Response surface methodology integrated modeling of glass fiber reinforced polymer delamination in high speed drilling

Extensive research efforts has been made in the conventional drilling of glass fiber reinforced polymer, where most researches focused in the studies of drilling parameters and thrust force relationship to delamination and tool wear. The effect of drilling generated heat was suggested frequently in these studies, but not many in-depth researches was done in this area. In this paper, an experiment was performed to study the effects of thrust force and drilling generated temperature generated from drilling parameters on delamination factor. A response surface method (RSM) integrated model consist of two phases was developed. The first phase of RSM modelling explained the relationship of drilling parameters with thrust force and drilling generated heat as mediator. The relationship between the mediator and the delamination factor were developed in the second phase of RSM modeling. The final RSM integrated models were validated and it resulted in a low percentage error delamination factor estimation equation from drilling parameters, while understanding and controlling the thrust force and drilling generated temperature

Progressive Crushing of Polymer Matrix Composite Tubular Structures: Review

The present paper reviews crushing process of fibre-reinforced polymer (FRPs) composites tubular structures. Working with anisotropic material requires consideration of specific parameter definition in order to tailor a well-engineered composite structure. These parameters include geometry design, strain rate sensitivity, material properties, laminate design, interlaminar fracture toughness and off-axis loading conditions which are reviewed in this paper to create a comprehensive data base for researchers, engineers and scientists in the field. Each of these parameters influences the structural integrity and progressive crushing behaviour. In this extensive review each of these parameters is introduced, explained and evaluated. Construction of a well-engineered composite structure and triggering mechanism to strain rate sensitivity and testing conditions followed by failure mechanisms are extensively reviewed. Furthermore, this paper has mainly focused on experimental analysis that has been carried out on different types of FRP composites in the past two decades

Buckling strength improvements for Fibre Metal Laminates using thin-ply tailoring

The buckling response and load carrying capacity of thin-walled open cross-section profiles made of Fibre Metal Laminates, subjected to static axial compression loading are considered. These include thin-walled Z-shape and channel cross-section profiles adopting a 3/2 FML lay-up design, made of 3 aluminium layers. The objective of the investigation is the comparison of standard thickness Fibre Reinforced Plastic layers versus thin-ply material technology. Whilst thin ply designs differ only by the layer thickness, they offer an exponential increase in stacking sequence design freedoms, allowing detrimental coupling effects to be eliminated. The benefit of different hybrid materials are also considered. The comparisons involve semi-analytical and finite element methods, which are validated against experimental investigations

Drilling characteristics and properties analysis of fiber reinforced polymer composites: A comprehensive review

Fiber-reinforced polymer (FRP) composites play a vital role in the production of structural and semi-structural components for engineering applications. The drilling process is a commonly employed machining process for FRP composites to join the FRP structural elements. Usually, the FRP composites possess a heterogeneous nature because of their multi-layered structure, hybridization, and the presence of multi-phase materials. Hence, common problems like delaminations, fuzzing, buckling, cracking, matrix and fiber burning occur during the drilling operations. These problems cause dimensional inaccuracy, poor surface finish, and tool wear and reduce the mechanical strength of the composites. The optimum drilling parameters (drill geometry, speed, feed, and depth of cut) selection for the specific materials is good to achieve effective drilling performance and better surface quality of the holes. Yet, little study has been done on how all of these factors affect the size of the drilled hole. The majority of drilling studies on FRPCs in the past have focused on how to improve the hole quality by maximizing processing conditions, and there has been little discussion on the correlation between drilling conditions, physical properties, and production techniques. This is what motivated to review the characteristics and properties analysis of FRP composites. As a consequence of this research, it is anticipated that scientists and researchers would place a greater emphasis on the drilling characteristic of the workpieces made from FRPCs than on other attributes. This review clearly presents an overview of FRP composites drilling that had progressed from 2000 to 2021. The analysis of different drilling conditions and parameters like thrust force, drill geometry, temperature, speed, and feed also includes the post-drilling analysis through delaminations, thermal damage, and surface roughness. Furthermore, the recent developments in carbon, glass, and natural fiber reinforced polymer composites are studied with both conventional and nonconventional drilling techniques. Based on the above studies, some future challenges and conclusions are drawn from this review

