Prakash Gope - Academia.edu (original) (raw)

Papers by Prakash Gope

Experimental and Applied Mechanics, Volume 6, 2011

In the present investigation, fibers from banana stem and Bagasse are used in addition to low wt%... more In the present investigation, fibers from banana stem and Bagasse are used in addition to low wt% of silica to cast bio composites. Extraction of the banana fibers, Bagasse fibers and preparation of both banana and Bagasse fibers were carried out as explained elsewhere in literature. The lengths of the fibers are kept between 180 to 425 micrometer. Composites, containing

Abstract- Clouds provide an inexpensive remote access to hardware and storage resources. It has b... more Abstract- Clouds provide an inexpensive remote access to hardware and storage resources. It has become a widely used term in the industry. Academics has not remained unaware of this trend, and several educational solutions based on cloud technologies are already in place, especially for software as a service (SAAS) cloud. Extending this usage to infrastructure and platform clouds (IAAS,PAAS) has not been explored yet. There is no design to classify clouds based on different stages involved in the learning process of academics especially for computer science students. An implementation of platform service clouds is valued by both students and professors to achieve the course objectives and also these clouds offer a significant improvement over existing situations in labs where much effort was devoted to setting up the software necessary for course activities. These conventions strongly applies to other similar disciplines where students interact with resources that are not-self-conta...

Frattura ed Integrità Strutturale

In the present work finite element method has been employed to study the interaction of multiple ... more In the present work finite element method has been employed to study the interaction of multiple cracks in a finite rectangular plate of unit thickness with cracks on the same side under uniaxial loading conditions. The variation of the stress intensity factor and stress distribution around the crack tip with crack offset distance has been studied. Due to the presence of a neighbouring crack, two types of interactions viz. intensification and shielding effect have been observed. The interaction between the cracks is seen to be dependent on the crack offset distance. It is seen that the presence of a neighbouring crack results in the appearance of mode II stress intensity factor which was otherwise absent for a single edge crack. It can be said that the proximity of cracks is non-desirable for structural integrity. The von-Mises stress for different crack orientations has been computed. Linear elastic analysis of state of stress around the crack tip has also been done.

Asian Journal of Engineering and Technology, 2015

Composite materials are made from two or more constituent materials with significantly different ... more Composite materials are made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct on a macroscopic level within the finished structure. In the present work a silica-styrene-butadiene rubber hybrid composite material is developed with 1 and 2 wt% of nano sized silica particle and 0.25 to 1.5 wt% of styrene-butadiene rubber mixed in resin. About 75% of wear reduction is found due to addition of silica particle, whereas addition of styrene-butadiene rubber has insignificant effect on the wear rate. However, it slightly increases the wear rate as compared to silica filled epoxy composite. Hybrid composites with higher silica content exhibit higher hardness. A good liner correlation between wear rate and hardness exists with probability p 0.8.

Appl. Soft Comput., 2015

Summary of predicted and experimental results. The crack growth under multiple cracks is highly i... more Summary of predicted and experimental results. The crack growth under multiple cracks is highly influenced by neighbouring cracks.No mathematical relation is available to predict the crack initiation direction.ANN has been used to predict crack growth direction in multiple crack geometry.The effect of degree of input variables and hybrid combination of activation functions is studied.Nonlinear and linear activation functions are used through the one and two-hidden layer ANN.The experimental dataset as first or second degree were used.Higher order input variables are found to be more suitable. The objective of this study is to design an efficient artificial neural network (ANN) architecture in order to predict the crack growth direction in multiple crack geometry. Nonlinear logistic (sigmoid and tangent hyperbolic) and linear activation functions have been used through the one- and two-hidden layer ANN. 85 tests were conducted on aluminium alloys under different crack positions, defi...

