Imprecise knowledge based design and development of titanium alloys for prosthetic applications

Imprecise knowledge on the composition–processing–microstructure–property correlation of titanium alloys combined with experimental data are used for developing rule based models for predicting the strength and elastic modulus of titanium alloys. The developed models are used for designing alloys suitable for orthopedic and dental applications. Reduced Space Searching Algorithm is employed for the multi-objective optimization to find composition, processing and microstructure of titanium alloys suitable for orthopedic applications. The conflicting requirements attributes of the alloys for this particular purpose are high strength with low elastic modulus, along with adequate biocompatibility and low costs. The ‘Pareto’ solutions developed through multi-objective optimization show that the preferred compositions for the fulfilling the above objectives lead to β or near β-alloys. The concept of decision making employed on the solutions leads to some compositions, which should provide better combination of the required attributes. The experimental development of some of the alloys has been carried out as guided by the model-based design methodology presented in this research. Primary characterizations of the alloys show encouraging results in terms of the mechanical properties

Physical, mechanical and abrasive wear behaviour of jute fiber reinforced polymer composites

Now-a-days, abrasive wear of engineering and agricultural machine components caused by the abrasive particles is a major industrial problem. Therefore, a full understanding of the effects of all system variables on the abrasive wear rates is necessary in order to undertake appropriate steps in the design of the machinery and the choice of materials to reduce/control wear. The need for the use of newer materials to combat wear situations has resulted in the emergence of polymer based system. Polymers and their composites form a very important class of tribo engineering materials and are invariably used in mechanical components where wear performance in non-lubricated condition is a key parameter for the material. The advantages of these materials are light weight, excellent strength to weight ratios, resistance to corrosion, non-toxicity, easy to fabricate, design flexibility, self-lubricating properties, better coefficient of friction, and wear resistance. The present research work is undertaken to study the physical, mechanical and three body abrasive wear behaviour of jute fiber reinforced polymer composites. Three different forms of jute fiber (short jute fiber, bidirectional jute fiber and needle punched nonwoven jute fiber) are considered for the present research work. Attempts have been made to explore the possible use of needle punched nonwoven jute fibers as reinforcement for polymer composites. The design of experiments approach using Taguchi methodology is employed for the parametric analysis of abrasive wear process. The study reveals that abrasive wear performance of needle punched nonwoven jute based composites is better than that of the short and bidirectional jute fiber reinforced composites. The morphology of abraded surfaces is examined by using scanning electron microscopy (SEM) and possible wear mechanisms are discussed. Finally, the ranking of the composite materials under study is done by using AHP-TOPSIS method based on their physical, mechanical and abrasive wear attributes

Investigation of key challenges facing aerogel composites development through multiscale approach

