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A five-layered aluminum–copper metal functionally graded material was developed through powder metallurgy process. The sample comprises different weight percentages of copper and aluminum that vary from 0 wt% to 100 wt % along the thickness direction. Erosion wear was performed on air jet erosion testing apparatus at a constant impact angle of 90o and impact velocity of 151 m/s. It was observed that erosion wear decreases when there is an increase in copper content. Layer 1 comprising 100 wt% of copper has shown 76.92% lower wear compared to layer 5 (100 wt% of aluminum). Besides, erosion resistance was enhanced at graded layers due to the formation of Al2Cu phase during sintering. Abrasive wear of metal functionally graded material was evaluated on the pin-on-disc test apparatus. Experiments were conducted at different loading conditions on various abrasive surfaces (P120, P800, and P2000). Irrespective of abrasive surface, the specific wear rate of aluminum–copper metal functionally graded material sample increased with an increase in load from 5N to 15N. At 5N, abrasive wear of metal functionally graded material on P2000 grit surface was 87.7% and 27.19% lower compared to P120 and P800, respectively. Eroded and worn-out surfaces were examined microscopically to understand the wear mechanisms and are discussed in detail.

This study mainly focuses on the wear and oxidation properties of highly cross linked UHMWPE (Ultra high molecular weight poly ethylene) replacing conventional UHMWPE as bearing material in Total Knee Arthroplasty (TKA) which were subjected to radiation under different sources and doses. Analysis of Vitamin E blended and Gamma radiated UHMWPE for TKA by simulation of artificial extended aging and daily heavy activities of a patient was done and observed no further degradation of the material due to wear and oxidation. It is noticed that improving wear resistance and anti-oxidation of the material depends on the radiation dose and post radiation treatment such as remelting used to remove free radicals in material. Mechanical property losses and wear losses during in vivo performance of a patient in longer period for two to three decades were also studied.

In this present study hybrid aluminium metal matrix composites (HAMMC) were prepared by employing stir casting technique at 725 °C. Reinforcements such as Alumina (Al2O3), Silicon carbide (SiC) and Boron carbide (B4C) of 44µ size were reinforced with base aluminium matrix Al-6061 T6 alloy. Wear test, Tensile test, Flexural test and Impact test were done on the hybrid aluminium metal matrix composites as per ASTM standards. It is observed that hybrid composite with 2 wt% each of SiC, Al2O3 and B4C has high tensile strength and wear strength. Composite with 6 wt% of B4C has second high tensile strength, hardness and impact strength when compared with rest of the hybrid composites because of its excellent mechanical properties. Porosity of the samples 1 and 2 is less than the value 2.3 which indicates greater uniformity of reinforcements in the matrix. Flexural strength and Hardness was studied and analysed. Morphological study of the hybrid composites was done using Scanning Electron Microscope (SEM) observed minimal cracks on the surface of the samples due to wear test.

The aim of this review is to study the effect of gamma radiation, particle size and molecular weight on the thermos mechanical and dynamic mechanical properties of the processed UHMWPE composites. Two studies were considered for analysing this report, one with MWCNT’s as reinforcement added to UHMWPE and processed through ball milling followed by gamma irradiation and the other study consists of analysing properties by comparing particle size and molecular weight of processed UHMWPE with purchased UHMWPE sample. From this study we observed radiated UHMWPE samples improves mechanical properties in larger extent and very less noticeable results from molecular weight and particle size have been observed between various grades of UHMWPE samples.

An automatic protection guard for bikes reduces the impact to the side panels, engine, and the rider's leg when the bike collides with the ground, which follows the reverse quick return mechanism. Include a tilt sensor to monitor the bike's lean angle to activate the system and a wave spring inside the hollow bars to absorb the impact. A tilt sensor will be installed and will set a lean angle to the system. When the bike crosses the calibrated lean angle, the system activates and releases the bars from the system installed onto the bike frame and will take the first contact with the ground surface. To match real-life situations, the time taken for the protection guards to move from initial position to extreme position has been calculated using solid Works motion analysis with an average time taken is 0.14 s, and to find the total deformation different loads and different spring constants have been applied using Ansys software the average deformation is 12 mm. The system helps the rider to ride the bike in a safe mode. The total design system is dynamic and varies with the bike segment but follows the same mechanism.

