Session: IMECE Undergraduate Research and Design Exposition

Paper Number: 121089

121089 - An Integrated Computational Framework for Process-Informed Analysis of 3d Printed Knee Assembly Components 

    Numerical simulations have emerged as a vital component for enhancing the effectiveness of manufacturing processes in industry. Among these transformative innovations is additive manufacturing (AM), a technique that utilizes computer-aided design (CAD) data to deposit materials layer by layer, resulting in the creation of complex 3D geometries.

    AM is a favorable manufacturing technique because of its minimal waste and lightweight ability. AM supports various materials, including polymers, ceramics, and metals, which can be used depending on the specific application. Additionally, the layer by layer technique allows for the machining of an intricate topography to be constructed with minimal waste, which would not be as easily achieved with traditional machining methods. This method of manufacturing is attractive for the medical industry, specifically for prostheses, because of the ability for patient-specific prosthetic design. Currently, standard implants come in prefabricated sizes and the surgeon's judgment is necessary to achieve an ideal fit during surgery. Integrating AM and finite element analysis (FEA) into the process would enable prostheses fabrication tailored to the specific needs of the individual patient. This process also minimizes the amount of bone cuts needed for correct fitting and additional future surgical adjustments. As the use of AM applications grows, the need for tolerancing standards specific to AM is necessary. Due to the shape distortions and complex geometry, traditional standards for tolerancing are not applicable. Thus, a method of function-oriented tolerancing must be developed.

    The objective of this research is to develop an integrated computational framework for function-oriented tolerancing in the additive manufacturing of 3D freeform objects with arbitrary geometries. This study focuses on simulations of a knee implant as a model example; however, the framework can be applied to any complex geometry. The simulation model is obtained from an open-source CAD assembly of a total knee replacement. The additive manufacturing scenario app in 3DEXPERIENCE software is then employed to simulate the 3D-printing process of two typical components in the knee assembly, the femur and the femoral. The results of this thermo-mechanical simulation predict the part distortions and residual stresses that arise from the nature of the AM printing process. This can be used to determine critical areas for failure of 3D-printed knee implants under in-service loading conditions. The next step is to simulate both components of the femur and femoral in an assembly under clinical loading conditions for tolerancing analysis. Both the ideal components (as-designed CAD model) and the 3D-printed components (with part distortions and residual stresses) are simulated in their respective assemblies for comparison. The assembly includes contact interactions between the two components to be considered, with process-informed part distortions and residual stresses further subjected to in-service loading and boundary conditions. A comparison between the two cases of the ideal and AM process-informed components shows a significant increase in stress level under in-service loading for the latter case, which will aid in function-oriented tolerancing analysis of 3D-printed components in future work.

Presenting Author: Chloe Shirikjian University of Massachusetts Dartmouth

Presenting Author Biography: Chloe Shirikjian is a senior undergraduate student at the University of Massachusetts Dartmouth, where she is pursuing a bachelor’s degree in mechanical engineering. Her academic journey sparked an interest in various topics within the field, including additive manufacturing and renewable energy. In the summer of 2023, she had the privilege of being awarded the MA Space Grant Fellowship. This enabled her to engage in additive manufacturing research under the mentorship of a group of professors and their student research team. Chloe aims to continue her academic journey at UMass Dartmouth, where she plans to enroll in the accelerated mechanical engineering master’s degree program. She aspires to finish her degree by the summer of 2025 to then work in industry or research.

Authors:

Chloe Shirikjian University of Massachusetts Dartmouth
Wenzhen Huang University of Massachusetts Darmouth
Alfa Heryudono University of Massachusetts Dartmouth
Jun Li University of Massachusetts Dartmouth