Purpose

This study aims to introduce a novel approach in form of a comprehensive software suite to help understanding and optimizing the build orientation toward maximizing the fatigue lifetime of complex geometries. The objective is to find an optimized build orientation under a given in-service loading state, which brings on smoother surfaces in stressed regions, mitigated roughness-induced stress concentration and deferred crack initiation stage. The solution addresses scenarios that no post-build surface treatment can be applied.

Design/methodology/approach

To account for the surface topography, the staircase induced surface roughness is registered as a function of build angle using the white light interferometry characterization, based on which the stress concentration factor (k_t) is calculated. Thereafter, the developed module in “Fatlab toolbox” is used to find the optimum build angle, considering the integrated surface orientations and stress analysis under a given loading condition.

Findings

Surface topography creates local stress concentrations upon loading, directly influencing the fatigue lifetime. It is a well-established fact that the conditions of the staircase geometry and surface roughness affect the magnitude of the stress concentration upon loading, which is influenced by the build orientation of the component. The proposed solution suggests the best build orientation that mitigates staircase-related surface roughness.

Originality/value

The suggested numerical approach assists the designers with positioning of the part on the build plate to minimize the build orientation-induced surface roughness and improve the as-built fatigue lifetime of the component.

中文翻译：

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一种新颖的方法，用于提高通过增材制造技术处理的组件的疲劳寿命

目的

这项研究旨在以一种综合软件套件的形式介绍一种新颖的方法，以帮助理解和优化构造方向，从而最大限度地延长复杂几何形状的疲劳寿命。目的是找到在给定的在役载荷状态下的优化构造方向，该方向在应力区域中使表面更平滑，减少粗糙度引起的应力集中并延缓裂纹萌生阶段。该解决方案解决了无法应用构建后表面处理的情况。

设计/方法/方法

为了解决表面形貌问题，使用白光干涉测量特性将阶梯引起的表面粗糙度记录为倾斜角度的函数，然后根据该角度计算应力集中系数（k _t）。此后，在给定的载荷条件下，考虑到集成的表面方向和应力分析，使用“ Fatlab工具箱”中开发的模块来找到最佳的构建角度。

发现

表面形貌在加载时会产生局部应力集中，直接影响疲劳寿命。公认的事实是，楼梯几何形状和表面粗糙度的条件会影响加载时的应力集中的大小，这受部件的构造方向影响。提出的解决方案建议了最佳的构建方向，可以减轻与楼梯相关的表面粗糙度。

创意/价值

建议的数值方法可帮助设计人员将零件定位在构建板上，以最大程度地减少构建方向引起的表面粗糙度，并改善组件的实际疲劳寿命。