School of Materials and Mineral Resources Engineering,
Engineering Campus,Universiti Sains Malaysia,
14300 Nibong Tebal,Penang, Malaysia
The aim of the present work is to develop and apply an energy-balance model similar to that outlined by Abrate in order to predict the impact response of a foam-based and honeycomb-based sandwich structures. The accuracy of the model will be investigated by varying the incident energy of the falling impactor as well as the properties of the foam core.
The impact response of the sandwich structures was modelled using an energy-balance model. Here, it is assumed that the target responds quasi-statically during the impact event and that the kinetic energy of the target is absorbed in bending, shear and contact effect deformations.
Energy balance model:
The wide applications of UHMWPE include bio-medical material for artiﬁcial joint replacement, engineering bearing, valves and automotive. Despite the suitability of UHMWPE for these applications, there are still challenges on the wear problem that occur in UHMWPE components, especially in bio-medical implant . To overcome this problem, UHMWPE composites were fabricated by adding reinforcing ﬁbres and particle ﬁllers. Wear and friction tests were performed using a pin-on-disc tester with a variable applied load sliding speed against 400-grit SiC abrasive paper counter face. Subsequently, the worn surfaces and the transfer ﬁlm formed were observed using scanning electron microscope (SEM).
Generally, there are many available techniques in studying dynamic mechanical properties of materials, which are reviewed by Hamouda and Hashmi. Among those techniques, the Split Hopkinson Pressure BarGenerally, there are many available techniques in studying dynamic mechanical properties of materials, which are reviewed by Hamouda and Hashmi. Among those techniques, the Split Hopkinson Pressure Bar technique (SHPB) is one of the most widely used for high strain rate testing . technique (SHPB) is one of the most widely used for high strain rate testing.
Fused deposition modelling (FDM) is one of the most widely used 3D printing techniques employed over the last few years in engineering and medical fields. This technology has enabled product customisation for small-scale production, with polymers still being the most widely used materials in the FDM process, especially acrylonitrile butadiene styrene (ABS). However, the application of FDM to produce parts and components is limited due to exhibiting lower mechanical properties as compared to other conventional means. Apart of that, the issue related with biocompatibility is one of the most important things that need to be considered when utilising the technology for biomedical application. The conventional FDM material such as ABS, is associated with toxicity due to to the styrene content in its chemical structure, which is anticipated to cause cancer in humans. Although no evidence has been established to prove that ABS is a toxic substance, it is well known this material has not satisfying the medical device biocompatibility requirements.
In this context, traditional pure material feedstocks are no longer satisfy all the requirements for the biomedical application and thereby, there is a real need for an improved material such as by making a polymer composite by using a suitable type of biocompatible polymer, while at the same time exhibits outstanding performance in mechanical properties. In this project, polyamide 12 incorporated with bioceramic fillers was utilised to improve the mechanical properties in respect with conventional pure polyamide. The outcomes for the present study show the feasibility of development of new polyamide 12 composites for biomedical application. Incorporation small amount of fillers between 10-30 wt% in the PA12 matrix resulted in either an improvement or a maintenance of the mechanical properties, especially those related to the strength and modulus.
Schematic diagram of 3D printing process starts from designing, setting the parameters, slicing to G-code and printing.
A representative of tensile specimen after printing process
Rahim, T. N. A. T., Abdullah, A. M., Akil, H., Mohamad, D., & Rajion, Z. A. (2017). The improvement of mechanical and thermal properties of polyamide 12 3D printed parts by fused deposition modelling. Express Polymer Letters 11, 963–982.
Tuan Rahim, T. N. A., Abdullah, A. M., Akil, H., Mohamad, D., & Rajion, Z. A. (2015). Preparation and characterization  Tuan Rahim T.N.A., Abdullah A.M., Akil H., Mohamad D. and Rajion Z.A. : Preparation and characterization of a newly developed polyamide composite utilising an affordable 3D printer. Journal of Reinforced Plastics & Com. Journal of Reinforced Plastics & Composites 34, 1628–1638.