Development of a methodology for the characterization of long-fibre composite materials for crashworthiness applications using CAE

Composite materials have received a great deal of attention in recent years because of their exceptional mechanical properties and light weight, which make them suitable for a variety of engineering applications. One of these applications is crashworthiness, which refers to the ability of a structure to absorb energy during a crash, thus protecting occupants and minimising damage to the vehicle. In this context, the development of a methodology for the characterisation of long fibre composite materials using computer-aided engineering (CAE) is of vital importance. The use of CAE tools has revolutionised the process of design and analysis of engineering structures, offering significant advantages such as cost and time savings, increased accuracy and the ability to simulate complex loading scenarios. By harnessing the power of CAE, engineers can perform virtual testing and analysis of composite structures, enabling a better understanding of their behaviour and performance under crash conditions. The goal of this research is to develop a comprehensive methodology for the characterisation of long fibre composite materials specifically tailored to crashworthiness applications. The methodology will include experimental tests previously performed in-house, together with numerical simulations using CAE techniques. By combining these two approaches, a comprehensive understanding of the material behaviour and its response to shock loading can be achieved. The characterisation process will involve the selection of suitable composite materials, taking into account factors such as fibre type, matrix material and fibre volume fraction, which are known to significantly influence the mechanical properties of the composite. Experimental tests were used to obtain essential material properties such as tensile strength, compressive strength, shear strength and fracture toughness. These properties will serve as input data for the numerical simulations. The CAE simulations will be carried out using the finite element method (FEM), which allows virtual modelling and simulation of complex structures. By creating an accurate representation of the composite structure and applying realistic loading conditions, the material response can be predicted. The developed methodology will be validated with experimental results. This validation process is crucial to ensure the accuracy and reliability of the methodology. Any discrepancies between experimental and simulated results will be analysed.Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructur

Life Cycle Energy Assesment of Advanced Fiber Reinforced Composite Design and Manufacturing Methodologies

Automotive industry at large is focused on vehicle light-weighting since a 6%-8% increase in fuel efficiency can be achieved with a 10% reduction in vehicle weight [1]. With the growing demand for cost-effective and sustainable light weighting of automobile structures, interest has increased in the application of fiber reinforced plastic (FRP) composites for use in the Body-in-White (BiW), which can account for up to 40% of the total vehicle weight. Traditional FRP composite manufacturing processes like vacuum assisted resin transfer molding, autoclave consolidation or use of automated fiber placement have been successfully used for marine and aerospace applications. However, these processes are not suitable for the automotive industry due to the low production rate, need for highly skilled labor for manufacturing and quality control, and poor joining with traditional structural materials like steel. This necessitates the use of higher throughput outof-autoclave (OOA) processes like high pressure resin transfer molding (HP-RTM), wet compression molding (WCM) or even fiber reinforced thermoplastics (FR-TP) forming. The transition to these OOA processes face two major challenges: a) the time-consuming iterative design and thermal profiling process required for metal tools which increases cost; and b) the lack of a low-cost, scalable, and sustainable multi-material joining pathways that can enable integration of FRP composite parts with traditional metal structures. This is because existing composite joining methods necessitate significant redesign of existing OEM infrastructure, incur high capital costs, and produce weak joints between metal and composite components. iii To address the first challenge, a new paradigm where additive manufacturing of thermoplastic filament reinforced with continuous fiber is used to develop a low-cost and sustainable composite tool, is investigated. Furthermore, additive manufacturing can enable faster tool design turn-around times and allows for designing of complex tool geometries with embedded sensors and conformal cooling channels. This opens greater avenues for process and design optimization and will enable manufacturers to gain a better understanding of the process based on sensor data gathered in real time from the embedded sensors. To address the later challenge, a highly integrated multi-material, FRP-intensive BiW design was developed using unique multi-material transition joints which retain existing OEM joining infrastructure [2]. It incorporates multi-material transition joints where continuous dry fibers are laid through machined looped channels in a metal substrate and additional metal layers are additively manufactured on top of the looped fiber and metal substrate to embed the fibers within the metal and create a strong metal – fiber mechanical interlocking bond. The fibers are then infused with a thermoset matrix that fills out the loops as well, forming a string FRP-metal transition [3]. Thus, the resulting CFRP component with metal tabs can be spot welded to other metal components without piercing, drilling, or punching holes - significantly increasing the mechanical performance of the multi-material joints. To ascertain the advantages of these multi-material designs and the use of state-of-the-art additively manufactured smart tools, their life cycle impact must be investigated and compared with existing technology. The results from the LCA can provide vital understanding of the energy requirements of the new processes methodologies and can help iv quantify the benefits offered by transitioning to this new proposed paradigm of composite design and manufacturing from a sustainability and emission reduction standpoint. To best of the authors knowledge there have been no studies that address the LCA for each of the proposed solutions. Thus, this work, conducts two comparative life cycle analyses on the proposed additively manufactured smart composite tool for OOA processes and for the multi-material designs for automotive structural components. Different scenarios are studied for both the LCAs to consider the existing FRP production processes as well as the production process of traditional materials