Journal of the Mechanical Behavior of Materials, 2020

Present work studies the effect of particle reinforcement on fracture toughness of bio-composites... more Present work studies the effect of particle reinforcement on fracture toughness of bio-composites. The filler used has been taken as rice husk. Epoxy resin has been taken as matrix material. Composites with varying filler loading of 10, 20, 30 and 40 wt.% were fabricated. The fracture toughness was seen to be increasing with increase in filler loading. However beyond 20% there was a decrease in fracture toughness with increase in filler loading. The effect of fibre treatment on toughness was also observed. Rice husk fibres pre-treated with NaOH were used. It was observed that fracture toughness further improved due to treatment. The increase in fracture toughness was significant. Fracture toughness increased from 1.072 to 2.7465 MPa√mm for 20% reinforcement and after treatment it increased to 2.876 MPa√mm. It was observed that concentration of treatment media also affects the fracture toughness. Further the effect of hybridization was observed by addition of rice husk ash as a secon...

In the present investigation temperature dependence fatigue strength behaviour of Inconel 825 sup... more In the present investigation temperature dependence fatigue strength behaviour of Inconel 825 super alloys is investigated. Based on the experimental results different S-N models have been derived and suitable model for the prediction of fatigue strength have been proposed. An inverse power and exponential relation between fatigue strength and absolute temperature is demonstrated. The proposed models are used to predict the fatigue life using well known Palmgren-Miner rule. Based on high to low and low to high load steps test data sets under identical test conditions, Miner rule based statistical damage constant is stochastically modeled for fatigue life prediction at different level of probability and validated. The modeling process combines a probabilistic fatigue damage accumulation and a stress-life-temperature relation technique.

Open Health

COVID-19 viruses are primarily transmitted between people via respiratory droplets generated from... more COVID-19 viruses are primarily transmitted between people via respiratory droplets generated from an infected person while coughing, sneezing, exhaling or close contact. Hence, the use of masks are part of prevention and control measures to limit the spread of COVID-19. A comprehensive study on various materials used in masks is required. The filtration efficiency of cotton masks increases with increase in thread count and number of layers, but breathability is affected and therefore a risk for longer durations. Cotton-based masks have filtration efficiency ranging from 5% to 80% depending on the number of layers. Combinations of different hybrid fabric materials and design have an efficiency ranging from 37% to 97%. Bio-cellulose, which is derived from cellulosic biomass by synthesis techniques involving various physical and chemical processes followed by refining techniques, possesses remarkable properties including biodegradability, biocompatibility, low toxicity, etc., making it...

Veterinary Surgery

OBJECTIVE Quantitation of mechanical properties of a novel locking compression plate (LCP) for bo... more OBJECTIVE Quantitation of mechanical properties of a novel locking compression plate (LCP) for bovine tibia. STUDY DESIGN Prospective in vitro study. SAMPLE POPULATION Adult Murrah buffalo (250-350 kg) tibiae. METHODS Forty tibiae were randomly assigned to five treatment groups (n = 8/group): intact bone and bone constructs with a standard nonlocking plate, single LCP, double LCP, and novel LCP. During implant application, a mid-diaphyseal, oblique osteotomy was performed in all constructs, which were subsequently tested in axial compression (n = 4 each) or three-point craniocaudal bending (n = 4 each). Novel LCP alone (n = 4) was tested only in bending. Stiffness, yield load, ultimate failure load, and bending moment were determined from the load deformation curves and compared among different treatment groups (P < .05). RESULTS Under compression, yield load of the novel LCP (24.07 ± 3.45 kN) was greater than that of the nonlocking plate (11.10 ± 2.46 kN) and the single LCP (18.01 ± 2.07 kN) but less than that of the double LCP (30.61 ± 1.95 kN), and ultimate failure load of the novel LCP (25.85 ± 4.32 kN) was greater than that of the nonlocking plate (13.18 ± 2.91 kN) but similar to that of the single LCP (21.17 ± 2.33 kN) and the double LCP (32.40 ± 1.46 kN). Bending moment, yield load, and ultimate failure load of the novel LCP were 565.37 ± 79.30 Nm, 7.90 ± 1.14 kN, 9.83 ± 1.38 kN, respectively, which were greater than those of the nonlocking plate and the single LCP but comparable to those of the double LCP. CONCLUSION The novel LCP developed for bovine tibia was mechanically superior to the standard nonlocking plate or the single LCP and comparable to the double LCP. CLINICAL SIGNIFICANCE The novel LCP may provide rigid fixation of tibial diaphyseal fractures in buffaloes and cattle weighing 250 to 350 kg.

