Belt型两面顶模具温度场和应力场有限元分析及钢带缠绕数值模拟初探

Finite Element Analysis of Temperature and Stress Fields of Belt-type Apparatus and Preliminary Studies on Numerical Simulation of Steel-strip Winding Model

在人造金刚石合成工艺中,两面顶模具合成腔体内的压力和温度起着至关重要的作用。根据对叶蜡石力学和热学行为的研究,基于MSC.Marc非线性有限元软件,建立了压缸温度场和应立场的有限元模型,模型中考虑了热导率等物理参数随温度的变化规律。采用FORTRAN语言开发了适用于温度和压力边界条件加载的相应程序,获得了合成状态下压缸的温度场和应力场分布情况。由温度梯度引起的热应力数值较小,对压缸所产生的影响程度较小。压缸内壁径向应力达到5GPa,接近硬质合金极限抗压强度。轴向应力最大值1GPa,出现在压缸外壁中心处。同时还建立了钢带缠绕模具其动态缠绕过程的简化模型,采用一种修正的库仑摩擦边界条件,模拟了钢带的缠绕过程,获得了钢带缠绕层间的应力、应变分布情况。

In the manufacturing process of synthetic diamond, pressure and temperature in the working cavity of the belt-type apparatus are two critical factors that impact the product quality. Taking thermal conductivity and other temperature-dependent features into consideration, the finite element model of temperature and stress fields of the cylinder has been established with the employment of the nonlinear Finite Element Analysis software MSC · Marc, which is based on the researches of thermodynamic characteristics of pyrophyllite. Besides, the correlative programs suitable for loading boundary conditions are developed with FORTRAN. Then the ＇distributions of temperature and stress fields of the cylinder in the active state are obtained. Thermal stress caused by the temperature gradient has little influence on strength of the cylinder. The magnitude of radial stress along inter surface of the cylinder reaches 5 GPa that is the compressive ultimate strength of sintered-carbide materials. The magnitude of maximum axial stress of the cylinder is 1GPa, which appears in the central portion on the outer surface. In addition, the simplified model of strip-wound dies has been established to simulate the dynamic winding process, taking account of a certain modified Coulomb＇s friction model. Finally, the stress and strain distributions among steel-strip layers were obtained.