Finite Element Modeling of Stamp Forming Process on Thermoplastic-Based Fiber Metal Laminates at Elevated Temperatures

This paper investigated stamp forming performance of two aluminum-based Fiber-metal laminates (FMLs) with different fiber-reinforced composites using finite element analysis. Given the inherent thermal-dependent properties of fiber-reinforced polypropylene, the effect of elevated temperature on its forming behavior is worthy of concern. Furthermore, the elevation in temperature also influences the bonding within the constituent lamina. Both factors were integrated in the modelling. By investigating the through-thickness strain evolution throughout the stamping process, the forming mode of each layer, as well as their interactions, were better understood. Results suggested that the flow of matrix and the rotation at the intersections of fiber strands can be promoted at elevated temperature, which transforms the forming performance of FMLs close to that of monolithic aluminum. These results propose means to improve the forming performance of FMLs

EFFECT OF PROCESS PARMAETRS DURING FORMING OF SELF REINFORCED – PP BASED FIBER METAL LAMINATE

This research presents results on the stamp forming behavior of Fiber Metal Laminate Systems. A Design of Experiments approach was undertaken to elucidate the major effects of the process parameters that include blank holder force and temperature. Evolution of major strain and strain ratio were used as metrics in the analysis. A significant finding from this work is the identification of recrystallization behavior that significantly changed the forming behavior of this class of material systems

ECO-HYBRID COMPOSITE FAILURE BEHAVIOR OF TWO SERIAL BOLTED JOINT HOLES

This study investigates the geometrical effect of two serial bolted joint holes on hybrid composites. Geometry parameters studied were edge distance-to-upper hole centre (E/D) and the distance between centers of two holes diameter (K/D). The hybrid composites were fabricated using kenaf woven fiber and E-glass woven fiber. Composite specimens were manufactured through hot press molding compression method at 180oC. The bearing test was conducted according to ASTM D-5961 ‘Procedure C’. The results show bearing strength and failure mechanisms of hybrid composites highly depend on the geometry parameters. Hybrid composites with the highest geometrical parameter, K/D = 5 and E/D = 4, show the highest bearing strength (32.381 MPa) while hybrid composites with the lowest geometrical parameter, K/D = 2 and E/D = 2, exhibit the lowest bearing strength (20.445 MPa). Therefore, this indicates that bearing strength increases with increase of K/D and E/D ratio. The failure behaviors observed were shear-out modes, bearing modes and net-tension modes

APPLICATION OF TOTAL PRODUCTIVE MAINTENANCE TO REDUCE NON-STICK ON PAD PROBLEM IN IC PACKAGING

Focus improvement activity was employed to improve front-end assembly yield in integrated circuit packaging. The top three yield losses in parts per million (ppm) in front-end assembly were contributed by the following defects: non-stick on pad (NSOP) (2715 ppm), chip and crack (782 ppm) and missing wire (687 ppm). NSOP was due to floating die, bonded ball small in size, foreign matter on pad and glassifications. Floating die contributed 48% of the NSOP defect. Detailed explanation on how focus improvement activity used to reduce NSOP due to floating die is demonstrated. Upon identifying the root cause of die floating, which was due to no support and weakness in the vacuum system, actions were taken to eliminate and to control the identified causes. As a result NSOP due to floating die was reduced from 1300 ppm to 650 ppm, a reduction of 50% within one year

Performance Evaluation of Reworked Weld Joints

This study presents the performance evaluation of reworked welded joint that have weld imperfections which may result the strength of the structures. Tensile, bending and shear tests have been performed to evaluate the performance and reliability of reworked joint. Their effects on the quality and performance of the reworked welded joint are depend on the requirements of the structure in use. This study is providing detailed examination of the mechanical properties of the carbon steel reworked welded joint by using shielded metal arc welding (SMAW) techniques

Effect of carbon nanotubes loading in multifiller polymer composite as bipolar plate for PEM fuel cell

