Browsing by Author "Mouti, Zakaria"
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Item Open Access The effect of temperature changes on to quasi-static tensile and flexural performance of glass fibre reinforced PA66 composites(Cranfield University Press, 2013-09-19) Butterworth, Ian; Abhyankar, Hrushikesh; Westwood, Keith; Njuguna, James; Brighton, James; Mouti, ZakariaA significant method of reducing CO2 emissions in road vehicles is to reduce the vehicle mass. One means in which this can be achieved is to adopt lightweight materials such as thermoplastic composites. Thermoplastics offer advantages in term of weight when compared to conventional steel and aluminium casting. In this study thermal mechanical testing has been conducted on two types of commercial polyamide 66 (PA66) with 35 wt.% short glass fibre reinforcement. One of the materials was impact modified with an elastomer to increase material toughness. Experimental results showed both the reinforced PA66 materials to be temperature dependent. All test results demonstrated the trade-off in the mechanical properties of the two materials especially the impact modified. PA66 with 35 wt.% short glass fibre exhibits the best tensile strength, flexural strength and modulus for each temperature tested. Whereas the impact modified PA66 with 35 wt.% short glass fibre exhibits the higher strain and toughness for each temperature tested.Item Open Access Finite element analysis of glass fiber-reinforced polyamide engine oil pan subjected to localized low velocity impact from flying projectiles(2012-10-31T00:00:00Z) Mouti, Zakaria; Westwood, Keith; Long, Darren; Njuguna, James A. K.This paper investigates low velocity impact involving a glass fiber-reinforced polyamide engine oil pan as part of a complete new development of thermoplastic components. The assessment of the impact resistance has driven the need to employ LS DYNA for finite element modeling in order to benchmark and predict the strength and fracture behavior of stressed plastic parts. In order to develop a reliable predictive capability and to validate simulations, complete components were manufactured by injection molding techniques for the experimental samples. Low velocity impact investigations were carried out using a gas gun and a falling weight tester in order to simulate impact events to which the oil pan is subjected whilst in operational service. This was intended to point out damage tolerance and failure mechanisms likely to occur in the structure. The study results show the significant contribution of the design in terms of shock absorption. Specific oil pan design with protective ribbing combined with a superior material considerably improves the impact resistance. The paper provides results and discussions on experimental and finite element analysis investigations before concluding with some remarks.Item Open Access Finite element analysis of localised impact loading on short glass fibrereinforced polyamide engine oil pan subjected to low velocity impact from flying projectiles(2011-05-24T00:00:00Z) Mouti, Zakaria; Westwood, Keith; Long, Darren; Njuguna, James A. K.This paper investigates low velocity impact involving a glass fibre-reinforced polyamide engine oil pan as part of a complete new development of thermoplastic components. The assessment of the impact resistance has driven the need to employ LS DYNA for finite element modelling in order to virtually benchmark and predict the strength and fracture behaviour of stressed plastic parts. In order to develop a reliable predictive capability and to validate simulations, complete components were manufactured by injection moulding techniques for the experimental samples. Low velocity impact investigations were carried out using a gas gun and a falling weight tester in order to simulate impact events to which the oil pan is subjected whilst in operational service. This was intended to point out damage tolerance and failure mechanisms likely to occur in the structure. The study results show the significant contribution of the design in terms of shock absorption. Specific oil pan design with protective ribbing combined with a superior material considerably improves the impact resistance. The paper provides results and discussions on experimental and finite element analysis investigations before concluding with some remarks.Item Open Access Localised low velocity impact performance of short glass fibre reinforced polyamide 66 oil pans(Cranfield University, 2012-03) Mouti, Zakaria; Njuguna, JamesThis thesis focuses on the mechanical properties of short glass fibre reinforced polyamide 66 material used in automotive composite structures, and its impact resistance under localised low velocity impact. The main application of this research concerns the impact performance of an oil pan component susceptible to stone impact damage. The thesis reviews the current state-of-the-art of thermoplastic polyamide materials with an overview of the glass fibre reinforced polyamide under-the-hood components, as well as its manufacturing and processing techniques. The study explores much of the work published in the literature so as to identify the fundamental parameters determining the impact resistance. It then concentrates on assessing the mechanical properties of the material subjected to quasi-static loads and impacts considering the influence and consequences of atmospheric or weathering conditions such as the moisture and salt uptake and the variation of temperature. The experimental work employed a universal testing machine for the quasi-static tests, drop weight tower and projectile air gun to carry out the dynamic tests. The testing involves different polyamide grades and impact modifier material in small specimens and full-scale oil pan components so as to gain important insights into the material-geometrical coupling effects. In correlation with the experiments, a finite element analysis was conducted to predict capability and simulate impact events using LS-DYNA solver. The simulation allowed putting to the test and comparing different protective design features. The post-testing investigations focused on the damage assessment and failures at micro- and macro-scales on the structure using visual inspection, scanning electron microscopy and ultrasound flaw detector. This was intended to bring detailed understanding of the failure mechanisms and also shed some light into damage tolerance of typical under-the-hood thermoplastic polyamide components. Investigation results indicated that impact resistance properties of short glass fibre reinforced polyamide 66 grades are sensitive and influenced by moisture and salt uptakes, temperature ageing and air oxidation. In general, the increase of these parameters reduces the material strength but at the same time improves its strain. The study also compares different structures and shows the significant contribution of the design in terms of shock absorption and stress distribution. The proposed oil pan design with protective ribbing pattern combined with a superior material with rubbery phase considerably improves the impact resistance of the full-scale automotive component studied.Item Open Access Low Velocity Impact Behavior of Glass Filled Fiber-Reinforced Thermoplastic Engine Components(MDPI AG, 2010-03-31T00:00:00Z) Mouti, Zakaria; Westwood, Keith; Kayvantash, Kambiz; Njuguna, James A. K.This paper concerns automotive parts located underneath the engine and in particular the engine oil pan. Classically made of stamped steel or cast aluminum, new developments have allowed the manufacture oil pans with polyamide 66 reinforced by 35% weight of short glass fiber. However, polyamides have some limitations and the most significant is their response to localized impact loading. The nature of the impact considered here is of a typical stone collected from the road and projected into the oil pan. Low velocity impact investigations were carried out using a gas gun and drop weight tower. The study shows that the design of the oil pan has a significant contribution in the shock absorption. In addition to the material properties, the geometry and the ribbing both cleverly combined, increase the impact resistance of the component significantly. Areas of oil pan design improvement have been identified and conclusions drawn.