# A Comparative Study of the Application of Different Commercial Software for Topology Optimization
###### Abstract  
Topology optimization (TO) has been a popular design method among CAD designers in the last decades. This method optimizes the given design domain by minimizing/maximizing one or more objective functions, such as the structure's stiffness, and at the same time, respecting the given constraints like the volume or the weight reduction. For this reason, the companies providing the commercial CAD/FEM platforms have taken this design trend into account and, thus, have included TO in their products over the last years. However, it is not clear which features, algorithms, or, in other words, possibilities the CAD designers do have using these software platforms. A comparative study among the most applied topology optimization software was conducted for this research paper. First, the authors developed an online database of the identified TO software in the form of a table. Interested CAD designers can access and edit its content, contributing in this way to the creation of an updated library of the available TO software. In addition, a deeper comparison among three commercial software platforms--SolidWorks, ANSYS Mechanical, and ABAQUS--was implemented using three common case studies--(1) a bell crank lever, (2) a pillow bracket, and (3) a small bridge. These models were designed, optimized, and validated numerically, as well as compared for their strength. Finally, the above software was evaluated with respect to optimization time, optimized designs, and TO possibilities and features. t 20221 2022  
A practical representation of the TO workflow in a TO software platform is shown in Figure 2.  
In Figure 2, the TO is divided into two main tasks--pre-processing and post-processing. On the one hand, the pre-processing of the design consists of the design phase, the implementation of the finite element method (FEM) with the definition of the mathematical model, and the discretization of the design space into finite elements. This task is concluded with the presentation and evaluation of the results. At this point, the computer-aided design (CAD) designer has to decide if there is room for optimization, which optimization method should be followed, and which TO software can satisfy his/her needs. On the other hand, post-processing is the second task where the optimized designs are prepared for production either by conventional production methods (CPM) or additive manufacturing (AM). Thus, during the TO workflow, there are many decisions that have to be taken, referred to as the CAD designer's inputs. These inputs can be classified into four clusters--the design constraints, the supports and connections, the loads, and the geometric restrictions  
Figure 1: The different types of SO adapted from [5]. Figure 2: A common TO workflow adapted from [11]. due to manufacturing constraints [12]. The design constraints are all the geometrical dimensions that form the size and shape of the CAD model. The supports and connections restrain the degrees of freedom of the model. In other words, they define the relationship between the model and its environment, such as its interaction with other components. The loads are all the load cases that a CAD designer has to take into account in the optimization task. Finally, the geometric restrictions due to manufacturing constraints can be considered a subcase of the design constraints with a focus on the manufacturability of the CAD model. Different restrictions should be taken into account in the case of CPM compared to AM. In addition to these four clusters, a fifth cluster could be added regarding the properties and features of the TO software. The first numerical method of TO was a 99-line script by Sigmund [13]. This can be considered the first form of a TO software platform and the kernel of many optimization platforms. The script was written in MATLAB and is based on the solid isotropic material with penalization method (SIMP) [2; 14].