In this paper, we talk about the use of Auxetics in Sports Helmets, orientation, and the type of auxetic used. It also covers how the newly designed auxetic structures can sustain more impact energy when compared to the existing auxetic structures. This comparison gives us more clarity about the uses of auxetics in various other applications. Auxetics in simple terms are structures that have a negative Poisson's ratio. This is just a structural property and does not depend upon the material. Hence, it can be used in so many different applications such as defense applications, sports applications, impact absorption, drug dispensers when pores are open, test bay containment, etc. On moving forward, modifying a structure showed that there are improvements concerning Poisson's ratio as well as impact resistance. The challenge was then to make the foam such that it can absorb maximum impact energy. Based on this hypothesis, the proposed design was tested against an existing structure to postulate the difference in the impact energy. The Poisson’s ratio obtained was a staggering improvement from −0.73 to −1.27 which shows 75% decrease in Poisson’s ratio while boasting an increase in the overall energy of 330% from 50 J to 165 J.

In the ongoing world, everyone has been using the shock absorber as an essential component in most places like load carriers, large structures, and automobiles. This shock absorber plays a crucial role in the vehicle suspension to absorb the major shocks. So, if we absorb the shocks more efficiently, we can reduce the damage to the vehicle body, passenger and also, we can give a comfortable drive to the driver. In the suspension system, spring is the major part to absorb shocks through spring energy. So, if we use different springs or if we can modify the existing spring with better efficiency then we can increase the shock-absorbing capacity. Based on these ideas, I worked on the comparative analysis between coil spring shock absorber and wave spring shock absorber using stainless steel material under static structural and random vibrational analysis. Through these results, we can understand how effectively the wave spring shock absorber can replace the coil spring absorber in terms of load and deformation. In the end, we can find the effectiveness of springs under different random obstructions using the PSD concept in Ansys. This work can be helpful to mono shock absorber bikes and in other places where springs are required at low space areas. If we replace the coil spring with a wave spring with the same length, we can absorb more vibrations at a more comfortable level for the drivers.

In this paper, the study of analysis of spur gears and design principles maximum shear stress theory used for analytical calculation and in simulation analysis von mises theory is used in FUSION 360. The study static structural analysis of metal, non-metal polymer gears is mainly focused on the analysis of stress, strain, and pressure at the contact of teeth and factor of safety. Analyzing the stress, strain, pressure at the contact of teeth and factor of safety of metal and non-polymer-metal gears by using the material ductile cast iron and Nylon when both metal gears were in contact, both polymer gears were in contact and finally Metal and polymer gear in mesh with each other. Comparing the analytical results which were calculated from MSST (Tresca’s theory) and analyzing the all-mechanical properties of analytical results from von mises design theory which is used in Fusion 360 Simulation software. Comparing all the simulated results with different loading conditions when metal, polymer, and non-metal gears were in contact.

Natural fibres now a days replacing the conventional structural materials such as Aluminium, steel, wood etc. with their excellent weight to strength ratio and with their high mechanical properties. In this present investigation hybrid composites were fabricated using Hand layup process using the natural fibres such as Banana, Coconut, Jute and Cotton fibres reinforced with Polyethylene at different weight proportions of 5, 8, 10, 12, 15, 18, 20 wt%. Tests such as water absorption, flexural rigidity, tensile, hardness and few other mechanical tests were conducted on the hybrid natural fibre reinforced composites. Among the hybrid composites the coconut fibre with 20 wt% and banana fibre with 18% shows high tensile strength with 56.4 N/mm2 and 54 N/mm2 and flexural strength. Water absorption is less in the hybrid composite with coconut and cotton fibres as reinforcements and gains mass of 5gm and 7gm.

The mechanical performance of honeycomb sandwich structures fabricated with thermoplastic elastomer nylon core and 0D/2D hybrid polymer nanocomposite skin was investigated. The cell sizes were varied from 10 to 36 mm, and mechanical performance was evaluated along out-plane and in-plane orientations. Different tests like sandwich compression, bare core flexural, beam deflection and drop over impact test were carried out. The energy absorption ability of sandwich panels was evaluated by compression and drop weight impact test, and it was effectuated by cell size variation. A close agreement between the test results of the drop weight impact tester and FEM simulation was noted. The analysis of test results confirms that nylon honeycomb core with the variation of cell size possesses both compliance and stiffness besides good energy absorption abilities. The possible area of application includes backing layer in the body armor that can provide protection against blunt trauma and scar.