Vehicle lightening with composite materials: Objective performance comparison of material-systems for structural applications

In recent years many studies proved that the adoption of polymer composites represents an effective solution to reduce the weight of vehicles. In this context, the goal of this study is the design of a rear suspension cradle made of composite material, with particular attention to aspects such as recyclability and high volume production of the component. Starting from the CAD model of the existing aluminum part, a simplified shape that represented it was designed and FEM analysis was conducted using the software ABAQUS; materials, geometry and fiber orientation were changed in order to obtain a composite model with the same performance as the aluminum model but with lower weight. The performance of the composite and aluminum models were compared. In addition, a manufacturing process and a method of recycling for the optimal composite model solution were provided

Environmental and cost analysis of carbon fibre composites recycling

While carbon fibre reinforced plastic (CFRP) can reduce transportation energy use and greenhouse gas emissions by reducing vehicle weight, the production of virgin carbon fibre (CF) itself is energy intensive. CFRP recycling and the reutilisation of the recovered CF have the potential to compensate for the high impact of virgin CF production due to low cost and to open up new composites markets – e.g., in the automotive sector. The aim of the research is to examine the life cycle environmental and financial implications of a fluidised bed process to recycle CFRP wastes and to identify potential markets for CFRP reuse in automotive applications. Firstly, process models of the fluidised bed carbon fibre recycling technologies are developed based on thermodynamic principles and established modelling techniques to quantify the heat and electricity requirements and predict the energy efficiency of a hypothetical commercial-scale plant. The energy model shows that the energy requirement of recycled CF production is generally less than 10% relative to virgin CF and results are robust across likely operating conditions. Further optimisation of the fluidised bed recycling process is needed to balance to the feed rate per unit bed area to minimise process energy use and potential implications for recycled CF properties. Opportunities exist for recovering stack heat loss which could further improve the energy efficiency of the fluidised bed process. Secondly, process models for recycled CF processing (i.e., wet-papermaking/ fibre alignment) and subsequent CFRP manufacture (i.e., compression moulding/ injection moulding) technologies are developed to quantify the energy and material requirements of a hypothetical operating facility. Models are based on optimised parameters based on the best performance from previous experiments, where available, while target values are used for the fibre alignment technologies currently under development. Thirdly, the life cycle environmental implications of recovering carbon fibre and producing composite materials as substitutes for conventional materials (e.g., steel, aluminium, virgin CFRP) are assessed and proposed as lightweight materials in automotive applications, based on process models of the fluidised bed recycling process and remanufacturing processes or available life cycle assessment databases. Life cycle impact assessments demonstrate the environmental benefits of recycled CFRP compared with end-of-life treatment options (landfilling, incineration). Recycled CF components can achieve the lowest life cycle environmental impacts of all materials considered, although the actual impact is highly dependent on the design criteria of the specific components. Low production impacts associated with recycled carbon fibre components are observed relative to lightweight competitor materials (e.g., aluminium, virgin CFRP). Recycled CF components also have low in-use fuel consumption due to mass reduction and associated reduction in mass-induced fuel consumption. The results demonstrate the potential environmental viability of recycled CF materials. Finally, financial analysis of carbon fibre recycling, processing, and use in recycled CFRP materials is undertaken to assess potential market opportunities in the automotive sector. Cost impacts of using recycled CF as a substitute for conventional materials are also assessed in the full life cycle, making use of data from energy and cost models, manufacturers and existing cost databases. Recovery of CF from CFRP wastes can be achieved at $5/kg and less across a wide range of process parameters. CFRP materials manufactured from recycled CF can offer cost savings and weight reductions relative to steel and competitor lightweight materials in some cases, but are dependent on the specific application and associated design constraints– e.g., the material design index - as this drives the weight reduction/in-use fuel consumption and material requirements. Fibre alignment could potentially improve financial performance by inducing larger vehicle in-use fuel cost savings associated with weight reductions. Further investigations to monetise environmental impacts show larger cost benefits for recycled CFRP materials in replacement of conventional steel and lightweight competitor materials

