Shah Fenner Khan Mohamad Khan
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Preferred name
Shah Fenner Khan Mohamad Khan
Official Name
Shah Fenner Khan, Mohamad Khan
Alternative Name
Khan, S. F.
Khan, S. F.K.Mohamad
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Scopus Author ID
57197729639

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Fabrication of mandible fracture plate by indirect additive manufacturing

2017-10-29 , Muhammad Aizat Abu Bakar , Shah Fenner Khan Mohamad Khan

Bone fracture is a serious skeletal injury due to accidents and fragility of the bones at a certain age. In order to accelerate fracture healing process, fracture bone plate is use to hold the fracture segment for more stability. The purpose of this study is to fabricate mandibular fracture plate by using indirect additive manufacturing methods in order to reduce time taken during bending and shaping the fracture fixation plate that conform to the anatomy of the fractured bone site. The design and analysis of the plates are performed using CATIA and ANSYS software. The 3D-CAD data were sent to an additive manufacturing machine (fused filament fabricated) to generate master pattern using PLA and the mould were fabricated using Plaster of Paris. A melt ZAMAK 3 was poured directly into the moulds, and left it until completely harden. 3point bending test was performed on the prototype plate using universal testing machine. Stress-strain curve shows the graph exhibited a linear relationship of stress-strain up to a strain value of 0.001. Specimens give a maximum yielding stress and then break before the conventional deflection. Since the maximum flexural stress and the breaking stress are far apart with a plateau stating at strain value of 0.003mm/mm in most specimens, the specimen's failure types are considered plastic failure mode. The average thickness and width are 1.65mm and 2.18mm respectively. The flexural modulus and flexural strength are 189.5GPa and 518.1MPa, respectively.

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Lightweight design of Knee-Ankle-Foot Orthotic Devices using Voronoi patterns for Additive Manufacturing

2023-01-01 , Shah Fenner Khan Mohamad Khan , Zaidan M.A. , Nur Liyana Tajul Lile

Traditionally fabricated knee-ankle-foot orthosis (KAFO) device that is used to aid in the mobility user is uncomfortable. Problems such as weight and enclosure in almost all the part of the leg make it strenuous and humid for the user to wear for a long time. Furthermore, in the traditional production method, it can take up to a week to fabricate. The aim of this study is to redesign the knee-ankle-foot-orthosis by using the application of topology optimization in order to reduce the material used on the product and to make it lightweight. The parameters of the KAFO were determined by using indirect method; similar to traditional method. The modelling and analysis of the KAFO is completed by using CAD and CAE software. Optimization of the product is performed by redesigning the shape and applying topology optimization function. It is able to reduce the maximum stress of the product by 22.56% and the volume by 4.33%. Application of the Voronoi pattern further reduces the mass of the KAFO and produces more organic looks to the product. SLS Lisa Pro 3D printer is used to produce the KAFO in a period of less than a week. This prove to be a viable alternative for producing customized KAFO.

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Analysis and evaluation of optimized lower limb prosthetic device

2021-10-25 , Shah Fenner Khan Mohamad Khan , Noor Z.N.M. , Rani A.M.A.

Transtibial prosthetic devices or below-knee prosthetic devices are used as assistive devices in replacing the part of the leg below the knee joint in case of amputation. The different builds in amputees require the need for the accessibility to custom-made lucrative prosthetic devices in order to reintegrate the amputees into society. The goal of this study is to design a personalized transtibial prosthetic device that closely mimics the human gait by the use of topology optimization. Additive manufacturing is used to reduce the fabrication time of a traditional transtibial prosthetic device. The creation of the transtibial prosthetic device model is through computer-aided drawing (CAD) and afterwards simulated using ANSYS for the comparison and contrasting of the optimized design. The materials used in the design of the transtibial prosthetic device are polypropylene and titanium alloy. Simulation works reveal that there is a 12.8% reduction in the minimum equivalent (von-Mises) stress and a 51.29% reduction in the minimum equivalent elastic strain of the benchmark socket, and titanium alloy is the superior material in the fabrication of prosthetic foot as it greatly reduced the total deformation, equivalent (von-Mises) stress and equivalent elastic strain of the SACH foot as compared to polypropylene in the initial contact, midstance and the push-off phases of the gait cycle. Topology optimization of both the socket and foot models reduced the stiffness and density of material volume up to 60%. Voronoi pattern developed on the socket and foot models mirrors the reduction done on material volume by topology optimization.

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Development of new formulation for soft material in paste extrusion-based 3D Printer

2023-01-01 , Shah Fenner Khan Mohamad Khan , Baharudin M.M. , Nur Liyana Tajul Lile

Fused Deposition Modelling is a form of additive manufacturing where solid filament is heated into molten state and deposited onto a heating platform to create three-dimensional objects layer-by-layer. Since heating and cooling processes are involved in Fused Deposition Modelling (FDM), this restricts the use of thermoplastic polymers such Room Temperature Vulcanizing (RTV) silicones and gels. Others concern are with the right rheological properties for extrusion and the ability to provide desired mechanical qualities upon quick solidification. To develop a suitable silicone printing technology, it is crucial to understand the silicone polymerization mechanism in terms of its rheological and mechanical characteristics. Due to the numerous factors that can influence silicone paste mixtures, this study utilized the Taguchi method to design experiments, optimize factors, and predict properties, thereby avoiding extensive and resource-intensive experimental work. The study specifically considered the factors of curing method, mass ratio of silicone thinner, and fumed-silica in the silicone paste formulation. Among the 9 samples generated through the Taguchi method, only one sample demonstrated favourable results in terms of mechanical properties and the curing process, with a mixture ratio of base silicone, silicone thinner, and fumed-silica at 15g, <1g, 0.1g; respectively. However, further investigation into the fixed amount of silicone and fumed silica in the selected mixture ratio indicate that the amount of silicone thinner must be less than 1g or can be omitted as the silicone paste can be used as printing ink for the extruder. The shore hardness testing for the silicone samples revealed with zero percent silicone thinner exhibited a hardness value of 21.5 HA (Shore A) while the sample obtained less than 1g displayed a significantly lower hardness value of 10.5 HA. These findings indicate that the addition of silicone thinner in the silicone paste formulation, as optimized through the Taguchi method, contributed to a reduction in the hardness of the material for shore A scale. This suggests that the presence of silicone thinner affects the elasticity and flexibility of the silicone paste, resulting in a lower Shore hardness value. The discrepancy in hardness values between the samples further highlights the significance of formulation optimization to achieve desired material properties for silicone paste-based applications in 3D printing.

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