In India, the Firework industries are mostly located in and around Sivakasi, Tamil Nadu. Right from the initial phase of manufacturing till the transportation and storage of fireworks in the stores, risk to life and property is high so these industries are known to be highly hazardous industry. Fire is one of the major hazards which occur due to natural or man-made causes. The hazards in firework industry has been identified by walk around audit and the risk is quantified by Hazard Identification and Risk Assessment (HIRA) method for every task. After quantifying the risk suitable control measures are suggested to reduce the high-level risk into as low as possible. The risk zones as identified through the task-based quantification, helps the safety engineers to make necessary measures for the health and safety of the workers.

Honeycomb structures are extensively used energy-absorbing structures in the airplane, spacecraft and automobile body parts. The critical parameters that influence the aggregate energy absorption are cell size, wall thickness and node length. However, wall thickness is a crucial determining factor for crushing and buckling. The type of failure manifested to the crushing of the cells can be predicted with unit cell buckling. The current work investigated on quasistatic crushing properties of honeycomb structure by varying unit cell wall thickness and at constant cell size of 10 mm. The out of plane quasistatic compression test of nylon honeycomb core of various wall thicknesses i.e 1, 1.1, 1.2, 1.3, 1.4 and 1.5 mm is carried out using ANSYS 14 simulation. The results obtained from the test are in close agreement with unit cell buckling analysis for predicting the mode of failure. The ultimate compressive strength of 1.5 mm cell is observed to be 1.4 folds higher than that of 1 mm cell. The energy absorption obtained from load-displacement graph during compression test indicates the proportional relationship between wall thickness and energy absorption. High energy absorption ability for 1.5 mm wall thickness core infers superior crushing strength enables to use as energy-absorbing devices, where lightweight and strength are the prime concern.

The current work reports on the evaluation of mechanical properties of HDPE reinforced with multidimensional carbon based nanofillers: Nanodiamonds (ND)-0D, Multiwalled Carbon Nanotubes (CNT)-1D and Graphite nano Platelets (GNP)-2D. A twin screw injection molding machine was used to fabricate samples and designated according weight percentage of nanofiller in pure HDPE as 0.1 ND, 0.1 CNT,and 0.1 GNP respectively. The optimum mechanical properties was exhibited by 0.1 ND, with a noted increase of 33.6, 23, 42, 34% in hardness, Young‘s modulus, fracture stress and yield stress as compared with pure HDPE. Halpin Tsai equation was used to predict Young‘s modulus of composite and results confirmed a close agreement between predicted and experimental observations.

Lower limb amputation causes many changes and associated adjustments, which not only relates the damaged limb but also to the entire body. Today, the development of prosthetic devices for transfemoral amputation witness continual growth in medical applications. In India, an estimated 2.68 crore people have movement disability according to disability census 2011. At present 230,000 transfemoral amputees are in need of prosthetic devices to be facilitated for the better living style and standards, but low cost devices are yet to touch the market. And also, the amputee must endure to function in society uncomplaining that his disability may utterly inhibit or even prohibit the performance of various activities to which he has long been habituated. When compared to other disabilities, above knee amputation deprive a human to perform his activities and earn livelihood becomes an arduous task. Regardless of the developments in technology, above-knee amputees still indicates significant deficiencies in walking patterns, speed in walking. In this paper, a novel modelling of a pneumatic controlled bio mimetic articulated passive prosthetic spring loaded knee system for early and late swing and stance control has been presented. This work establishes a functional knee model developed by Catia software for various activities. The proposed model contemplates user needs and provides a low cost alternative with high stability and more durability to enable flexion-extension of prosthetic leg during the gait cycle.

