Abstract. This study is an approach to investigate the environmental impact of screw manufacturing and to choose suitable material for selected screw-making processes for the best performance with minimum environmental impact. The parameters involved were types of material and screw-making process using the environmental data available in Asia region. The two different manufacturing approaches being evaluated were machining and forging. The types of material considered were low carbon steel, stainless steel, titanium alloy and aluminium alloy. As for machining process, the materials being considered in screw manufacturing were low carbon steel, stainless steel, titanium alloy, aluminium alloy, magnesium alloy and cast iron. The information of environmental impact are generated by SolidWorb. Sustainability tool was used in the formation of pair-wise comparison matrices for Analytic Hierarchy Process (AHP). Then, the ranking of global priorities had enabled the determination of appropriate material to be used for those selected screw manufacturing process. As a result, aluminium alloy was found to give minimum environmental impact for forging process whereas cast iron was found to excel in machining process. At the same time, titanium alloy was not suggested to be used in either process.
Abstract. This paper presents numerical analysis of stress intensity factors (SIFs) of inclined cracks due to mechanical mismatches. According to literature survey, tremendous amounts of SIFs can be found elsewhere. However, the SIFs for inclined cracks are difficult to obtain especially when mechanical mismatch at the crack interface are considered. ANSYS finite element program is used to model the cracks embedded in plain strain plates. The cracks are oriented at the interface between two different materials and subjected to mode I tension loading. It is showed that when mechanical mismatches are introduced the mode I SIFs reduced and on the other hand mode II SIFs increased. When the cracks are inclined, the mode I SIFs diverged but it is not for mode II SIFs and gradually increased when compared with the normal cracks.
Packaging materials for logistical purposes are designed to protect electrical and electronic products and other fragile consumer goods from damages due to shock and excessive vibrations during handling and transportation. There is recently an increased concern for the development of not only well-designed but also sustainable materials. Material sustainability is often associated with the extraction of renewable resources and disposal procedures that would not damage our ecosystem. In this respect, indigenous agro-waste resources would be a smart alternative to fabricate lightweight and disposable greenmaterials at low cost. This paper highlights some of the key utilities or functions of packaging materials and the commercially available packaging materials in the market at present. The prospect of biodegradable materials including indigenous natural fibers and an example of completely compostable commercial packaging material are outlined. Preliminary results of shock cushioning test on (surface-modified) kenaf filled polypropylene composites prepared in this study indicated that the 20% optimum content was the best cushioning are presented.
Pulley-based continuously variable transmission (CVT) with a metal pushing V-belt is fast becoming the preferred choice for global carmakers due to its potential particularly in terms of fuel efficiency thanks to its continuous and wide ratio range. Nevertheless, the existing CVTs still face the issues of high power consumption from the engine because of the application of an electro-hydro-mechanical (EHM) actuation system for its ratio changing process and clamping force mechanism. To address this issue, researchers from Universiti Teknologi Malaysia have successfully developed the prototype of an electro-mechanical dual-acting pulley continuously variable transmission (EMDAP CVT) for automotive applications. The prototype of EMDAP CVT is developed for a maximum input torque of 160 Nm with the application of a metal pushing V-belt. The results from the testing prove that the prototype can vary its ratio from 2.8 to 0.6 and no continuous power is required to maintain a constant CVT ratio. These results suggest that the prototype is workable and future testing in a real car is possible.
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