异质材料选区激光熔化的成形过程仿真研究及设备结构设计

发布时间：2018-05-31 12:52

本文选题：选区激光熔化 + 异质材料　；参考：《北京理工大学》2015年硕士论文

【摘要】：功能梯度材料的研究已经迅速成为国内外研究的活跃项目,功能梯度材料是一种新型的功能复合材料,它的两侧由不同性质的材料组成,中间部分的组成和结构连续地呈梯度变化,从而使材料的性质和功能也呈梯度变化,克服了不同材料的不匹配因素。选区激光熔化成形技术(Selective Laser Melting,简称SLM)是近十几年才发展起来的新型快速成形(Rapid Prototyping)技术,独特的优越性使其成为最有发展潜力的快速成形技术之一。在成形过程中遇到两种材料需要同时成形的时候,由于不同的材料有不同的属性,所以两种材料结合处的成形对试验参数及工艺参数提出了特殊的要求。本文首先提出了一种用SLM设备制备异质材料零件的方法,并对其主要执行机构进行了设计。接下来采用计算机数值模拟的方法,对SLM成形过程中两种材料的结合处进行了深入研究。采用材料单元属性变换和单元生死技术相结合的方法,在考虑相变、材料热物性随温度变化条件下对选区激光熔化成形过程的三维瞬态温度场进行了数值模拟,利用参数化语言(APDL)实现了激光高斯热源的移动加载,分别建立了单层单道和多层多道的有限元模型并对其成形区域进行预测。基于温度场的计算结果,采用热力耦合方法,建立了选区激光熔化过程应力应变场分析模型,分析了热力演变规律和残余应力分布,为以后的实际加工提供依据。
[Abstract]:The study of functionally graded materials has rapidly become an active project at home and abroad. FGM is a new type of functional composite material, and its two sides are composed of materials of different properties. The composition and structure of the middle part continuously change with gradient, so that the properties and functions of the material also change gradient, which overcomes the mismatch factors of different materials. Selective Laser melting (SLM) is a new rapid prototyping technology developed in recent years. Its unique advantages make it one of the most promising rapid prototyping technologies. When two kinds of materials need to be formed at the same time in the process of forming, because different materials have different properties, the forming of the two kinds of materials has put forward special requirements to the test parameters and process parameters. In this paper, a method of fabricating heterogeneous material parts with SLM equipment is proposed, and its main executive mechanism is designed. Then the combination of two kinds of materials in SLM forming process is studied by computer numerical simulation. Using the method of material element attribute transformation and element birth and death technique, the three-dimensional transient temperature field of selective laser melting forming process is numerically simulated under the condition of considering phase change and the change of material thermal property with temperature. The moving loading of laser Gao Si heat source is realized by using parameterized language (APDL). The finite element models of single-channel and multi-channel single layer and multi-channel are established, respectively, and the forming region is predicted. Based on the calculation results of the temperature field, the stress and strain field analysis model of the laser melting process is established by using the coupled thermodynamic method, and the thermal evolution law and residual stress distribution are analyzed, which provides the basis for the practical processing in the future.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34

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