Fatigue & Fracture of Engineering Materials & Structures

Journal of the Mechanical Behavior of Materials, Jun 9, 2018

Abstract Friction stir welding (FSW) is a solid-state joining which reduces the structural weight... more Abstract Friction stir welding (FSW) is a solid-state joining which reduces the structural weight significantly and hence it has received worldwide attention for the joining of aluminium alloys. In this paper, fatigue tests and finite element analysis were employed to study the mechanical and fatigue properties of a friction stir welded T-joint of 19501 aluminium alloy. An LS-2 FSW machine with 100 kN capacity was used to fabricate the T and butt joints. The tensile properties of the friction stir welded joint show that there is a marginal reduction of about 5% in strength and ductility as compared to an un-welded 19501 aluminium alloy. S-N test results of theT-joint specimen at two stress ratios of 0 and −1 showed that there was a reduction of 15% in the fatigue strength due to the change of stress ratio from 0 to −1. The effect of mean stress can be well approximated using Goodman’s criterion as compared to Gerber’s or Soderberg’s criteria. The predicted fatigue lives from the proposed model using the Palmgren-Miner rule (PMR) were found to be within reasonable accuracy. Micrographs shown for the fracture surfaces of the retreating side, mid-weld zone and the advancing side of the T-joint indicate that fracture surfaces are a mixture of dimple and cleavage features.

International Journal for Computational Methods in Engineering Science and Mechanics

ABSTRACT The fatigue crack growth model is expressed as a function of mechanical properties. The ... more ABSTRACT The fatigue crack growth model is expressed as a function of mechanical properties. The uncertainties associated with the crack growth process are incorporated assuming them as random variable following a statistical distribution. The effect of material nonhomogeneity is included in the model through a random process parameter of Gaussian type. Assuming fatigue life as a random variable, probability-confidence bounded mean crack growth relation is developed and an algorithm is presented. The model is validated through the experimental and predicted results from several data sets.

Journal of the Mechanical Behavior of Materials

Natural fibers from agricultural waste have received more attraction than traditional synthetic f... more Natural fibers from agricultural waste have received more attraction than traditional synthetic fibers in recent years. In present investigation epoxy/rice husk composite has been fabricated to utilize the agricultural waste which can be recycled easily and overcome the pollution problems due to smoke and fine silica ash. Study of interfacial bonding and dispersion of rice husk in epoxy resin has been studied through scanning electron microscope image. Characterization of fabricated composites has been done by mechanical properties. Ultimate tensile strength, Young’s Modulus and hardness are highest at 10 wt.% of rice husk particle and their values are 66.5 MPa, 616.46 MPa and 16.8 HV respectively. Machinability of epoxy/rice husk composites has been determined through drilling operation. Effect of feed rate (0.1, 0.2 and 0.3 mm/rev), speed (300, 600 and 900 rpm) and wt.% of reinforcement (10, 15 & 20) have been studied on machinability of epoxy/rice husk composites. Taguchi L27 ort...

Engineering Science and Technology, an International Journal

Abstract The statistical aspect of mode I, mode II and mixed mode I/II fracture toughness of epox... more Abstract The statistical aspect of mode I, mode II and mixed mode I/II fracture toughness of epoxy based bio-composite reinforced with 20 wt% walnut shell particle and 10 wt% coconut fiber is studied. The bio-composite is fabricated by the squeeze casting method. A series of fracture tests are conducted on hybrid bio-composite using three point bend, four point bend and semicircular arc bend specimen. The statistical distribution of normalized geometry parameters, T stress, crack tip plastic zone size, particle and fiber size are studied. Generalized maximum tangential stress criterion is modified considering the stochastic nature of the geometry and strength parameters assuming them to follow two parameters Weibull probability distribution. The model developed is applied to the bio-composite and predicted results are compared with the experimental values. Very good agreement is found between the experimental results and predicted results. The variability in the fracture toughness values are correlated with the particle and fiber size determined from scanning electron microscopy.

