A self-supporting microstructure topology optimization method considering overhung angles and minimum size constraints

Abstract

The invention belongs to the technical field related to structural optimization design, and discloses a self-supporting microstructure topology optimization method considering overhung angles and minimum size constraints. The method comprises the following steps: (1) initializing relative unit density of micro-structure, material volume fraction, material attribute parameter and optimization algorithm parameter; (2) projecting the relative unit density of the microstructure to a density constrained by a cantilever angle and a minimum size, and obtaining a displacement field of the microstructure; (3) obtaining the equivalent elastic tensor of the microstructure, and carrying out sensitivity analysis on the topology optimization model of the microstructure, and then constructing an optimization criterion to update the relative unit density of the microstructure; (4) judging whether the current relative cell density satisfies the iterative convergence condition, and if so, outputting theoptimal microstructure configuration; Otherwise go to step (2). The invention does not depend on engineering experience, has high flexibility, and ensures that the microstructure has self-supportingproperty and also has better macroscopic equivalent performance.

Description

technical field [0001] The invention belongs to the related technical field of structure optimization design, and more specifically relates to a self-supporting microstructure topology optimization method considering cantilever angle and minimum size constraints. Background technique [0002] The forming principle of additive manufacturing technology is "layer-by-layer manufacturing", that is, parts are formed by accumulating materials layer by layer, so highly complex structures can be processed and formed. However, in the additive manufacturing process, there are still unique manufacturing constraints, such as 1. The minimum size constraint of the structure. In the additive manufacturing process, no matter whether the fusion deposition modeling process, selective laser sintering process or selective laser melting process is used, The minimum size of the formable structure is inevitably affected by the diameter of the nozzle or the width of the laser beam, so the minimum fe...

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Problems solved by technology

However, in the additive manufacturing process, there are still unique manufacturing constraints, such as 1. The minimum size constraint of the structure. In the additive manufacturing process, no matter whether the fusion deposition modeling process, selective laser sintering process or selective laser melting process is used, The minimum size of the formable structure is inevitably affected by the diameter of the nozzle or the width of the laser beam, so the minimum feature size of the structure cannot be smaller than the manufacturing accuracy of the additive manufacturing equipment, otherwise the structure containing the minimum feature size cannot be manufactured

2. The cantilever angle constraint of the structure. In the process of additive manufacturing, the model is sliced ​​by software and printed layer by layer. This requires that there be materials under each part of the sliced ​​model, otherwise a "castle in the air" will be formed. Cause collapse during the printing process; the structure of the "castle in the air" is described by the physical quantity of the overhang angle, and the model containing the structure with a large overhang angle needs to be processed in the process of additive manufacturing. The usual processing method is in the model Artificially add support structures to the large cantilever angle structure. These support structures are processed as part of the model and removed after forming. This not only increases the cost of raw materials and time, but also damages the model after post-processing. surface quality

This type of method adds too many artificial constraints and engineering design experience to the design of the self-supporting structure, relies on experience, and obtains poor macro-equivalent performance of the self-supporting microstructure.

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