scholarly journals Topology Optimization Considering Porosity Defects in Metal Additive Manufacturing

2021 ◽  
Vol 11 (12) ◽  
pp. 5578
Author(s):  
Shuangyuan Cao ◽  
Hanbin Wang ◽  
Xiao Lu ◽  
Jianbin Tong ◽  
Zhongqi Sheng
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Level Set ◽  
Optimization Model ◽  
Optimization Method ◽  
Topological Sensitivity ◽  
Classical Level ◽  
Porosity Defects ◽  
Two Phases ◽  
Metal Additive

In this paper, considering the porosity defects of Additive Manufacturing (AM), a level set topology optimization method for AM with porosity constraints is proposed. The concept of topological sensitivity is used to formulate a global porosity constraint function in the proposed method, and a level set topology optimization model considering porosity defects is obtained. To improve the robustness of the algorithm, the topology optimization model is solved in two phases. At first, the classical level set method without the porosity constraint is used to initially optimize the structure. During this process, the hole nucleation method combining bi-directional evolutionary structural optimization (BESO) and the topological sensitivity is used. Secondly, the topology optimization considering the effects of porosity is implemented on the preliminary optimization results. After performing the two-step optimization, a robust structure that alleviates the harmful impact of porosity defects is obtained. Finally, the robustness and effectiveness of the proposed method are validated by several two-dimensional numerical examples.

scholarly journals A Hole Nucleation Method Combining BESO and Topological Sensitivity for Level Set Topology Optimization

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2119
Author(s):  
Shuangyuan Cao ◽  
Hanbin Wang ◽  
Jianbin Tong ◽  
Zhongqi Sheng
Keyword(s):  
Topology Optimization ◽  
Level Set ◽  
Volume Ratio ◽  
Optimization Method ◽  
Sensitivity Threshold ◽  
Design Domain ◽  
Topological Sensitivity ◽  
Classical Level ◽  
Evolutionary Structural Optimization ◽  
Beso Method

As is known to all, the incapacity to nucleate holes automatically in the design domain is one of the main issues of the classical level set topology optimization method. To solve the issue of hole nucleation, this paper employs the bi-directional evolutionary structural optimization (BESO) method based on the material removal scheme and the frequently used topological sensitivity and proposes the combining BESO and topological sensitivity (CBT) method for level set topology optimization. This method can replace the existing hole nucleation method for level set topology optimization. First, the topological sensitivity is combined with BESO, and the BESO method based on topological sensitivity is proposed. Second, the method is integrated into level set topology optimization to solve the issue of hole nucleation. Two sensitivity thresholds are defined depending on the evolutionary volume ratio and boundary topological sensitivity, respectively, and the smaller one is used as the sensitivity threshold for hole nucleation. The material is removed from the design domain to nucleate holes based on this threshold. Three classical two-dimensional numerical examples are used to validate the proposed hole nucleation method.

Parametric Topology Optimization Toward Rational Design and Efficient Prefabrication for Additive Manufacturing

2017 ◽  
Author(s):  
Long Jiang ◽  
Hang Ye ◽  
Chi Zhou ◽  
Shikui Chen ◽  
Wenyao Xu
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Level Set ◽  
Manufacturing Process ◽  
Rational Design ◽  
Optimization Method ◽  
Significant Advance ◽  
Original Design ◽  
Computational Framework ◽  
Multi Scale

The significant advance in the boosted fabrication speed and printing resolution of additive technology has considerably increased the capability of achieving product designs with high geometric complexity. The prefabrication computation has been increasingly important and is coming to be the bottleneck in the additive manufacturing process. In this paper, the authors devise an integrated computational framework by synthesizing the parametric level set-based topology optimization method with the DLP-based SLA process for intelligent design and additive manufacturing of not only single material structures but also multi-scale, multi-functional structures. The topology of the design is optimized with a new distance-regularized parametric level set method considering the prefabrication computation. offering the flexibility and robustness of the structural design that the conventional methods could not provide. The output of the framework is a set of mask images which can be directly used in the additive manufacturing process. The proposed approach seamlessly integrates the rational design and manufacturing to reduce the complexity of the computationally-expensive prefabrication process. Two test examples, including a freeform 3D cantilever beam and a multi-scale meta-structure, are utilized to demonstrate the performance of the proposed approach. Both the simulation and experimental results verified that the new rational design could significantly reduce the prefabrication computation cost without affecting the original design intent or sacrificing original functionality.

Optimal Viscous Damper Placement Using Level Set Topology Optimization Method

2010 ◽  
Author(s):  
Masoud Ansari ◽  
Amir Khajepour ◽  
Ebrahim Esmailzadeh
Keyword(s):  
Topology Optimization ◽  
Level Set ◽  
Discrete Optimization ◽  
Optimization Problem ◽  
Minimum Energy ◽  
Optimization Method ◽  
Discrete Optimization Problem ◽  
Placement Problem ◽  
New Approach ◽  
Optimal Damping

Vibration control has always been of great interest for many researchers in different fields, especially mechanical and civil engineering. One of the key elements in control of vibration is damper. One way of optimally suppressing unwanted vibrations is to find the best locations of the dampers in the structure, such that the highest dampening effect is achieved. This paper proposes a new approach that turns the conventional discrete optimization problem of optimal damper placement to a continuous topology optimization. In fact, instead of considering a few dampers and run the discrete optimization problem to find their best locations, the whole structure is considered to be connected to infinite numbers of dampers and level set topology optimization will be performed to determine the optimal damping set, while certain number of dampers are used, and the minimum energy for the system is achieved. This method has a few major advantages over the conventional methods, and can handle damper placement problem for complicated structures (systems) more accurately. The results, obtained in this research are very promising and show the capability of this method in finding the best damper location is structures.

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