Frattura ed Integrità Strutturale

A finite rectangular plate of unit thickness with two inclined cracks (parallel and non parallel)... more A finite rectangular plate of unit thickness with two inclined cracks (parallel and non parallel) under biaxial mixed mode condition are modelled using finite element method. The finite element method is used for determination of stress intensity factors by ANYSIS software. Effects of crack inclination angle on stress intensity factors for two parallel and non parallel cracks are investigated. The significant effects of different crack inclination parameters on stress intensity factors are seen for lower and upper crack in two inclined crack. The present method is validated by comparing the results from available experimental data obtained by photo elastic method in same condition.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

In this study, the mechanical properties and fatigue life of 19501 aluminum alloy friction stir w... more In this study, the mechanical properties and fatigue life of 19501 aluminum alloy friction stir welded T-joint is investigated. Tensile properties of friction stir welded joint show that there is a marginal reduction of about 5% in strength and ductility as compared to unwelded 19501 aluminum alloy. Fatigue test results of T-joint specimen at two stress ratios of 0 and -1 show that there is a reduction of 15% in fatigue strength due to change of stress ratio from -1 to 0. Also, higher variation is seen in fatigue strength in low cycle zone than the high cycle zone. Effect of mean stress on fatigue life is discussed on the basis of different mean stress effect models. Morrow’s mean stress effect model is found to be better than other models. Micrographs from the fracture surfaces of retreating side, mid weld zone, and advancing side of the T-joint indicates that fracture surfaces are cleavage fracture. Different sizes of inter-metallic bonding are seen in the micrographs, which indic...

International Journal of Engineering Research and Applications

Engineering materials having two or more different physical or chemical properties make co mposit... more Engineering materials having two or more different physical or chemical properties make co mposites. In recent years natural fibres from agricultural waste have received more attraction as they offer number of advantages over traditional synthetic fibres. The proposed study has great use of agricultural waste which can be recycled easily and is environmental friendly also. A bio-co mposite reinforced with rice husk, rice husk particulate and mixtu re of husk and particulate i.e. hybrid in epo xy resin has been fabricated. The decrease in Ultimate Tensile Strength, Young's Modulus and % Elongation was observed with increase in wt. %. U ltimate Tensile Strength, Young's Modulus and % Elongation was recorded 66.5 MPa, 616.46 MPa and 10.6% respectively at 10%wt of rice husk particle reinforced co mposite.

Journal of Reinforced Plastics and Composites

The effect of bio-fibres and bio-particles on the fracture toughness has been investigated. Epoxy... more The effect of bio-fibres and bio-particles on the fracture toughness has been investigated. Epoxy resin is used as matrix material and different bio-fibers such as banana fiber, bagasse fiber, coconut fiber and particles such as silica and walnut shell particle with different wt% are added as reinforcing material. The mode I fracture toughness tests are conducted in a servo hydraulic universal testing machine. The results show that the fracture toughness of bio-composites reinforced with 20 wt% bagasse or 10 wt% coconut fiber are 1.108 MPa √ m and 1.094 MPa √ m, respectively which are about 8% and 7% higher than neat epoxy. Addition of 2 wt% of silica with 20 wt% of bagasse shows 60% increment of fracture toughness with respect to bagasse and 72% increment with respect to neat epoxy. Hybridisation of bagasse with banana fibers shows 54% decrease in fracture toughness as compared to bagasse and 13% increase as compared to banana. The overall fracture toughness of hybrid bio-composite...

Procedia Engineering, 2017

Abstract The increased application of aluminum alloy in the past decades in automotive industries... more Abstract The increased application of aluminum alloy in the past decades in automotive industries has suggested the researchers to study its behavior under different loading conditions and applications. Tungsten inert gas (TIG) welding in aluminum alloy is one of the widely used methods to manufacture the automobile parts. The strength of welded components may differ under different loading conditions. Moreover, if cracks develop in the welded components during their service period, it makes the working conditions worst. The working efficiency of same component may differ at different strain rates. The effect of strain rate on the fracture behavior of aluminum alloy containing cracks or notches is important to be studied to predict the failure of the component. The present work describes an experimental investigation to study the influence of high strain rates on the fracture behavior and tensile properties of welded 6061 aluminum alloy. The tensile tests have been performed on 100 kN Universal Testing Machine under uniaxial static loading. At higher strain rates, considerable increase in yield strength and ultimate tensile strength has been observed. This may be due to insufficient elastic recovery time at higher crosshead speed, and thus the yield as well as ultimate strength of the material increases.