Error on title page. Date of award is 2022The aerogel particulate and fibre reinforced composites are becoming more and more popular due to their exceptional properties, nevertheless, they do face a range of challenges that need to be overcome for wider applications. The main ones include a lack of understanding of the interactions between aerogels and reinforcing fibre materials, lack of appropriate models to predict their performance, and finally, lack of property database, allowing for an informative selection of aerogel composites as a viable alternative to other materials. The primary goal of this work is to tackle those challenges and provide a better fundamental understanding of some cases of aerogel composites. In order to fulfil the thesis' goals, the aerogel influence on the various thermal and mechanical properties of epoxy and vinyl ester polymers were investigated. By incorporating various weight contents and sizes of silica and polyimide aerogel particles into these polymers, their thermal conductivity, compressive properties, and other thermomechanical properties in these particle-filled polymers have been evaluated. Overall, created composites presented a significant decrease in thermal conductivity, while the introduction of porous particles deteriorated composite mechanical response. Additionally, micromechanical testing of the interface between aerogel and fibre reinforcement has been performed for the first time to understand their bonding ability. By designing a method to deposit an aerogel droplet surrounding the fibre, the microbond tests were enabled, and the results revealed poor adhesion between aerogel and selected fibre type in general. In addition to the experimental part, this study also focused on modelling aerogels and aerogel composites, which provided insight into the interactions between aerogels and most common reinforcement materials using a multiscale approach. As a result, the nanoscale analysis using molecular dynamics allowed to estimate thermal and mechanical properties of low density silica and polyimide. What is more, the aerogel-fibre interfacial properties values have also been obtained though modelling. Finally, the microscale model was used to model the thermal and mechanical properties of epoxy composites. A close match between experimental and modelled thermal conductivity and compressive modulus of epoxy combined with low density silica or polyimide particles has been achieved by incorporating the nanoscale properties into the micromechanical model.The aerogel particulate and fibre reinforced composites are becoming more and more popular due to their exceptional properties, nevertheless, they do face a range of challenges that need to be overcome for wider applications. The main ones include a lack of understanding of the interactions between aerogels and reinforcing fibre materials, lack of appropriate models to predict their performance, and finally, lack of property database, allowing for an informative selection of aerogel composites as a viable alternative to other materials. The primary goal of this work is to tackle those challenges and provide a better fundamental understanding of some cases of aerogel composites. In order to fulfil the thesis' goals, the aerogel influence on the various thermal and mechanical properties of epoxy and vinyl ester polymers were investigated. By incorporating various weight contents and sizes of silica and polyimide aerogel particles into these polymers, their thermal conductivity, compressive properties, and other thermomechanical properties in these particle-filled polymers have been evaluated. Overall, created composites presented a significant decrease in thermal conductivity, while the introduction of porous particles deteriorated composite mechanical response. Additionally, micromechanical testing of the interface between aerogel and fibre reinforcement has been performed for the first time to understand their bonding ability. By designing a method to deposit an aerogel droplet surrounding the fibre, the microbond tests were enabled, and the results revealed poor adhesion between aerogel and selected fibre type in general. In addition to the experimental part, this study also focused on modelling aerogels and aerogel composites, which provided insight into the interactions between aerogels and most common reinforcement materials using a multiscale approach. As a result, the nanoscale analysis using molecular dynamics allowed to estimate thermal and mechanical properties of low density silica and polyimide. What is more, the aerogel-fibre interfacial properties values have also been obtained though modelling. Finally, the microscale model was used to model the thermal and mechanical properties of epoxy composites. A close match between experimental and modelled thermal conductivity and compressive modulus of epoxy combined with low density silica or polyimide particles has been achieved by incorporating the nanoscale properties into the micromechanical model

DESIGN AND ANALYSIS OF INTEGRALLY- HEATED TOOLING FOR POLYMER COMPOSITES

Almost all of chapters 4, 5 and 6 of the entire PhD thesis are published as: 1) Conference paper (Numerical Studies of Integrally-Heated Composite Tooling). Presented in ECCM16, 22-26 June 2014 Seville, Spain. 2) Journal paper (Numerical simulation and design optimization of an integrally-heated tool for composite manufacturing). Submitted 29 April 2014 to journal of Materials and Design for publication, Accepted 10 July 2014 and Available online 1 August 2014. 3) Journal paper (Numerical Simulation and Experimental Verification of Heating Performance of an Integrally Water-heated Tool). Submitted 16 September 2015 to journal of Reinforced Plastics & Composites, Accepted 23 November 2015 and Available online 28 January 2016. 4) Manuscript (Numerical Analysis of the Thermomechanical Behaviour of an Integrally Water-Heated Tool for Composite Manufacturing). Submitted for publication on 31-March-2016 in journal of Composite Structures. Manuscript ID: COST-D-16-00629.Tooling design is crucial for the production of cost-effective and durable composite products. As part of the current search for cost reduction (by reducing capital investment, energy use and cycle time), integrally-heated tooling is one of the technologies available for ‘out-of-autoclave’ processing of advanced thermoset polymer composites. Despite their advantages, integrally-heated tools can suffer from uneven distribution of temperature, variability in heat flow rate and inconsistency in heating/cooling time. This research, therefore, investigates a number of design variables such as shape and layout of heating channels in order to improve the heating performance of an integrally-heated tool. Design of Experiments (DoE) has been carried out using Taguchi’s Orthogonal Array (OA) method to set several combinations of design parameters. Each of these design combinations has been evaluated through numerical simulation to investigate heating time and mould surface temperature variation. The simulation results suggest that the layout of the channels and their separation play a vital role in the heating performance. Signal-to-Noise (S/N) ratio and analysis of variance (ANOVA) have been applied to the results obtained to identify the optimal design combination of the integrally-heated tool. Statistical analysis reveals that the heating performance of an integrally-heated tool can be significantly improved when the channels’ layout is parallel. The shape of the channels has negligible effect and the distance between the channels should be determined based on the production requirement. According to the predicted optimal design, a developed integrally water-heated tool is manufactured. The actual thermal properties of the constituent materials of the produced tool are also measured. Then a numerical model of the experimental tool model is simulated in ANSYS software, with setting the actual material properties and boundary condition to define the temperature uniformity and heating rate of the experimental tool. Comparison of the experimental and numerical results of the experimental tool confirmed the well assigning of the boundary conditions and material properties during simulation the heated tool. The experimental results also confirmed the predicted optimal design of the integrally heated tool. Finally, in order to define its thermomechanical behaviour under the effective (in service) thermal loads, a tool model is simulated. Numerical results presented that the produced extremes of thermal deformation, elastic strain, normal and plane shear stresses, under the effective thermal loading, are within the allowable elastic limits of the participated materials.Ministry of Higher Education and Scientific Research of Ira

