Total hip arthroplasty (THA) is most likely one of the most successful surgical procedures in medicine. It is estimated that three in four patients live beyond the first post-operative year, so appropriate surgery is needed to alleviate an otherwise long-standing suboptimal functional level. However, research has shown that during a complete THA procedure, a solid hip implant inserted in the femur can damage the main arterial supply of the cortex and damage the medullary space, leading to cortical bone resorption. Therefore, this study aimed to design a porous hip implant with a focus on providing more space for better osteointegration, improving the medullary revascularisation and blood circulation of patients. Based on a review of the literature, a lightweight implant design was developed by applying topology optimisation and changing the materials of the implant. Gyroid and Voronoi lattice structures and a solid hip implant (as a control) were designed. In total, three designs of hip implants were constructed by using SolidWorks and nTopology software version 2.31. Point loads were applied at the x, y and z-axis to imitate the stance phase condition. The forces represented were x = 320 N, y = −170 N, and z = −2850 N. The materials that were used in this study were titanium alloys. All of the designs were then simulated by using Marc Mentat software version 2020 (MSC Software Corporation, Munich, Germany) via a finite element method. Analysis of the study on topology optimisation demonstrated that the Voronoi lattice structure yielded the lowest von Mises stress and displacement values, at 313.96 MPa and 1.50 mm, respectively, with titanium alloys as the materials. The results also indicate that porous hip implants have the potential to be implemented for hip implant replacement, whereby the mechanical integrity is still preserved. This result will not only help orthopaedic surgeons to justify the design choices, but could also provide new insights for future studies in biomechanics.

Three-dimensional printing is widely used in many fields, including engineering, architecture and even medical purposes. The focus of the study is to obtain the ideal weight-to-performance ratio for making a 3D-printed part. The end products of the 3D-printed part are hugely affected by not only the material but also the printing parameters. The printing parameters to be highlighted for this study are the infill density, wall perimeter and layer height, which are the commonly adjusted parameters in 3D printing. The study will be divided into two parts, the simulation analysis and the experimental analysis, to confirm both results toward the trend of Young’s modulus for the material. It will then be analyzed and discussed toward any differences between the two results. The results showed that increasing the value of all three parameters will increase the tensile elasticity of the part.

This research reviews scissors lifts structure manufactured by AEREX, UMW Advantech Sdn. Bhd. that is used on a catering hi-lift using Finite Element Analysis (FEA). The scissors lifts is one of the major and crucial components of a catering hi-lift which is mainly used to hoist the van body of the catering hi-lift for aircraft servicing. The catering hi-lift is one of the aircraft ground support equipment that is commonly used to service commercial airliners. For the design to be approved by the Department of Safety and Health (DOSH) Malaysia under Hoisting Machine Design according to DS-149 Standard, it must comply with specific engineering design standard. The only standard applicable is the ANSI Standard MH29.1-2003 “Safety Requirements for Industrial Scissors Lifts” (Revision on ANSI MH29.1-1994). Focusing on the deflection accordance to the ANSI Standard; calculation regarding the allowable maximum deflection must not be exceeded. To analyze, manual calculations, solid modeling and computer simulations were involved using state-of-the-art CAE software. Several linear static FEA analyses were done to get accurate results. The results show that the deflection is still in the acceptable range. However, some manufacturers find that the allowable maximum deflection is too excessive. Therefore, advice on critical areas to the application must be given and other safety precautions must be taken to avoid failure during operation.

Femoral bone fracture is one of the main causes for the failure of hip arthroplasties (HA). Being subjected to abrupt and high impact forces in daily activities may lead to complex loading configuration such as bending and sideway falls. The objective of this study is to predict the risk of femoral bone fractures in total hip arthroplasty (THA) and resurfacing hip arthroplasty (RHA). A computed tomography (CT) based on finite element analysis was conducted to demonstrate damage formation in a three dimensional model of HAs. The inhomogeneous model of femoral bone was constructed from a 79 year old female patient with hip osteoarthritis complication. Two different femoral components were modeled with titanium alloy and cobalt chromium and inserted into the femoral bones to present THA and RHA models respectively. The analysis included six configurations, which exhibited various loading and boundary conditions, including axial compression, torsion, lateral bending, stance and two types of falling configurations. The applied hip loadings were normalized to body weight (BW) and accumulated from 1 BW to 3 BW. Predictions of damage formation in the femoral models were discussed as the resulting tensile failure as well as the compressive yielding and failure elements. The results indicate that loading directions can forecast the pattern and location of fractures at varying magnitudes of loading. Lateral bending configuration experienced the highest damage formation in both THA and RHA models. Femoral neck and trochanteric regions were in a common location in the RHA model in most configurations, while the predicted fracture locations in THA differed as per the Vancouver classification.

Interference screw fixation in Anterior Cruciate Ligament (ACL) reconstruction is a well known surgery to replace the damage or tear ligament of ACL with a graft made from tissue from other part of the body. The successive reconstruction and fixation strength is dependent on the bone quality and stability of the fixation as there is a potential damage to the graft due to screw threads. In this study, a finite element analysis is used to examine the effects of different screw materials in ACL reconstruction. The calculated mechanical behaviors are discussed with respect to the primary stability of screw fixation in ACL reconstruction. Three types of bio-absorbable materials are considered in the analysis namely poly-lactic acid (PLA), poly-lactic co-glycolic acid (PLGA) and poly-caprolactone (PCL). In addition, two metallic biomaterials are also included in the analyses which are titanium alloy and stainless steel. A 200 N tensile force is used as the loading condition directed on the interference screws at the femoral and tibial tunnels. It is the approximation of the graft tension at full extension during gait (level walking). Result shows that the maximum von-mises stress occurs on the interference screws are less than 40 MPa at the femoral and tibial fixation. A screw with stiffer material is identified to experience higher stress variation. The total displacement results show that the maximum displacements for all cases are less than 0.06 mm, which are small. The largest displacement is defined at less stiff material.