Experimental and Applied Mechanics, Volume 6, 2011

In the present investigation, fibers from banana stem and Bagasse are used in addition to low wt%... more In the present investigation, fibers from banana stem and Bagasse are used in addition to low wt% of silica to cast bio composites. Extraction of the banana fibers, Bagasse fibers and preparation of both banana and Bagasse fibers were carried out as explained elsewhere in literature. The lengths of the fibers are kept between 180 to 425 micrometer. Composites, containing

Abstract- Clouds provide an inexpensive remote access to hardware and storage resources. It has b... more Abstract- Clouds provide an inexpensive remote access to hardware and storage resources. It has become a widely used term in the industry. Academics has not remained unaware of this trend, and several educational solutions based on cloud technologies are already in place, especially for software as a service (SAAS) cloud. Extending this usage to infrastructure and platform clouds (IAAS,PAAS) has not been explored yet. There is no design to classify clouds based on different stages involved in the learning process of academics especially for computer science students. An implementation of platform service clouds is valued by both students and professors to achieve the course objectives and also these clouds offer a significant improvement over existing situations in labs where much effort was devoted to setting up the software necessary for course activities. These conventions strongly applies to other similar disciplines where students interact with resources that are not-self-conta...

Frattura ed Integrità Strutturale

In the present work finite element method has been employed to study the interaction of multiple ... more In the present work finite element method has been employed to study the interaction of multiple cracks in a finite rectangular plate of unit thickness with cracks on the same side under uniaxial loading conditions. The variation of the stress intensity factor and stress distribution around the crack tip with crack offset distance has been studied. Due to the presence of a neighbouring crack, two types of interactions viz. intensification and shielding effect have been observed. The interaction between the cracks is seen to be dependent on the crack offset distance. It is seen that the presence of a neighbouring crack results in the appearance of mode II stress intensity factor which was otherwise absent for a single edge crack. It can be said that the proximity of cracks is non-desirable for structural integrity. The von-Mises stress for different crack orientations has been computed. Linear elastic analysis of state of stress around the crack tip has also been done.

Asian Journal of Engineering and Technology, 2015

Composite materials are made from two or more constituent materials with significantly different ... more Composite materials are made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct on a macroscopic level within the finished structure. In the present work a silica-styrene-butadiene rubber hybrid composite material is developed with 1 and 2 wt% of nano sized silica particle and 0.25 to 1.5 wt% of styrene-butadiene rubber mixed in resin. About 75% of wear reduction is found due to addition of silica particle, whereas addition of styrene-butadiene rubber has insignificant effect on the wear rate. However, it slightly increases the wear rate as compared to silica filled epoxy composite. Hybrid composites with higher silica content exhibit higher hardness. A good liner correlation between wear rate and hardness exists with probability p 0.8.

Appl. Soft Comput., 2015

Summary of predicted and experimental results. The crack growth under multiple cracks is highly i... more Summary of predicted and experimental results. The crack growth under multiple cracks is highly influenced by neighbouring cracks.No mathematical relation is available to predict the crack initiation direction.ANN has been used to predict crack growth direction in multiple crack geometry.The effect of degree of input variables and hybrid combination of activation functions is studied.Nonlinear and linear activation functions are used through the one and two-hidden layer ANN.The experimental dataset as first or second degree were used.Higher order input variables are found to be more suitable. The objective of this study is to design an efficient artificial neural network (ANN) architecture in order to predict the crack growth direction in multiple crack geometry. Nonlinear logistic (sigmoid and tangent hyperbolic) and linear activation functions have been used through the one- and two-hidden layer ANN. 85 tests were conducted on aluminium alloys under different crack positions, defi...

Journal of the Mechanical Behavior of Materials, 2020

Present work studies the effect of particle reinforcement on fracture toughness of bio-composites... more Present work studies the effect of particle reinforcement on fracture toughness of bio-composites. The filler used has been taken as rice husk. Epoxy resin has been taken as matrix material. Composites with varying filler loading of 10, 20, 30 and 40 wt.% were fabricated. The fracture toughness was seen to be increasing with increase in filler loading. However beyond 20% there was a decrease in fracture toughness with increase in filler loading. The effect of fibre treatment on toughness was also observed. Rice husk fibres pre-treated with NaOH were used. It was observed that fracture toughness further improved due to treatment. The increase in fracture toughness was significant. Fracture toughness increased from 1.072 to 2.7465 MPa√mm for 20% reinforcement and after treatment it increased to 2.876 MPa√mm. It was observed that concentration of treatment media also affects the fracture toughness. Further the effect of hybridization was observed by addition of rice husk ash as a secon...

