激光焊接三明治板T形接头弯曲变形及失效研究

Bending deformation and failure of laser welded T-joint of sandwich plates

针对低合金钢CCS-B为母材的I型三明治板T形接头,通过一种侧向弯曲加载试验装置进行了加载试验。采用微距摄像技术对T形接头的变形及失效过程进行跟踪拍摄,利用材料试验机记录整个加载动力学响应过程,并对T形接头弯曲过程进行模拟分析。卸载后,对接头断口进行SEM观察。结果表明,T形接头屈服强度及极限强度分别为337 MPa,501 MPa;接头裂纹起裂位置是位于芯板中性轴上端焊缝连接处间隙的外侧,并且随着加载进行,向焊缝中心扩展;当连接处屈服区域宽度超过连接处芯板宽度的1/3时,接头达到屈服强度;当其超过1/2时,接头达到承载极限并快速失效。

The lateral bending loading test of the T-joint made of I-core sandwich plates with base metal of low-alloy CCS-B steel was performed by using the lateral bending loading test device.Tracking shooting T-joint lateral bending deformation and failure process was investigated by the macro camera technology,the entire loading dynamic response process was recorded by the material testing machine,and the bending process of T-joint was simulated.The joint fracture was investigated by SEM.The results show that the yield strength and ultimate strength of the T-joint are 337 MPa and 501 MPa,respectively.The initiation crack is located outside of the gap at the weld connection in the upper of the neutral axis of the core plate and the crack extends to the center of the weld in the wake of loading.When the width of yield zone at the junction exceeds 1/3 of the width of the core panel,the joint reaches the yield strength;when the width of yield zone exceeds 1/2,the joint reaches the maximum bearing capacity and fast failures.