Environmental and cost analysis of carbon fibre composites recycling

While carbon fibre reinforced plastic (CFRP) can reduce transportation energy use and greenhouse gas emissions by reducing vehicle weight, the production of virgin carbon fibre (CF) itself is energy intensive. CFRP recycling and the reutilisation of the recovered CF have the potential to compensate for the high impact of virgin CF production due to low cost and to open up new composites markets – e.g., in the automotive sector. The aim of the research is to examine the life cycle environmental and financial implications of a fluidised bed process to recycle CFRP wastes and to identify potential markets for CFRP reuse in automotive applications. Firstly, process models of the fluidised bed carbon fibre recycling technologies are developed based on thermodynamic principles and established modelling techniques to quantify the heat and electricity requirements and predict the energy efficiency of a hypothetical commercial-scale plant. The energy model shows that the energy requirement of recycled CF production is generally less than 10% relative to virgin CF and results are robust across likely operating conditions. Further optimisation of the fluidised bed recycling process is needed to balance to the feed rate per unit bed area to minimise process energy use and potential implications for recycled CF properties. Opportunities exist for recovering stack heat loss which could further improve the energy efficiency of the fluidised bed process. Secondly, process models for recycled CF processing (i.e., wet-papermaking/ fibre alignment) and subsequent CFRP manufacture (i.e., compression moulding/ injection moulding) technologies are developed to quantify the energy and material requirements of a hypothetical operating facility. Models are based on optimised parameters based on the best performance from previous experiments, where available, while target values are used for the fibre alignment technologies currently under development. Thirdly, the life cycle environmental implications of recovering carbon fibre and producing composite materials as substitutes for conventional materials (e.g., steel, aluminium, virgin CFRP) are assessed and proposed as lightweight materials in automotive applications, based on process models of the fluidised bed recycling process and remanufacturing processes or available life cycle assessment databases. Life cycle impact assessments demonstrate the environmental benefits of recycled CFRP compared with end-of-life treatment options (landfilling, incineration). Recycled CF components can achieve the lowest life cycle environmental impacts of all materials considered, although the actual impact is highly dependent on the design criteria of the specific components. Low production impacts associated with recycled carbon fibre components are observed relative to lightweight competitor materials (e.g., aluminium, virgin CFRP). Recycled CF components also have low in-use fuel consumption due to mass reduction and associated reduction in mass-induced fuel consumption. The results demonstrate the potential environmental viability of recycled CF materials. Finally, financial analysis of carbon fibre recycling, processing, and use in recycled CFRP materials is undertaken to assess potential market opportunities in the automotive sector. Cost impacts of using recycled CF as a substitute for conventional materials are also assessed in the full life cycle, making use of data from energy and cost models, manufacturers and existing cost databases. Recovery of CF from CFRP wastes can be achieved at $5/kg and less across a wide range of process parameters. CFRP materials manufactured from recycled CF can offer cost savings and weight reductions relative to steel and competitor lightweight materials in some cases, but are dependent on the specific application and associated design constraints– e.g., the material design index - as this drives the weight reduction/in-use fuel consumption and material requirements. Fibre alignment could potentially improve financial performance by inducing larger vehicle in-use fuel cost savings associated with weight reductions. Further investigations to monetise environmental impacts show larger cost benefits for recycled CFRP materials in replacement of conventional steel and lightweight competitor materials

Study on feasibility and viability of applying eco-friendly material for the “be”-car bonnet for a sustainable automotive part

The usage of plastic parts and metals parts in automotive industries is causally related to the negative impact on the environment. The fact behind using plastic auto parts is that they give the same strength as metal parts in minimal weight. However, the plastic parts are nonbiodegradable, and the extraction of mineral ores lead to the polluted environment, physical landscape disturbances, and substantial harms. Thus, this research is to find an alternative solution for such kind of problems. To begin with, attempts were performed in order to analyze the feasibility and viability of using natural fiber composites for a semi-structural or small structural auto part. In this study, the part to be studied is an automotive bonnet. Two significant parts comprise the bonnet system, the skin and the supporting frame. The objective is to replace the plastic/metal bonnet skin with an NFRP (Natural Fiber Reinforced Plastic) so that the part can be sustainable and eco-friendly. The bonnet is one of the critical components in an automobile. They have to fulfill many pedestrian safety requirements in order to successfully be certified by the NCAP, apart from being an engine cover. This research is concerned about the bonnet of a new car called “Be”, which CEIIA is developing for a sustainable automotive future. Based on brief studies on the bonnet system, the NFRPs, and the safety requirements for the bonnet system, the use of sustainable materials and corresponding manufacturing process selection was carried out. Using the selected material, a composite laminate is manufactured using a suitable manufacturing process to produce a sustainable and eco-friendly composite. To answer many of the significant questions such as strength and the sustainability of the composite part, various mechanical testing and numerical simulations were performed and checked with the requirement matrix. Two kinds of the recycling process are carried out, and the composite was successfully recycled to prove its sustainability. This investigation has been performed as a “CEIIA - Product Development Project,” and as a master thesis for “Instituto Superior de Engenharia do Porto,” during February-October 2018