In the present investigation temperature dependence fatigue strength behaviour of Inconel 825 sup... more In the present investigation temperature dependence fatigue strength behaviour of Inconel 825 super alloys is investigated. Based on the experimental results different S-N models have been derived and suitable model for the prediction of fatigue strength have been proposed. An inverse power and exponential relation between fatigue strength and absolute temperature is demonstrated. The proposed models are used to predict the fatigue life using well known Palmgren-Miner rule. Based on high to low and low to high load steps test data sets under identical test conditions, Miner rule based statistical damage constant is stochastically modeled for fatigue life prediction at different level of probability and validated. The modeling process combines a probabilistic fatigue damage accumulation and a stress-life-temperature relation technique.

Open Health

COVID-19 viruses are primarily transmitted between people via respiratory droplets generated from... more COVID-19 viruses are primarily transmitted between people via respiratory droplets generated from an infected person while coughing, sneezing, exhaling or close contact. Hence, the use of masks are part of prevention and control measures to limit the spread of COVID-19. A comprehensive study on various materials used in masks is required. The filtration efficiency of cotton masks increases with increase in thread count and number of layers, but breathability is affected and therefore a risk for longer durations. Cotton-based masks have filtration efficiency ranging from 5% to 80% depending on the number of layers. Combinations of different hybrid fabric materials and design have an efficiency ranging from 37% to 97%. Bio-cellulose, which is derived from cellulosic biomass by synthesis techniques involving various physical and chemical processes followed by refining techniques, possesses remarkable properties including biodegradability, biocompatibility, low toxicity, etc., making it...

Veterinary Surgery

OBJECTIVE Quantitation of mechanical properties of a novel locking compression plate (LCP) for bo... more OBJECTIVE Quantitation of mechanical properties of a novel locking compression plate (LCP) for bovine tibia. STUDY DESIGN Prospective in vitro study. SAMPLE POPULATION Adult Murrah buffalo (250-350 kg) tibiae. METHODS Forty tibiae were randomly assigned to five treatment groups (n = 8/group): intact bone and bone constructs with a standard nonlocking plate, single LCP, double LCP, and novel LCP. During implant application, a mid-diaphyseal, oblique osteotomy was performed in all constructs, which were subsequently tested in axial compression (n = 4 each) or three-point craniocaudal bending (n = 4 each). Novel LCP alone (n = 4) was tested only in bending. Stiffness, yield load, ultimate failure load, and bending moment were determined from the load deformation curves and compared among different treatment groups (P < .05). RESULTS Under compression, yield load of the novel LCP (24.07 ± 3.45 kN) was greater than that of the nonlocking plate (11.10 ± 2.46 kN) and the single LCP (18.01 ± 2.07 kN) but less than that of the double LCP (30.61 ± 1.95 kN), and ultimate failure load of the novel LCP (25.85 ± 4.32 kN) was greater than that of the nonlocking plate (13.18 ± 2.91 kN) but similar to that of the single LCP (21.17 ± 2.33 kN) and the double LCP (32.40 ± 1.46 kN). Bending moment, yield load, and ultimate failure load of the novel LCP were 565.37 ± 79.30 Nm, 7.90 ± 1.14 kN, 9.83 ± 1.38 kN, respectively, which were greater than those of the nonlocking plate and the single LCP but comparable to those of the double LCP. CONCLUSION The novel LCP developed for bovine tibia was mechanically superior to the standard nonlocking plate or the single LCP and comparable to the double LCP. CLINICAL SIGNIFICANCE The novel LCP may provide rigid fixation of tibial diaphyseal fractures in buffaloes and cattle weighing 250 to 350 kg.

