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提出了一种基于瞬时相对线速度的搅拌头产热模型,利用ABAQUS有限元软件建立了焊接过程温度场有限元模型,对摩擦搅拌焊接过程温度场进行了数值模拟并利用有限元模型分析了焊接温度场的不对称性;在温度场有限元模型的基础上建立了摩擦搅拌焊接过程热力耦合有限元模型,利用ABAQUS有限元软件对焊接过程动态应力和焊后残余应力的分布进行了仿真模拟。结果表明:焊接过程最高温度低于被焊材料熔点,搅拌头前方温度梯度大于搅拌头后方,并且温度梯度随焊接速度的提高变化更为剧烈;焊接过程试件内存在动态应力场,随着试件的冷却逐渐转化为残余应力场,横向残余应力在试件内分布较广,大部分区域内为横向拉应力,而在试件周围拉应力逐渐转变为压应力,纵向残余应拉应力只局限于接近焊缝的一个很窄的区域,在周围区域有较低的压应力,距离焊缝越远其值越低。
A heat production model based on instantaneous relative linear velocity was proposed. The finite element model of temperature field in welding process was established by using ABAQUS finite element software. The temperature field in friction stir welding was numerically simulated and analyzed by finite element analysis Temperature field. Based on the finite element model of the temperature field, a coupled thermo-mechanical finite element model of the friction stir welding process was set up and the distribution of the dynamic stress and the residual stress after welding were simulated by ABAQUS finite element software. The results show that the maximum temperature of the welding process is lower than the melting point of the material to be welded, the temperature gradient in front of the mixing head is greater than the rear of the mixing head, and the temperature gradient changes more acutely with the welding speed increasing. The cooling gradually transformed into the residual stress field. The transverse residual stress was widely distributed in the specimen and transverse tensile stress was observed in most of the regions. However, the tensile stress around the specimen gradually transformed into compressive stress, and the longitudinal residual stress should be limited In a narrow area close to the weld, there is lower compressive stress in the surrounding area, and the farther the weld is, the lower the value is.