Simultaneous single‐loop multimaterial and multijoint topology optimization

Abstract

Summary As the aerospace and automotive industries continue to strive for efficient lightweight structures, topology optimization (TO) has become an important tool in this design process. However, one ever‐present criticism of TO, and especially of multimaterial (MM) optimization, is that neither method can produce structures that are practical to manufacture. Optimal joint design is one of the main requirements for manufacturability. This article proposes a new density‐based methodology for performing simultaneous MMTO and multijoint TO. This algorithm can simultaneously determine the optimum selection and placement of structural materials, as well as the optimum selection and placement of joints at material interfaces. In order to achieve this, a new solid isotropic material with penalization‐based interpolation scheme is proposed. A process for identifying dissimilar material interfaces based on spatial gradients is also discussed. The capabilities of the algorithm are demonstrated using four case studies. Through these case studies, the coupling between the optimal structural material design and the optimal joint design is investigated. Total joint cost is considered as both an objective and a constraint in the optimization problem statement. Using the biobjective problem statement, the tradeoff between total joint cost and structural compliance is explored. Finally, a method for enforcing tooling accessibility constraints in joint design is presented.

Multi-material topology optimization considering natural frequency constraint

“…Florea et al. developed a multi-material multi-joint topology optimization (MMTO-MJTO) methodology based on spatial gradient and SIMP interpolation to simultaneously couple MMTO and MJTO (Florea et al. , 2019).…”

Material interface control in multi‐material topology optimization using pseudo‐cost domain method

“…The proposed method was limited to two material MMTO and performed MMTO and joint optimization sequentially, where the process of material and joint optimization occurred in two independent loops. Florea et al 42 later proposed a novel methodology for performing simultaneous multi‐material and multi‐joint topology optimization, but was still restricted to only two materials.…”

Automated joining element design for high product variety in the manufacturing industry

“…They apply topology optimization to structures without predefining the joining locations. Furthermore, these methodologies can include the selection of joining technologies during optimization (e.g., [46]). However, these methodologies focus on single performance metrics, Introduction such as noise, vibration, and harshness (e.g., [47]) or stiffness (e.g., [18,48]).…”

“…Here, holistic approaches advocate for the integrative design of components and joints to ensure effectively manufacturable products (e.g., [30,107]). More concretely, the literature has presented various methodologies for partial aspects of joining elements, including joining technology selection (e.g., [40,108,109]) and the generation of joining locations (e.g., [18,46,50]). Moreover, modular product design can optimize product architectures, considering indices such as assembly complexity (e.g., [83]).…”

“…Additionally, these approaches consider the joining technology simultaneously [45]. Recent examples can be found in the studies of Florea et al [46], Woischwill and Kim [45], and Ambrozkiewicz and Kriegesmann [192].…”