基于平模温度场的疲劳寿命分析

生物质在挤压成型时会产生大量的热能, 不仅影响着生物质的挤压成型效果,同时也制约着平模的疲劳寿命。平模作为平模成型机的关键零件,具有易磨损、疲劳寿命低的特点。平模在工作中受到交变载荷的作用,应力值即使没有超过材料的极限强度也有可能发生疲劳破坏,同时平模的工作温度也会对结构的疲劳寿命产生一定的影响。以ZL-300型平模成型机为研究对象,使用建模软件Solidworks建立平模的三维模型,利用有限元分析软件ABAQUS,对平模的热应力进行温度场和应力场的耦合仿真,再利用FE-SAFE软件对ABAQUS应力结果进行疲劳寿命分析,研究不同温度场(25,50,75,100,125,150,175, 200和225 ℃)对平模疲劳寿命的影响。结果表明,当平模工作表面温度为75 ℃时,平模的最大热应力为3.775×102MPa,最小循环次数为3.664×106,具有较好的疲劳寿命。
Large amount of heat is generated in the extrusion process of pellet manufacturing which affects not only the pellet quality but also the service life of the flat die. As a key part of a pellet mill, flat die has the characteristic of quick wear and fatigue due to the alternating load in service. In this condition, fatigue failure occurs even though the stress is below the failure strength. Temperature is another factor affects the fatigue life of flat die. In this study, a 3D model of the flat die of ZL-300 pellet mill was built by using Solidworks. The temperature and stress field in the flat die were simulated by ABAQUS which is a finite element analysis software. Then, FE-SAFE was used to calculate the fatigue life of the flat die based on the data of ABAQUS. Nine temperatures(25, 50, 75, 100, 125, 150, 175, 200 and 225 ℃)were chosen to make the analysis and the optimal performance was obtained when the temperature was 75 ℃. In this condition, the flat die showed the maximum thermal stress of 377.5 MPa and number of cycles at least 3.664×106