Nano-material reinforced ultra high molecular weight polyethylene (UHMWPE) composites are generally used as a joint replacement material. An investigation has been done on Hardness and 3-point bending of ultra high molecular weight polyethylene (UHMWPE) which was loaded with Nano-diamond (ND) and Graphene (Gr). In order to perform some mechanical tests a UTM test equipment and hardness test equipment were utilized. Due to the formation of a good molecular bonding, there is a significant increase in hardness from 51 HV for neat UHMWPE to 57 HV at 0.5 wt% ND loading of ND/UHMWPE nanocomposites and 54 HV at 0.3 wt% Gr loading of Gr/UHMWPE nanocomposites. At 0.5 wt% of Gr loading, the highest value of the flexural modulus (3750 N/mm2) is observed. When 0.5 wt% of Gr and 0.3 wt% of ND is added, then there is a significant increase in ultimate flexural strength and flexural modulus by loading of nano fillers. In this study the fabrication of ND/UHMWPE and Gr/UHMWPE nanocomposites exhibited good mechanical properties and they can be explode for total joint replacement.

The advent of polymer nanocomposites and hybrid polymer nanocomposites had widened the scope of neat polymers by enhancing their mechanical and other properties. It had further extended its areas of applications from engineering to biomedical and other application of prominence. The current discussion is primarily focused on different application area of nanofillers and their role in improvising the mechanical properties of neat polymer. A systematic study of available literatures presents that the synergy between polymer matrix fillers and its dispersion in matrix material resulted in improvised mechanical properties. A critical review of different application area and preparation technique is also presented.

Globally around 300 million tonnes of plastic are produced, of which, less than 10% is recycled. Implementing recycled plastics in manufacturing i.e., by reusing them helps in the reduction of waste plastic scrap eventually. In this paper, an experimental study on recycled Polypropylene (RPP) and recycled High-Density Polyethylene (RHDPE) is carried out. The mechanical properties of the materials such as tensile strength, hardness, Young’s modulus, Impact strength, heat deflection temperature are evaluated using ASTM standards and further, the results are compared with the virgin Polypropylene & High-Density Polyethylene. Dynamic mechanical analysis is also performed on the samples to study the storage modulus, loss modulus, and tan delta values. In the investigations performed, it is observed that the Recycled materials have a lesser tensile strength, impact resistance, hardness when compared to the virgin materials. However, RHDPE has shown fairly good results when compared to RPP in impact resistance and tensile strength hence can be used in construction, military, and industrial applications. On the other hand, RPP has shown good results in terms of Hardness and Young’s Modulus, hence can be utilized in aircraft, automotive and engineering applications.

Fiber-reinforced composites are mainly used in aerospace engineering automobile and structural applications. The present study focuses on structural applications. The elastic response of material deals with shape recovery effect of material whereas viscous response plays a vital role in dispersing mechanical energy. Dynamic Mechanical Properties of fiber-reinforced epoxy composites (carbon, Kevlar, hybrid and sandwich configurations) were assessed in the current study. Fiber composites were manufactured with a weight ratio of 60:40 with a hardener ratio of 10:1 using a hand layup technique. Dynamic mechanical response of composite samples was assessed against temperature and frequency sweep. It has been observed that the carbon-reinforced epoxy shows the least tan delta value i.e. 0.22 at a temperature of 111.06 as compared to other composites, indicating its superior elastic behavior; while Kevlar has shown better damping properties. The sandwich configuration (carbon-Kevlar-carbon) exhibited visco-elastic properties indicating its utility with tougher skin and its core with higher damping ability. The Tan Delta of sandwich configuration is 50% higher than that of carbon fiber composite and 15% lower than that of Hybrid fiber composite. This enables the sandwich configuration capable of taking loads on its skin, and more energy dissipation at its core.

Nafion is a polymer which is of synthetic type with ionic properties. It is a sub-classification of Artificial Muscle Materials (AMM) and Electro Active Polymers (EAPs). These AMMs play a vital role in the advancement of material sciences. From the past few years, a lot of research is being carried out on Nafion to extract its unique qualities. This work investigates on glass transition temperature (Tg), tan delta and elastic modulus (E) of Teflon Fabric Reinforced Nafion (TFRN) membrane using Universal Tensile testing and Dynamic Mechanical Analysis (DMA). When results are validated with existing data of Nafion 117 (N-117), E is observed as 206.03 MPa (2.93% greater than N-117) from tensile testing, which is performed at 58% Relative Humidity (RH) and 32 °C ambient temperature. This connotes, TFRN has better strength when compared to N-117. Regarding Tg, N-117 exhibited 26.06% more than the TFRN membrane. Though the storage modulus (E′) of the TFRN membrane is less, its loss modulus (E″) has shown that N-117 has more heat dissipation.