Fatigue & Fracture of Engineering Materials & Structures

Journal of the Mechanical Behavior of Materials, Jun 9, 2018

Abstract Friction stir welding (FSW) is a solid-state joining which reduces the structural weight... more Abstract Friction stir welding (FSW) is a solid-state joining which reduces the structural weight significantly and hence it has received worldwide attention for the joining of aluminium alloys. In this paper, fatigue tests and finite element analysis were employed to study the mechanical and fatigue properties of a friction stir welded T-joint of 19501 aluminium alloy. An LS-2 FSW machine with 100 kN capacity was used to fabricate the T and butt joints. The tensile properties of the friction stir welded joint show that there is a marginal reduction of about 5% in strength and ductility as compared to an un-welded 19501 aluminium alloy. S-N test results of theT-joint specimen at two stress ratios of 0 and −1 showed that there was a reduction of 15% in the fatigue strength due to the change of stress ratio from 0 to −1. The effect of mean stress can be well approximated using Goodman’s criterion as compared to Gerber’s or Soderberg’s criteria. The predicted fatigue lives from the proposed model using the Palmgren-Miner rule (PMR) were found to be within reasonable accuracy. Micrographs shown for the fracture surfaces of the retreating side, mid-weld zone and the advancing side of the T-joint indicate that fracture surfaces are a mixture of dimple and cleavage features.

International Journal for Computational Methods in Engineering Science and Mechanics

ABSTRACT The fatigue crack growth model is expressed as a function of mechanical properties. The ... more ABSTRACT The fatigue crack growth model is expressed as a function of mechanical properties. The uncertainties associated with the crack growth process are incorporated assuming them as random variable following a statistical distribution. The effect of material nonhomogeneity is included in the model through a random process parameter of Gaussian type. Assuming fatigue life as a random variable, probability-confidence bounded mean crack growth relation is developed and an algorithm is presented. The model is validated through the experimental and predicted results from several data sets.

Journal of the Mechanical Behavior of Materials

Natural fibers from agricultural waste have received more attraction than traditional synthetic f... more Natural fibers from agricultural waste have received more attraction than traditional synthetic fibers in recent years. In present investigation epoxy/rice husk composite has been fabricated to utilize the agricultural waste which can be recycled easily and overcome the pollution problems due to smoke and fine silica ash. Study of interfacial bonding and dispersion of rice husk in epoxy resin has been studied through scanning electron microscope image. Characterization of fabricated composites has been done by mechanical properties. Ultimate tensile strength, Young’s Modulus and hardness are highest at 10 wt.% of rice husk particle and their values are 66.5 MPa, 616.46 MPa and 16.8 HV respectively. Machinability of epoxy/rice husk composites has been determined through drilling operation. Effect of feed rate (0.1, 0.2 and 0.3 mm/rev), speed (300, 600 and 900 rpm) and wt.% of reinforcement (10, 15 & 20) have been studied on machinability of epoxy/rice husk composites. Taguchi L27 ort...

Engineering Science and Technology, an International Journal

Abstract The statistical aspect of mode I, mode II and mixed mode I/II fracture toughness of epox... more Abstract The statistical aspect of mode I, mode II and mixed mode I/II fracture toughness of epoxy based bio-composite reinforced with 20 wt% walnut shell particle and 10 wt% coconut fiber is studied. The bio-composite is fabricated by the squeeze casting method. A series of fracture tests are conducted on hybrid bio-composite using three point bend, four point bend and semicircular arc bend specimen. The statistical distribution of normalized geometry parameters, T stress, crack tip plastic zone size, particle and fiber size are studied. Generalized maximum tangential stress criterion is modified considering the stochastic nature of the geometry and strength parameters assuming them to follow two parameters Weibull probability distribution. The model developed is applied to the bio-composite and predicted results are compared with the experimental values. Very good agreement is found between the experimental results and predicted results. The variability in the fracture toughness values are correlated with the particle and fiber size determined from scanning electron microscopy.

