SBIR Phase I: Residual Stress and Part Distortion Prediction in Machined Workpiece Surfaces

这个小型企业创新研究第一阶段项目将开发和验证三维有限元建模能力，以预测加工引起的残余应力。该项目将极大地扩展目前仅限于2D残余应力分析和最近的3D斜切削单刃几何模型的最新技术。残余应力因其对表面质量、疲劳和工件变形的影响而变得越来越重要。残余应力对工业有很高的经济影响，因为制造成本是在任何测量或检测之前发生的。测试方法非常昂贵、困难，而且不是为生产目的而开发的。工业和政府测试已经确定，机械加工引起的残余应力的大小可能足以导致零件变形和成品零件超出公差的情况。该项目将演示一种预测完整制造部件上的残余应力影响的综合方法。在任何制造之前，将对加工参数引起的工件残余应力进行建模、验证，然后集成到完整的零件分析中，以确定完整零件的最终应力和变形状态。商业应用包括大型薄壁航空航天零件(如翼梁)、结构部件和易受高疲劳率影响的零件(转子机翼轮毂和承载部件、主轴、结构和动力总成部件)。预测和控制由加工过程引起的零件变形具有很高的经济影响。一个零件因超出公差条件而报废的成本很容易超过100,000美元，通常会造成数周的生产延迟和报废。汽车行业，主要是发动机机体制造、活塞衬里、轴承、主轴和难车削应用(通常)也可以从这项技术中受益。

This Small Business Innovative Research Phase I project will develop and validate a three-dimensional finite element modeling capability to predict machining induced residual stresses. This project will significantly extend the current state-of-the-art that is limited to 2D residual stress analysis and recently, 3D oblique cutting models of single cutting edge geometries. Residual stress has become increasingly important because of its effects upon surface quality, fatigue, and workpiece distortion. Residual stress has high economic impact to industry since the cost of manufacture is incurred prior to any measurement or detection. Testing methods are very expensive, difficult, and not developed for production purposes. Industry and government testing has determined that machining induced residual stresses can be significant enough in magnitude to induce part distortion and out-of tolerance conditions on completed workpieces. This project will demonstrate an integrated approach to predicting residual stress effects upon completely manufactured parts. Workpiece residual stress due to machining parameters will be modeled, verified, and then integrated into a complete part analysis to determine the final state of stress and distortion for a complete workpiece part prior to any manufacture.The commercial applications include large, thin walled aerospace parts (such as wing spars), structural components, and parts susceptible to high rates of fatigue (rotor wing hubs and load carrying parts, spindles, structural, and powertrain components). The economic impact to predict and control part distortion induced by machining processes is very high. The cost of rejection of one part due to out-of-tolerance conditions can easily exceed $100,000 and routinely create weeks in production delay and scrap. The automotive sector, primarily within engine block manufacture, piston liners, bearings, spindles, and hard turning applications (generally) could also benefit from this technology.