In this study, bipolar plates for Proton Exchange Membrane Fuel Cell (PEMFC) were developed by compression molding technique using Polypropylene (PP) as a polymer matrix and Graphite (G), Carbon Black (CB) and Carbon Nanotube (CNTs) as reinforcements. United Stated Department of Energy (US DOE) target values were taken as the benchmark for the development and investigation of the bipolar plate properties. The effects of CNTs loading on the electrical and mechanical properties of G/CB/PP composite were investigated. By adding small amount of CNTs such as 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 wt% into G/CB/PP composite thus will give synergy effects on electrical conductivity and mechanical properties. It was found that, using CNTs as a third filler at a loading of 6 wt% in a G/CB/PP composite, shown the higher result of in-plane electrical conductivity is 158.32 S/cm, the density and shore hardness 1.64 g/cm3 and 81.5 (SH) respectively. Meanwhile, the optimum value of flexural strength obtained was 29.86 MPa at 5 wt% of CNTs

APPLICATION OF FUZZY VIKOR IN AUTOMOTIVE BRAKE PAD MATERIAL

Multi Criteria Decision Making methods is one of the most common methods used to determine the most appropriate material. In the decision making process, there are dissimilarities to elicit, specify and analyse the information on alternatives, criteria and relative significance of the criteria. Fuzzy set has been utilised in Multi Criteria Decision Making methods to optimise the method and created an extended approach to deal with uncertainty and increase the accuracy of decision making. As for many years’ asbestos was viewed as having an optimal performance as a brake pad. However, this material has been banned by the Environmental Protection Agency. Due to the increasing awareness on environmental impact and subsequently the need towards sustainability, selection of the appropriate material for a brake pad that complies with the environment and regulations is vital and natural fibre reinforced composite has potential to replace the asbestos in the automotive brake pad application. Therefore, the objective of this study is to apply the Fuzzy VIKOR to select the best natural fibre reinforced composite for the automotive brake pad to replace the asbestos. Four alternatives of natural fibre reinforced composite with five criteria have been evaluated by three decision maker. The results of the Fuzzy VIKOR shows that the date palm fibre is selected as the best material for the automotive brake pad

Thermoplastic matrix selection based on entropy method for importance weight of criteria

The purpose of this study is to determine the importance weight of criteria for thermoplastic matrix selection that need to be considered in fibre metal laminate fabrication for car front hood using entropy method, where the information implied using the linguistic terms. The results showed that the tensile strength, impact strength and density are the essential criteria that need to be considered

Failure Analysis of Hybrid Fibre Reinforced Plastics for Bolted Joint under Thermal Effect

Composite material is gaining a large attention in these few years due to its high strength to weight ratio. The cost of composite is also relatively lower than conventional metallic alloy. Several previous studies had shown introducing of synthetic fibre in the natural fibre-based composite polymer can enhance the mechanical strength of the composite structure. This research paper studies the effect of temperature and preload moment on the bearing strength of woven kenaf-glass fibre reinforced polypropylene hybrid composite. The kenaf fibre and E-glass fibre are in the form of plain weave fabric. Composite specimens were manufactured through hot press moulding compression method at 180ºC. In bolted joint test, specimens were exposed to a temperature of 25ºC (room temperature), 40ºC, 50ºC, and 60ºC and tightened with 0Nm, 5.2Nm and 7.5Nm preload moment. Bearing response under different conditions was tested according to ASTM D5961 standard procedure and failure modes were observed. The results revealed that increase in the ambient temperature reduced the bolted joint strength whereas the increase in preload moment improved the joint strength

Development of feature recognition system for CAD/CAM integration

This paper presents a methodology for implementing the feature recognition system for achieving the Computer Aided Design/ Computer Aided Manufacturing (CAD/CAM) integration goals. The Featurebased modeling is being used to model the solid models. The features being considered in this paper is hole form feature. The input of the feature recognition system is the Standard for the Exchange of Product Model Data (STEP) files. The set of feature recognition rules is generated by using ruled based technique