Frattura ed Integrità Strutturale

A finite rectangular plate of unit thickness with two inclined cracks (parallel and non parallel)... more A finite rectangular plate of unit thickness with two inclined cracks (parallel and non parallel) under biaxial mixed mode condition are modelled using finite element method. The finite element method is used for determination of stress intensity factors by ANYSIS software. Effects of crack inclination angle on stress intensity factors for two parallel and non parallel cracks are investigated. The significant effects of different crack inclination parameters on stress intensity factors are seen for lower and upper crack in two inclined crack. The present method is validated by comparing the results from available experimental data obtained by photo elastic method in same condition.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

In this study, the mechanical properties and fatigue life of 19501 aluminum alloy friction stir w... more In this study, the mechanical properties and fatigue life of 19501 aluminum alloy friction stir welded T-joint is investigated. Tensile properties of friction stir welded joint show that there is a marginal reduction of about 5% in strength and ductility as compared to unwelded 19501 aluminum alloy. Fatigue test results of T-joint specimen at two stress ratios of 0 and -1 show that there is a reduction of 15% in fatigue strength due to change of stress ratio from -1 to 0. Also, higher variation is seen in fatigue strength in low cycle zone than the high cycle zone. Effect of mean stress on fatigue life is discussed on the basis of different mean stress effect models. Morrow’s mean stress effect model is found to be better than other models. Micrographs from the fracture surfaces of retreating side, mid weld zone, and advancing side of the T-joint indicates that fracture surfaces are cleavage fracture. Different sizes of inter-metallic bonding are seen in the micrographs, which indic...

International Journal of Engineering Research and Applications

Engineering materials having two or more different physical or chemical properties make co mposit... more Engineering materials having two or more different physical or chemical properties make co mposites. In recent years natural fibres from agricultural waste have received more attraction as they offer number of advantages over traditional synthetic fibres. The proposed study has great use of agricultural waste which can be recycled easily and is environmental friendly also. A bio-co mposite reinforced with rice husk, rice husk particulate and mixtu re of husk and particulate i.e. hybrid in epo xy resin has been fabricated. The decrease in Ultimate Tensile Strength, Young's Modulus and % Elongation was observed with increase in wt. %. U ltimate Tensile Strength, Young's Modulus and % Elongation was recorded 66.5 MPa, 616.46 MPa and 10.6% respectively at 10%wt of rice husk particle reinforced co mposite.

Journal of Reinforced Plastics and Composites

The effect of bio-fibres and bio-particles on the fracture toughness has been investigated. Epoxy... more The effect of bio-fibres and bio-particles on the fracture toughness has been investigated. Epoxy resin is used as matrix material and different bio-fibers such as banana fiber, bagasse fiber, coconut fiber and particles such as silica and walnut shell particle with different wt% are added as reinforcing material. The mode I fracture toughness tests are conducted in a servo hydraulic universal testing machine. The results show that the fracture toughness of bio-composites reinforced with 20 wt% bagasse or 10 wt% coconut fiber are 1.108 MPa √ m and 1.094 MPa √ m, respectively which are about 8% and 7% higher than neat epoxy. Addition of 2 wt% of silica with 20 wt% of bagasse shows 60% increment of fracture toughness with respect to bagasse and 72% increment with respect to neat epoxy. Hybridisation of bagasse with banana fibers shows 54% decrease in fracture toughness as compared to bagasse and 13% increase as compared to banana. The overall fracture toughness of hybrid bio-composite...

Procedia Engineering, 2017

Abstract The increased application of aluminum alloy in the past decades in automotive industries... more Abstract The increased application of aluminum alloy in the past decades in automotive industries has suggested the researchers to study its behavior under different loading conditions and applications. Tungsten inert gas (TIG) welding in aluminum alloy is one of the widely used methods to manufacture the automobile parts. The strength of welded components may differ under different loading conditions. Moreover, if cracks develop in the welded components during their service period, it makes the working conditions worst. The working efficiency of same component may differ at different strain rates. The effect of strain rate on the fracture behavior of aluminum alloy containing cracks or notches is important to be studied to predict the failure of the component. The present work describes an experimental investigation to study the influence of high strain rates on the fracture behavior and tensile properties of welded 6061 aluminum alloy. The tensile tests have been performed on 100 kN Universal Testing Machine under uniaxial static loading. At higher strain rates, considerable increase in yield strength and ultimate tensile strength has been observed. This may be due to insufficient elastic recovery time at higher crosshead speed, and thus the yield as well as ultimate strength of the material increases.