This review is focused on the rapidly expanding field of porous materials for the sensor, actuator, energy storage and energy generation application. The synthesis methods to produce excellent poro...

Sandwich structures with honeycomb core find specific application in impact resistance and energy absorption applications. However, such studies were limited to cores with metallic honeycomb, which had limited energy absorption abilities apart from extrinsic weight. The current work aims to fabricate hybrid sandwich beams made with PCTPE (Plasticized Co-polyamide Thermoplastic Elastomer) nylon using Fused Filament Fabrication (FFF). The cell size was varied from 10 to36 mm with a variation of longest diagonal. The face sheets were prepared with High-density polyethylene (HDPE) matrix with equal loading of Graphite nanoplatelet and Nano-diamond hybrid filler system. The face sheets were joined to honeycomb core to prepare sandwich panel with tailored made adhesive. It was observed that during out of the plane test, for 10 mm cell the SEA (specific energy absorption) was 1.15 kJ/kg, which decreased upto and 69% for 36 mm respectively. During the in-plane flexural test, the minimum flexural modulus showed by 36 mm longest diagonal cell was 31 MPa, which had increased further by 24, 50, 62, 67 and 76% for 27, 21, 15, 12 and 10 mm respectively, indicating elastic nature and damping ability of sandwich beam. The free vibration analysis was performed on by taking cantilever configuration. The experimentally obtained results were then validated using Ansys-14 simulation. It was concluded that PCTPE nylon core exhibited dual properties of stiffness and compliance for the period of out-plane testing and in-plane respectively, with a threshold limit of 36 mm cell size.

A thrust on improvement of different properties of polymer has taken a contemporary route with advent of nanofillers. Although several nanofillers are existent; MultiWalled Carbon Nanotubes- (MWCNTs) and h-Boron Nitride nanoplatelets-(h-BNNPs) unique combination of 1D and 2D dimensional geometry aids an advantage of B-C-N triad elemental effects on properties of tested samples. The current study aims to investigate the effects of MWCNT and h-BNNP reinforcement in High Density Polyethylene (HDPE) for high load bearing areas of medical applications requiring both elastic and viscous behavior. The results were analyzed keeping a view of its application in areas like HDPE based fracture fixation plates, acetabular cups and others. The composite and hybrid samples with different loadings were prepared after surface modification of nanofillers by mechanical mixing and molding technique. The dynamic nano-mechanical properties like storage modulus, loss modulus and tan delta were assessed for each sample during frequency swept from 10 to 220 Hz. The viscoelastic properties like hc/hm, H/E, elastic-plastic deformation were investigated and evaluated. At a frequency of 10 Hz, the storage and loss modulus of 0.1 CNT increased by 37.56% and decreased by 23.52% respectively on comparison with pure HDPE. This infers a good elastic as well as viscous behavior. Overall elastic behavior of 0.1 CNT was confirmed from tan delta evaluation. The interaction between B-C-N elemental triad had significant effect on creep strength, visco-damping property (hc/hm and H/E), elastic plastic displacement and pile-up and sink-in behavior. Highest creep strength and visco-damping property was exhibited by 0.25 CNT/0.15 BNNP hybrid. The elastic-plastic displacement of hybrid composite was noted as least, which decreased by 30% on comparison with pure HDPE. It can be inferred that presence of 1D-MWCNT and 2D-h-BNNP had significant effect on important dynamic viscoelastic and creep properties of HDPE based hybrid composites.

Engineering polymers poses critical loopholes like lack of stiffness, hardness and wear resistance which were influenced by nanomechanical properties like hardness, plasticity index and differential damping behaviour. Study reports on preparation and characterization of novel nanocomposite and hybrid nanocomposite that would be alternate to virgin engineering polymers using quasistatic and dynamic nanoindentation. Nanocomposites and hybrid nanocomposites were prepared using High density polyethylene (HDPE) as matrix reinforced with alternate and possible combination of 0D (Nano-Diamonds-(NDs), 1D (Multi-Walled Carbon Nanotubes- (MWCNTs) and 2D (Graphite nanoplatelets-(GNPs) nanofillers using twin screw injection moulding machine. Quasi static Properties like; hardness, Young's modulus of HDPE/0.1 GNP/0.1 ND was observed to increase by 83.33, 25.17% on comparison to pure HDPE and plasticity index reduced by 67.77%. Dynamic properties like; storage modulus, loss modulus and Tan delta at a frequency sweep from 10 to 220 Hz confirm the overall elastic behavior of the nanocomposites.