Investigating the role of metallic fillers in particulate reinforced flexible mould material composites using evolutionary algorithms

To reduce the cooling time in soft tooling (ST) process, high thermal conductive fillers (such as metallic filler) are included in flexible mould material. But addition of metallic fillers affects various properties of ST process and the influences may vary according to the types of materials used. Therefore, in order to investigate the role of various metallic fillers in particulate reinforced flexible mould material composites, multi-objective optimizations of maximizing equivalent thermal conductivity and minimizing effective modulus of elasticity of composite mould materials are conducted using evolutionary algorithms (EAs). Here we have adopted two EA-based algorithms namely NSGAII and SPEA2 in order to solve the present problem independently. Comparative study of the results reveals that NSGAII performs better over SPEA2 for investigating the role of metallic fillers in particulate reinforced flexible mould material composites. A recently proposed innovization procedure is also used to unveil salient properties associated with the obtained trade-off solutions. These solutions are analyzed to study the role of various parameters influencing the equivalent thermal conductivity and modulus of elasticity of the composite mould material. Based on the findings through investigations, the optimal selection of materials is suggested including the cost implication factor

Proceeding Of Mechanical Engineering Research Day 2016 (MERD’16)

This Open Access e-Proceeding contains a compilation of 105 selected papers from the Mechanical Engineering Research Day 2016 (MERD’16) event, which is held in Kampus Teknologi, Universiti Teknikal Malaysia Melaka (UTeM) - Melaka, Malaysia, on 31 March 2016. The theme chosen for this event is ‘IDEA. INSPIRE. INNOVATE’. It was gratifying to all of us when the response for MERD’16 is overwhelming as the technical committees received more than 200 submissions from various areas of mechanical engineering. After a peer-review process, the editors have accepted 105 papers for the e-proceeding that cover 7 main themes. This open access e-Proceeding can be viewed or downloaded at www3.utem.edu.my/care/proceedings. We hope that these proceeding will serve as a valuable reference for researchers. With the large number of submissions from the researchers in other faculties, the event has achieved its main objective which is to bring together educators, researchers and practitioners to share their findings and perhaps sustaining the research culture in the university. The topics of MERD’16 are based on a combination of fundamental researches, advanced research methodologies and application technologies. As the editor-in-chief, we would like to express our gratitude to the editorial board and fellow review members for their tireless effort in compiling and reviewing the selected papers for this proceeding. We would also like to extend our great appreciation to the members of the Publication Committee and Secretariat for their excellent cooperation in preparing the proceeding of MERD’16

