Method for predicting interlayer thermal stress distribution in selective laser melting process based on COMSOL

Abstract

The invention provides a method for predicting interlayer thermal stress distribution in the selective laser melting process based on COMSOL. The method comprises the following steps: S1, constructing a three-dimensional solid heat transfer and structural mechanics transient model based on COMSOL; s2, determining parameters in a simulation process; s3, determining the material attribute of the powder to be melted; s4, determining moving Gaussian heat source parameters; s5, constructing a geometric model of the powder bed; s6, achieving layer-by-layer manufacturing of selective laser melting; s7, carrying out grid division and calculating node temperature; and S8, predicting interlayer thermal stress distribution and residual thermal stress distribution according to a result of the step S7. According to the method, the laser heat source effect in the machining process is simulated through a moving Gaussian heat source mold, and a powder bed is replaced with a uniform material powder bed; in addition, the structural mechanics module is used for simulating the thermal stress generated by the layer and the deformation condition of a workpiece when the structural mechanics module moves along with a heat source, the layer-by-layer manufacturing process of the selective laser melting technology is simulated, and prediction of thermal stress among multiple layers and residual thermal stress is achieved.

Description

technical field [0001] The invention relates to the technical field of thermal stress distribution, in particular to a COMSOL-based method for predicting interlayer thermal stress distribution in selective laser melting technology. Background technique [0002] Selective laser melting technology is a near-net-shape technology based on material discrete-gradual accumulation method to manufacture solid parts. This technology usually uses metal powder as the raw material, sets the laser scanning path through the pre-layering process of the three-dimensional model, and uses the high-energy laser beam to melt the metal powder layer by layer according to the set scanning path, so that it can be rapidly solidified and accumulated to form a high-performance component. . In the process of laser melting technology, metal materials undergo rapid heating, solidification and cooling processes, during which large thermal stress and structural stress caused by solid-state phase transition...

AI Technical Summary

Problems solved by technology

However, loading this volumetric heat source on each slice layer can only predict the distribution of thermal stress between layers, and cannot accurately predict the distribution of thermal stress accumulated in a single scan on each layer.

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