A series of novel low band gap donor-acceptor (D-A) type organic co-polymers (BT-F-TPA, BT-CZ-TPA and BT-SI-TPA) consisting of electron-deficient acceptor blocks both in main chains (M1) and at the pendant (M2) were polymerized with different electron rich donor (M3−M5) blocks, i.e., 9,9-dihexyl-9H-fluorene, N-alkyl-2,7-carbazole, and 2,6-dithinosilole, respectively, via Suzuki method. These polymers exhibited relatively low band gaps (1.65−1.88 eV) and broad absorption ranges (680−740 nm). Bulk heterojunction (BHJ) solar cells incorporating these polymers as electron donors, blended with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) or [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as electron-acceptors in different weight ratios were fabricated and tested under 100 mW/cm2 of AM 1.5 with white-light illumination. The photovoltaic device containing donor BT-SI-TPA and acceptor PC71BM in 1:2 weight ratio showed the best power conversion efficiency (PCE) value of 1.88%, with open circuit voltage (V oc) = 0.75 V, short circuit current density (J sc) = 7.60 mA/cm2, and fill factor (FF) = 33.0%.

Hybrid nanocomposites are a class of materials with exceptional properties due to the synergizing effect of individual fillers. Current work reports the tribological behaviour of high densitypolyethylene-(HDPE) reinforced with 1D-(Multi walled carbon nanotubes-(MWCNTs) and 2D-(h-Boron Nitride nanoplatelets-(BNNP) nanofillers. MWCNTs and BNNPs are chemically modified prior to solution deposition on HDPE and then processed through injection moulding. Testing was performed by varying Load, Speed and Sliding distance for all samples. Parameters such as wear volume, static and kinetic friction co-efficient, surface roughness in steady state and run-in phases, hardness, plasticity index and thermal expansion coefficient were reported. The wear volume of 0.1BNNP composite has shown reduced values as compared to 0.1MWCNTfor all parameters of testing. Highest wear resistance is exhibited by HDPE/0.25MWCNT/0.15BNNP hybrid nanocomposite. Plasticity index was reduced by 40% for HDPE/0.25MWCNT/0.15BNNP sample. The surface roughness increased with speed and sliding distance, while reduced with increasing load. Static and kinetic friction coefficients were also estimated. The surface morphology was examined at the end of Run-in and Steady state to identify prominent wear mechanisms. It is concluded that BNNP based composites possess better properties compared to MWCNT for equal loading, however, Hybrid composites of 1D/2D nanofillers has been shown superior properties.

High Density Polyethylene (HDPE) exhibits good mechanical properties but poor resistance to wear which impedes its application in low load bearing industrial components. The current work is focused to understand the influence of contact pressure on the tribological performance of multidimensional carbon based filled HDPE hybrid nanocomposite. The novelty of the work lies in an in-depth investigation of the contact pressure which is observed to influence the wear performance of HDPE based composites and hybrids. The nanofillers of different dimensions; Nano-diamond (ND)-0D, Multiwalled Carbon Nanotubes (MWCNT)-1D and Graphite Nanoplatelets (GNP)-2D were chosen as reinforcements. The individual role of nanofillers and its response to the contact pressure and the prominent wear mechanisms exhibited thereof were studied in detail. 0.1 GNP/ND was noted to exhibit least contact pressure with highest wear resistance and the dictum was exonerated with Tanδ~0.5 confirming its damping abilities thereby pronouncing more wear resistance. The presence of ND in HDPE had strongly influenced the wear performance and it was analyzed based on electron affinity hypothesis. It was concluded that correlating contact pressure with wear volume, and related wear mechanisms of polymeric materials would be a novel contribution in the relevant field.