Multi-Response Optimization in Drilling of MWCNTs Reinforced GFRP Using Grey Relational Analysis

The present work concentrates on the use of Grey Relational Analysis for optimizing the drilling parameters like weight percentage of multi-wall carbon-nanotube (MWCNTs), cutting speed and feed rate on the thrust force and the delamination factor in the drilling of GFRP composites. Full factorial design is utilized for the trial. Analysis of variance (ANOVA) is applied to determine the significance of drilling parameters on multi-response. Considering the multi-response optimization results, which are acquired from the largest Grey Relational Grade (GRG), it is determined that optimal parameters are 1 wt. % MWCNTs, cutting speed 25 m/min, and feed rate 0.10 mm/rev to minimize concurrently thrust force and delamination factor. It is provided that the percentage development in GRG with the multi-response optimization is 50.53%. It is clearly indicated that the quality characteristics are crucially developed using this approach in the drilling of GFRP. According to the results of ANOVA of the GRG, the crucial factor is feed rate. Validation experiment was confirmed by computing the confidence level within the interval width. Eventually, results of validation experiment with the optimum drilling conditions settings have indicated that the proposed model develops overall performance of drilling process

Microstructural investigation and hole quality evaluation in S2/FM94 glass-fibre composites under dry and cryogenic conditions

International audienceS2/FM94 glass fibre reinforced epoxy is an aerospace-grade composite currently bonded with aluminium alloys and installed in parts of the Airbus A380 fuselage. In addition to its abrasive and hard nature, S2/FM94 glass fibre is sensitive to thermal effects developed during the drilling process, and therefore using coolants becomes necessary. However, conventional oil and water-based coolants are not suitable for drilling of composites. Cryogenic coolants on the other hand are an attractive choice for machining composites and are environmentally friendly. In this study, a new environmentally friendly cryogenic cooling technique in a liquid nitrogen bath was used for the drilling of S2/FM94 glass fibre reinforced epoxy composite. The aim was to investigate the effect of drilling parameters and cryogenic cooling on cutting forces, surface roughness, hardness and delamination factor at hole entry and exit sides. The workpiece was drilled within a cryogenic bath. In this way, both cryogenic workpiece cooling and tool cooling were obtained. In addition, the drill geometry is fixed and only the cutting parameters (i.e. spindle speed and the feed rate) are varied under dry and cryogenic conditions. The results indicate that the spindle speed and cryogenic cooling had the most significant influence on the cutting forces and surface roughness parameters (R a and R z ), while the use of cryogenic cooling had the most significant influence on increasing the hardness and size of delamination at entry and exit sides of the holes

Recent advances in drilling of carbon fiber–reinforced polymers for aerospace applications: a review

Drilling is considered as one of the most challenging problems in aerospace structures where stringent tolerances are required for fasteners such as rivets and bolts to join the mating parts for final assembly. Fiber-reinforced polymers are widely used in aeronautical applications due to their superior properties. One of the major challenges in machining such polymers is the poor drilled-hole quality which reduces the strength of the composite and leads to part rejection at the assembly stage. In addition, rapid tool wear due to the abrasive nature of composites requires frequent tool change which results in high tooling and machining costs. This review intended to give in-depth details on the progress of drilling of fiber-reinforced polymers with special attention given to carbon fiber–reinforced polymers. The objective is to give a comprehensive understanding of the role of drilling parameters and composite properties on the drilling-induced damage in machined holes. Additionally, the review examines the drilling process parameters and its optimization techniques, and the effects of dust particles on human health during the machining process. This review will provide scientific and industrial communities with advantages and disadvantages through better drilled-hole quality inspection