Factories of the Future

Engineering; Industrial engineering; Production engineerin

Experimental Investigations on Machining of CFRP Composites: Study of Parametric Influence and Machining Performance Optimization

Carbon Fiber Reinforced Polymer (CFRP) composites are characterized by their excellent mechanical properties (high specific strength and stiffness, light weight, high damping capacity etc.) as compared to conventional metals, which results in their increased utilization especially for aircraft and aerospace applications, automotive, defense as well as sporting industries. With increasing applications of CFRP composites, determining economical techniques of production is very important. However, as compared to conventional metals, machining behavior of composites is somewhat different. This is mainly because these materials behave extremely abrasive during machining operations. Machining of CFRP appears difficult due to their material discontinuity, inhomogeneity and anisotropic nature. Moreover, the machining behavior of composites largely depends on the fiber form, the fiber content, fiber orientations of composites and the variability of matrix material. Difficulties are faced during machining of composites due to occurrence of various modes of damages like fiber breakage, matrix cracking, fiber–matrix debonding and delamination. Hence, adequate knowledge and in-depth understanding of the process behavior is indeed necessary to identify the most favorable machining environment in view of various requirements of process performance yields. In this context, present work attempts to investigate aspects of machining performance optimization during machining (turning and drilling) of CFRP composites. In case of turning experiments, the following parameters viz. cutting force, Material Removal Rate (MRR), roughness average (Ra) and maximum tool-tip temperature generated during machining have been considered as process output responses. In case of drilling, the following process performance features viz. load (thrust), torque, roughness average (of the drilled hole) and delamination factor (entry and exit both) have been considered. Attempt has been made to determine the optimal machining parameters setting that can simultaneously satisfy aforesaid response features up to the desired extent. Using Fuzzy Inference System (FIS), multiple response features have been aggregated to obtain an equivalent single performance index called Multi-Performance Characteristic Index (MPCI). A nonlinear regression model has been established in which MPCI has been represented as a function of the machining parameters under consideration. The aforesaid regression model has been considered as the fitness function, and finally optimized by evolutionary algorithms like Harmony Search (HS), Teaching-Learning Based Optimization (TLBO), and Imperialist Competitive Algorithm (ICA) etc. However, the limitation of these algorithms is that they assume a continuous search within parametric domain. These algorithms can give global optima; but the predicted optimal setting may not be possible to adjust in the machine/setup. Since, in most of the machines/setups, provision is given only to adjust factors (process input parameters) at some discrete levels. On the contrary, Taguchi method is based on discrete search philosophy in which predicted optimal setting can easily be achieved in reality.However, Taguchi method fails to solve multi-response optimization problems. Another important aspect that comes into picture while dealing with multi-response optimization problems is the existence of response correlation. Existing Taguchi based integrated optimization approaches (grey-Taguchi, utility-Taguchi, desirability function based Taguchi, TOPSIS, MOORA etc.) may provide erroneous outcome unless response correlation is eliminated. To get rid of that, the present work proposes a PCA-FuzzyTaguchi integrated optimization approach for correlated multi-response optimization in the context of machining CFRP composites. Application potential of aforementioned approach has been compared over various evolutionary algorithms

12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons"

Epoxy resins show a combination of thermal stability, good mechanical performance, and durability, which make these materials suitable for many applications in the Aerospace industry. Different types of curing agents can be utilized for curing epoxy systems. The use of aliphatic amines as curing agent is preferable over the toxic aromatic ones, though their incorporation increases the flammability of the resin. Recently, we have developed different hybrid strategies, where the sol-gel technique has been exploited in combination with two DOPO-based flame retardants and other synergists or the use of humic acid and ammonium polyphosphate to achieve non-dripping V-0 classification in UL 94 vertical flame spread tests, with low phosphorous loadings (e.g., 1-2 wt%). These strategies improved the flame retardancy of the epoxy matrix, without any detrimental impact on the mechanical and thermal properties of the composites. Finally, the formation of a hybrid silica-epoxy network accounted for the establishment of tailored interphases, due to a better dispersion of more polar additives in the hydrophobic resin