两点弯曲下柔性玻璃变形和疲劳行为研究

基于两点弯曲法加载方式及原理,分析了柔性玻璃的弯曲变形及疲劳行为,推导了弯曲曲率半径、弯曲应力与板间距之间的定量关系,基于高周疲劳理论,建立了柔性玻璃的应力-寿命(S-N_f)模型。结果表明,两点弯曲作用下,柔性玻璃试样的厚度不会改变其弯曲挠曲线轨迹,通过调节板间距,可获得试验所需的试样弯曲曲率半径。忽略柔性玻璃厚度的影响,试样的弯曲曲率半径与板间距呈线性关系,弯曲最大拉应力与弯曲曲率半径成反比。选择的最小弯曲曲率半径R_(min)越大,试样疲劳寿命越高,最大弯曲曲率半径R_(max)值的增大并不会显著影响试样的弯曲疲劳次数。Basquin模型能够有效预测不同交变应力或不同弯曲曲率半径作用下柔性玻璃的弯曲疲劳寿命。

铝板矫直中的弹塑性弯曲变化规律实验研究

针对铝板在大压下量矫直过程中出现弯曲曲率大于矫直辊曲率的现象,本文在11辊辊式矫直设备上以1060铝板为研究对象进行了矫直实验,研究了铝板的最大弯曲位置、最小弯曲曲率半径以及铝板与矫直辊的接触位置之间的关系。结果表明:随着压下量的增大,铝板最大弯曲位置偏向于板材的出口方向,偏向的趋势减小;铝板最大弯曲量将大于压下量,两者差值也随之增大;铝板材与矫直辊的接触点不在铝板的最大弯曲位置,接触角随着压下量的增大逐渐增大;随着压下量的增大,以矫直辊顶点对应板材的弯曲曲率作为最大曲率并不可取,且由于塑性铰现象,铝板的最大曲率半径会小于矫直辊半径。

Flexible bending of aluminum profiles with polyurethane pad

The high flexibility of profile bending with hyperelastic pad enables it to be a promising method for small lot or single part production, especially for space frame and roof-rail parts in automotive and aerospace industries. Bending of two aluminum profiles with different sections was carried out to investigate the effect of main process parameters on the bending process. Results show that the shape of the cross-section and its relative thickness and section modulus in bending are the main factors that determine the bending properties of the profiles. Roller stroke, properties of polyurethane pad and constraints on profiles are key factors that determine the bending radius and section deformation of bent profiles. Failures and quality problems met in experiments were also analyzed.