验证模型常数估计的多元正态性假设。输入不确定度的传播使用泰勒级数展开和灵敏度分析来执行。使用蒙特卡洛分析获得并验证了整个残余应力场的置信带。

著录项

  • 作者

    Amarchinta, Hemanth.;

  • 作者单位

    Wright State University.;

  • 授予单位 Wright State University.;
  • 学科 Engineering, Mechanical.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 201 p.
  • 总页数 201
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 ;
  • 原文服务方 国家工程技术数字图书馆
  • 关键词

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