Question
Hello our professor wants us to know why did they use the Solid178 geometry in page 3 in their research and why is it good can you please help me it's really important
of the knee joint [2]. Finite Element Analysis of the human knee joint can help extensively in determining the underlying causes of cartilage degeneration which in turn results in osteoarthritis. John et al. [3] focused on the imaged-based techniques for development of solid model of human knee joint for finite element analysis. The main focus was to determine the effect of changes in the properties of menisci on the stress and strain distribution in the knee joint. Lagrou [4] studied the sequential procedure to be followed in the finite element analysis of the human knee joint. Pena et al. [5] and Bae et al. [6] developed the 3D finite element model of the knee joint to determine the contact behaviour of the knee joint. The soft tissues of the knee joint, namely the cartilages, menisci and ligaments, are particularly susceptible to wear owing to high levels of contact stresses [7]. The main objective of this study is to perform the 3D reconstruction of a healthy knee joint from an MRI scan to determine the contact stresses in the knee joint using finite element analysis. Methodology The MRI of the right knee of a healthy 22-year-old subject with no history of osteoarthritis was obtained. The MRI of the knee joint was performed under full extension. The knee joint comprises bones (femur, tibia, fibula and patella), cartilages (femoral cartilage, medial tibial cartilage, lateral tibial cartilage and patellar cartilage), menisci (medial meniscus and lateral meniscus), ligaments (medial collateral ligament and lateral collateral ligament, anterior cruciate ligament and posterior cruciate ligament) and tendons (quadriceps tendon and patellar tendon) Each of the parts is reconstructed individually from the MRI scans using Mimics Research v18.0 Fig.1 depicts the contour segmentation process in Mimics for the femur. Fig.2 shows the different mask regions in the complete assembly of the knee joint. The anatomical correctness of the models was ensured by referring to the literature and verified with the help of a radiologist. The 3D surface meshed models generated by Mimics contain a large number of triangles with high aspect ratios. Fig.1. Contour segmentation process in Mimics software for femur NAFEMS India Regional Conference Bangalore, 30-31st August 2016
Explanation / Answer
Researcher have used solid 178 geometry because:
1. As, bone, cartilage in organism are irregular meshes in structure and solid 178 geometry is the best method to model irregular meshes.
2. Each element in solid 178 geometry has plasticity, creep , hyperplasiticity and structure like bone, menisci , cartilage are assumed to have these property.