Multi-objective optimization in machining of GFRP and MMC composites: two case experimental research

Composite materials like GFRP and MMCs having more importance in various manufacturing industries mainly in aerospace and automotive industries and many engineering application, because of their unique mechanical properties as compare to the conventional material. Drilling is the most common machining process in manufacturing industries for assembly of components but drilling of composite may possesses many difficulties such as fiber pull out, delamination and circularity etc. which affects the quality of drilled hole. To overcome these difficulties the effect of machining parameters on different machining responses should be investigated for attaining high product quality as well as satisfactory machining process performance. Therefore, the main objective of this dissertation is to investigate the various machining performance characteristics with different machining condition in drilling of GFRP and MMCs composites by using various integrated multi objective optimization methodologies. In this presented thesis, Deng’s similarity method integrated with Taguchi, TOPSIS integrated with Taguchi method (in drilling of GFRP composite) and PCA-Grey method integrated with Taguchi, Grey-TOPSIS Integrated with Taguchi method (in drilling of MMCs), have been implemented for obtaining the optimal machining conditions

Drilling of Glass Fiber Reinforced Polymer (GFRP) Composites: Multi Response Optimization Using Grey Relation Analysis with Taguchi’s Method

Nowadays, GFRP (Glass Fiber Reinforced Polymer) composites are widely used in manufacturing industries specially aircraft, aerospace, and automobile industries due to their excellent mechanical and thermal properties such as more specific strength, better specific modulus of elasticity, high damping factor or damping capacity, better resistance to corrosion, effective fatigue resistance, low thermal expansion coefficient. Hence, it is necessary to understand the machinability behavior of these composites. Drilling is widely used to assemble the components in aforementioned industries. But machining of these composites is dissimilar to conventional metals due to their isotropic nature and in-homogeneity. Major drawbacks of these composites in machining are fiber pull out, delaminating and burring of fibers. So, appropriate selection of process parameters is an important concern in machining of GFRP composites. This work mainly focuses on assessing the effects of process parameters i.e. spindle speed, feed and drill diameter on thrust, torque, delamination factor (both at entry and exit) in drilling of GFRP composites using TiAlN coated drill bit. The study also utilizes the Grey methodology coupled with Taguchi L16 OA to determine the optimal parametric combination

Optimization for drilling process of metal-composite aeronautical structures

Metal-composite laminates and joints are applied in aircraft manufacturing and maintenance (repairing) using aluminum alloys (AA) and glass fiber-reinforced polymer (GFRP). In these applications, drilling has a prominent place due to its vast application in aeronautical structures’ mechanical joints. Thus, this study presents the influence of uncoated carbide drills (85C, 86C, H10N), cutting speeds (vc = 20, 40, and 60 m min−1), and feed rates (f = 0.05, 0.15, and 0.25 mm rev−1) on delamination factor, thrust force ( Ft), and burr formation in dry drilling metal-composite laminates and joints (AA2024/GFRP/AA2024). Experiments were performed, analyzed, and optimized using the Box–Behnken statistical design. Microscopic digital images for delamination evaluation, piezoelectric dynamometer for thrust force acquisition, and burr analysis were considered. The major finding was that the thrust force during drilling depends significantly on the feed rate. Another significant factor was the influence of the drill type (combined or not with feed rate). In fact, it was verified that the feed rate and the drill type were the most significant parameters on the delamination factor, while the feed rate was the most relevant on thrust force. The cutting speed did not affect significantly thrust force and delamination factor at exit (FdaS). However, the combination f × vc was significant in delamination factor at entrance (FdaE). Based on the optimized input parameters, they presented lower values for delamination factors (FdaE=1.18 and FdaS=1.33) and thrust force ( Ft=67.3N). These values were obtained by drilling the metal-composite laminates with 85C-tool, 0.05 mm rev−1 feed rate, and 20 m min−1 cutting speed. However, the burrs at the hole output of AA2024 were considered unsatisfactory for this specific condition, which implies additional investigation