搅拌摩擦焊三维粘塑性热力耦合有限元数值模拟

针对搅拌摩擦焊(friction stir welding,FSW)的特点,建立了基于固体力学的刚粘塑性热力耦合有限元方程,并采用网格局部加密自适应跟随技术对FSW过程进行数值模拟,获得了焊接过程的温度、应力、应变分布特征及金属流动规律,预测焊接过程中所产生的缺陷.结果表明,FSW过程中试件的温度分布不对称,应变沿板厚的方向分布不一致,焊缝区产生了剧烈的塑性变形,因此FSW是一个典型的三维剧烈的塑性变形过程,热塑性变形机制是焊接接头形成的主要机制.

3D coupled thermo-mechanical visco-plastic finite element simulation of friction stir welding process

Based on the character of the friction stir welding,the coupled thermo-mechanical visco-plastic finite element formulation was established,and the local adaptive mesh method was used for simulating the friction stir welding(FSW)processing.Based on the numerical result,the distribution of temperature,strain,stress and metal flow state of the specimen were obtained,and the defects were forecasted during the welding process.The results show that the temperature distribution of the workpiece is asymmetry; strain distribution is not uniformity along the thickness direction of the plate,and severe plastic deformation exists in the welding zone.So the FSW is 3D severe plastic deformation process,and the thermoplastic is the real principle of weld formation.