Experimental and numerical investigation of mechanical effect of externally weak layers in thick hybrid composites

There is a growing interest in the use of thick hybrid composite laminates in the structural elements of aerospace and hydrospace structures. As amount of composite materials used in aircraft structures has now exceeded 50% by weight, it is more crucial than ever to study their mechanical properties and failure behaviors. In the present work, the influence of weak external layers of carbon and glass fibers on the flexural behavior of thick carbon/glass fiber reinforced hybrid composite laminates was examined to monitor their failure mechanisms. In the first part, four types of symmetric laminate structures were designed by tailoring the stacking sequence of glass (G) and carbon (C) fiber reinforced prepregs. Hot Press Curing (HPC) technique was utilized for manufacturing of the laminates. In each composite structure, 48 prepreg plies were used; and their configurations were adjusted to (C8/G8/G8)s, (G8/C8/G8)s, (G8/G8/C8)s, and (C8/G8/C8)s. Flexural tests showed that the highest flexural strength (1260 MPa) was exhibited by the laminate with the configuration of (G8/C8/G8)s, and the highest flexural modulus (79.64 GPa) was shown by the laminate with configuration of (C8/G8/C8). In addition, Digital Image Correlation (DIC) technique was used for the full-field in-plane strain and displacement registration, and for the study of failure mode development during the bending tests. The results indicated that the type of fiber placed along the horizontal midplane of the laminate controlled the failure mode, and the type of fiber available on the faces governed the behavior of stress strain curve. The fracture surface characterization performed by optical and scanning electron microscopy techniques indicated that the compressive failures in the form of kink band formation and shear-driven interlaminar delamination were the two most prevalent forms of failure in thick hybrid laminates. In parallel to the experimental study, numerical study was carried out by Finite Element Method (FEM) to investigate the displacement values in the direction parallel and transverse to the loading axis, and for obtaining the longitudinal and shear strain values. Both experimental and numerical studies emphasized the importance of using stacking sequence of a thick hybrid laminate as a practical approach in controlling the flexural properties of the composites. To conclude, this work provides a new insight into the design and fabrication of thick-section hybrid laminates by the adjustment of their stacking sequenc

Develop a bladder assisted RTM tool to manufacture seat posts with glass fiber and CNT-epoxy resin

In this project, a bladder-assisted Resin Transfer Moulding tool to manufacture glass fiber bicycle seat posts with epoxy resin charged with carbon nanotubes (CNTs) is developed through the application of a "Systematic Approach to the design of Technical Systems and Products" guideline to provide an optimum solution for the filtering of CNTs during the injection process. The impregnation process is identified as the key characteristic on the tool development. The bladder assisted-RTM process parameters and manufacturing seat post features are evaluated to define the requirements that fulfill the main task, a homogeneous distribution of CNTs through the fiber glass reinforcement. According to the requirements, the task is divided in function and subfunctions to be fulfilled by the tool development. Interfaces between sub-functions are established in order to re-organize them into realizable modules. This module structure showed a preliminary indication for the breakdown of solution into realizable groups or elements, and together with their interfaces facilitated an efficient distribution of design effort. Tool constituent elements are designated and multiple principle solutions are provided for every element. Once selected the most adequate individual solution, a tool concept design is presented and begins the layouts development for the individual modules (Housing shape, Cooling system, Front cover with compressed air connection, Rear cover with resin injection port, Rear cover with airextraction exhaust, closing device, centering of the tool components, gaskets for the tightness and bladder as core design). Detailed drawings and calculations are performed to confirm that the design solution meets the requirements of the general task. The impregnation concept process using the inflatable bladder designed is explained, showing the collapsible channel operation in order to infuse correctly the braided glass fiber reinforcement using the high viscosity resin due the CNTs addition. At the end of the project, manufacturing tests are done to select the inflatable bladder with three different elastic materials using a reduced tool. After bladder material selection, a real scale tool is designed and constructed to manufacture a simple inflatable bladder, as first approach to the final bladder manufacturing. For the bladder manufacturing, a real scale bladder dipping mandrel is manufactured using water soluble fugitive core material.Ingeniería Técnica en Mecánic