Nanotechnology has extended applications of conventional engineering plastics like high-density polyethylene (HDPE) to different biomedical implants such as articular cartilage and fracture fixation plates. However, applications in a load-bearing element like a prosthetic knee require estimation of static, dynamic mechanical, and variation of mechanical properties with temperature. The current work reports on the application of HDPE-based nanocomposite as a possible substitute for a metallic knee in a prosthetic leg. HDPE was reinforced with multiwalled carbon nanotubes (MWCNTs)-1D and boron nitride nanoplatelets (h-BNNPs)-2D to form different composites and hybrids. The preparation route followed the mechanical mixing tandem by curing in a vacuum oven. Dynamic mechanical thermal analysis (DMTA) results confirmed the best elastic and damping property by 0.1 MWCNT composite. The mechanical properties like hardness, impact toughness, and stiffness of 0.25 MWCNT/0.15 h-BNNP were observed to increase by 172 %, 190 %, and 50 % in comparison with pure HDPE. A similar observation was noted during the evaluation of thermal conductivity, thermal stability, and %crystallinity. A modified Halpin–Tsai and Hamilton–Crosser model was used to predict the stiffness and thermal conductivity of composites. The test results confirmed 0.25 MWCNT/0.15 h-BNNP as a potential possible substitute for a metallic knee in a transfemoral prosthesis.

Ultra high molecular weight polyethylene (UHMWPE) remains a primary choice of material for load bearing applications in total joint arthroplasty. Superior mechanical properties and wear resistance are unique to its performance. However, the addition of nanomaterials has improved its properties significantly. In the present study, a novel sandwich configuration has been considered to achieve unique surface and bulk properties specific to these sandwich composites. UHMWPE was reinforced at various loadings of 0.1, 0.3, 0.5, and 0.7 wt. % by surface modified Nano-diamond (ND). It is observed that the young's modulus, yield stress, fracture stress and toughness of UHMWPE were improved by 15, 31, 30, and 49.6% respectively at the optimum loading of 0.5 wt. % ND filler. The % of elongations and impact strength showed best results at 0.3 wt. % ND. Sandwich nanocomposites were prepared with the optimum loading of 0.3 & 0.5 wt. % ND and assessed for their properties and behaviour. The sectional hardness of sandwich nanocomposites revealed the cross-sectional variation of properties of the material. The reasons for diminution of the mechanical properties of nanocomposites and sandwich nanocomposites were also ascertained by rheological studies. The vibration response, damping behaviour, water contact angle and density of the composites which influence the longevity of the implant material were also assessed. The sandwich composite (PE 0.3ND - PE - PE 0.3ND) has shown better performance in all respect as compare to SW1 and SW3 composite due to good intermingling between the adjacent layers. It is concluded that the existence of ND improved the surface properties and mechanical properties of UHMWPE. However, sandwich nanocomposites have shown better properties unique unto itself.

Ultra-high molecular weight polyethylene (UHMWPE) has been used as a surface for acetabular in total joint replacements for the past 60 years. However, the performance of the implant is influenced by the increase in temperature because of the articulating motion and the contact asperities, which affects its longevity. The viscoelastic properties of multi-walled carbon nanotubes (MWCNTs) reinforced UHMWPE nanocomposites with respect to temperature and irradiation dose are not reported so far. Hence, an attempt was made to study the viscoelastic properties of UHMWPE by varying concentration of MWCNTs and intensity of irradiation dose. The test samples were subjected to sinusoidal loading in the temperature range of 30–80°C. Ultra-high molecular weight polyethylene nanocomposites were prepared at different concentrations of MWCNTs such as 0.5, 1.0, 1.5 and 2 wt-% using compression moulding process and the nanocomposites were subjected to 60Co gamma irradiation up to 100 kGy dose. The viscoelastic characteris...

A series of well-defined donor–acceptor (D–A) conjugated oligomers incorporating thieno[3,4-c]pyrrole-4,6-dione (TPD) acceptor and two symmetrical thiophene units as donor π-bridge along the axes of triphenyl amine core have been synthesized and explored in bulk heterojunction (BHJ) solar cells. Under illumination with AM 1.5 white light (100 mW/cm2), the performance of BHJ photovoltaic devices with an active layer of an electron-donor oligomeric material (TPATP1, TPATP2 or TPATP3) blended with an electron acceptor {[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) or [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) at various weight ratios has been investigated. The photovoltaic device containing the donor TPATP1 and the acceptor PC71BM at a 1:3 weight ratio exhibited the best efficiency of 1.87% with an open circuit voltage (Voc) of 0.86 V, short circuit current (Jsc) of 6.59 mA/cm2, and a fill factor (FF) of 33%. These results demonstrate that irrespective of conjugation length, tuning of materials with efficient donor and acceptor materials can enhance the optical, electrochemical and eventually the power conversion efficiency (PCE) values of BHJ solar cells. Furthermore oligomers containing TPD acceptor in different structural form have different unique contribution towards photovoltaic properties.

