矩形截面型材平面拉弯弹复解析和试验验证

Springback Analysis of Plane Stretch-bending for Profile with Rectangular Cross-section and Experimental Verification

在满足工程应用要求的平面拉弯基本假设下,构建矩形截面型材平面拉弯的力学模型。详细描述拉弯变形后型材横截面上应力应变分布的不同状态,基于双线性材料模型假设给出不同状态下应力应变的数学表达式,通过对截面应力的积分推导出应变中性层、截面弯矩与拉力和弯曲半径的关系,并给出不同应力应变分布状态的判定条件。确立矩形截面型材平面拉弯弹复问题的理论解析方法并给出拉弯弹复的规律,表述弹复后的残余半径与拉力和弯曲半径的关系。设计一种新型的拉弯试验模具并开展矩形截面型材拉弯弹复的试验研究,利用有限元分析软件ABAQUS开展基于物理试验的有限元模拟分析,物理试验和有限元分析所获得的拉弯弹复规律与理论解析结果一致,数据吻合。该研究方法为其他截面型材拉弯弹复的研究提供理论参考,研究结果具有一定工程应用价值。

The mechanical models of profile with rectangular cross-section plane stretch-bending are established based on the basic plane stretch-bending hypotheses which meet the demand of engineering application. Different distribution states of stress and strain on the cross-section after stretch-bending deformation are described in detail. The mathematical expressions of tress and strain are given based on the hypothesis of bilinear hardening material model. The relationships among strain neutral layer, moment, tension and bending radius are derived through integrating of stress. The method of discriminating different distribution states of stress and strain is given. The analytic method for springback of profile with rectangular cross-section plane stretch-bending is obtained. The springback laws are explored by this analytic method. A new set of mold for stretch-bending experiments is designed and the experimental research on stretch-bending of profile with rectangular cross-section is carried out. Based on the physical experiment, the finite element simulation analysis is carried out using finite element analysis software ABAQUS. The springback laws obtained by experiment and finite element analysis are agreed well with the analytical results. This study method provides a theoretical reference for stretch-bending of profile with other cross-section, meanwhile, the study results have certain engineering guidance value.