激光焊接Ⅰ芯全钢三明治板弯曲试验

The bending tests of laser-welded I-core all-steel sandwich panel

设计符合简支梁条件的实验装置,用于激光焊接Ⅰ芯全钢三明治板的弯曲性能测试.结果表明:所测得载荷与跨距中点挠度的载荷-挠度曲线上具有明显的弹性段、屈服点与最大载荷点;三明治板整体屈服时面板应力没有达到材料的屈服强度,芯板应力也没有达到材料的剪切强度,而是面板和芯板结合处的焊缝发生了屈服;三明治板变形形态的同步摄像表明,在最大载荷处,上面板出现局部屈曲迹象,屈曲以后变形主要集中在屈曲部分;利用三点弯曲外伸梁在弹性加载阶段的载荷和挠度,根据刚度分离法获得高度为44mm、芯板间距为78mm、面板和厚度为4mm的三明治板其弯曲刚度为0.662×106 N·m,剪切刚度为1.325×106 N·m.

Test rig consistent with the condition of the simple support was designed.It was to be used for testing the bending performance of laser-welded Ⅰ-core all-steel sandwich panel.The result showed that there were obvious elastic region,yield point and maximum load point on the load-deflection curve in the middle of the span.When sandwich panel yielded as a whole,the stress in face plate had not reached the yield strength of the material and the stress in core plate had not reached the shear strength of the material,but the weld of junction before face plates and core happened to yield.Sandwich panel deformation pattern of synchronous shooting showed that on the top face plate of sandwich panel appeared signs of local bucking under maximum load,deformation of sandwich panel concentrated on bucking areas after bucking; The load and deflection of elastic region of three-point bending overhanging beams was used to calculate bending stiffness and shearing stiffness with the method of stiffness dissociation.The stiffness was 0.662×106 N · m,and 1.325×106 N · m,respectively when the height of the sandwich panel was taken as 44 mm,the spacing of core plates as 78 mm,and the thickness of the face plate as 4 mm.