Carbon matrix composites (CMCs) are generally used in aerospace industry for missile nose tips, re-entry heat shields, rocket motor nozzles, and brakes for aircrafts because of its attractive properties like light weight, low density, high strength, stiffness, high thermal conductivity, low coefficient of thermal expansion, high fracture toughness, good fatigue, creep resistance, and excellent thermal shock resistance. The unique property of this material is that its strength increases with increase in temperature. But there are some problems associated with this material like oxidation at moderately elevated temperatures and high manufacturing cost. Therefore, this chapter presents a critical review of carbon matrix composites. The attention is focused on manufacturing of carbon fiber, different techniques of making carbon–carbon matrix materials, microstructural examination of CMCs, mechanical properties of CMCs, oxidation protection and applications of CMCs.

The development of cement and cement based, concrete and concrete based composites for industrial applications are reported in this chapter. It has focused on the types of cements which includes Portland, white, blended, supersulfated, high alumina cements; mechanism of hydration of cement and different properties of the cement like strength, permeability, porosity, elastic modulus shrinkage, and creep. This chapter also dealt with manufacturing process and properties of concrete like strength, Poisson’s ratio, coefficient of expansion, creep, shrinkage, durability, and corrosion. This chapter has also given insight on manufacturing and properties of short/long fiber reinforced cement and concrete composites which includes bond strength, toughness in uniaxial tension, fracture mechanism, and principles of fiber reinforcement. It has also dealt with manufacturing, durability, and applications glass and fiber reinforced cement, wood, and vegetable fiber reinforced cement, poly vinyl alcohol (PVA) fiber reinforced cement. This chapter has also focused on manufacturing, durability, and applications of PVA reinforced concrete and steel fiber reinforced concrete.

Ultra high molecular weight polyethylene (UHMWPE) was reinforced by chemically treated multi walled carbon nanotubes (MWCNTs) up to 2.0 wt% and later subjected to gamma irradiation up to 100 kGy dose. The influence of MWCNTs on the hardness and wear resistance of UHMWPE was evaluated before and after the irradiation process. The hardness of UHMWPE was increased by 89% by homogeneous dispersion of 2 wt% MWCNTs and 100 kGy irradiation. Wear studies on the test samples revealed that the wear volume of unirradiated UHMWPE was reduced by 31%, 54% and 73% upon dispersing 2 wt% MWCNTs, 100 kGy irradiation and the combination of both, respectively. The surface morphology and topography of the wear tracks were examined to understand the wear mechanisms of UHMWPE and its composites. Though the wear mechanism observed in the polymer and composites under normal and irradiated condition is found to be the same, the severity of wear was found to be reduced for irradiated composites compared to unirradiated UHMWPE. The crosslink density (CLD) of composites was found to be higher than that of UHMWPE. It is concluded that the cumulative effect of the presence of MWCNTs and irradiation effectively increased the wear resistance of UHMWPE.

Materials for smart applications are finding their utility in wide variety of actuators. Shape-memory alloys are a class of materials that undergo deformation upon heating above a critical temperature. The crucial property of actuators is to possess negligible recoverable strain after millions of fatigue cycles. With the increasing applications of shape-memory alloys, the fatigue and crack propagation behavior, failure mechanisms, using phenomelogical curves are very crutial and hence the mechanisms are discussed in detail. Although, several metals exhibit shape-memory effect, Ni–Ti and Cu based alloys are widely used. The present chapter discusses fatigue properties and related theories, crack initiation, phase transformation and the dependent properties, superlasticity, mechanical properties such as stress–strain curves, phase deformation and work hardening of single crystal, polycrystalline shape-memory alloys are presented with evidence from literature on both theoritical and experimental models.