Archive for the ‘Mechanical Engineering Artycles’ Category
Study of the response of fiber reinforced polymeric composite beam under dynamic loading and hydrothermal environment
February 25th, 2008
title: Study of the response of fiber reinforced polymeric composite beam under dynamic loading and hydrothermal environment authors: Kagi, Bahubali Chandrashekar
abstract: Fiber reinforced polymeric (FRP) composites are beginning to find applications in constructing infrastructures such as bridges, railroads, etc. Composites may potentially be more durable replacements for steel and concrete, but their experience in these applications is minimal. Also, composite decks are susceptible to change in environmental conditions. Thus, the study of the behavior of composite material in elevated environmental conditions is necessary. This thesis is aimed at development and validation of Finite element methods used to analyze Fiber reinforced polymeric composite beam under moisture and elevated temperature change. The response of the composite beam subjected to various loads is analyzed under dry and moist conditions. It is assumed that only the matrix properties are adversely affected. The mechanical properties such as stiffness, strength, etc are degraded due to the combined effect of moisture and temperature change. The laminate properties are calculated using the rule of mixtures. A parametric study is carried out by varying the fiber volume fraction and by changing the fiber orientations and ply lay-ups in the laminate. From results it can be observed that the static and dynamic deflections increase due to the presence of moisture and increased temperature. The behavior of the beam is also influenced by the ply orientations and fiber volume fraction. Thus, for composite materials to reach their full potential in structural applications, it becomes quite imperative to consider factors such as moisture content, temperature, ply orientations and fiber volume during design and analysis.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: Fiber reinforced polymeric (FRP) composites are beginning to find applications in constructing infrastructures such as bridges, railroads, etc. Composites may potentially be more durable replacements for steel and concrete, but their experience in these applications is minimal. Also, composite decks are susceptible to change in environmental conditions. Thus, the study of the behavior of composite material in elevated environmental conditions is necessary. This thesis is aimed at development and validation of Finite element methods used to analyze Fiber reinforced polymeric composite beam under moisture and elevated temperature change. The response of the composite beam subjected to various loads is analyzed under dry and moist conditions. It is assumed that only the matrix properties are adversely affected. The mechanical properties such as stiffness, strength, etc are degraded due to the combined effect of moisture and temperature change. The laminate properties are calculated using the rule of mixtures. A parametric study is carried out by varying the fiber volume fraction and by changing the fiber orientations and ply lay-ups in the laminate. From results it can be observed that the static and dynamic deflections increase due to the presence of moisture and increased temperature. The behavior of the beam is also influenced by the ply orientations and fiber volume fraction. Thus, for composite materials to reach their full potential in structural applications, it becomes quite imperative to consider factors such as moisture content, temperature, ply orientations and fiber volume during design and analysis.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
Experimental investigation and analysis for bearing strength behavior of composite laminates
December 19th, 2007
title: Experimental investigation and analysis for bearing strength behavior of composite laminates authors: Yeole, Amit
abstract: An investigation of joint strength in bolted connections for Carbon unitape material [0/45/-45/90]3s is presented. The simple case of bearing double shear joint is considered. In the first stage the objective of work was to test three different material configurations with three lay up sequences and further reduce to one material and one lay up sequence which yields maximum Bearing strength. Further this material with maximum bearing strength was used to study the effects of various geometrical parameters such as edge to width ratio, width to diameter ratio, hole clearance, external factors such as temperature and clamp up force on the bearing strength. The second objective of thesis was to build a 3D finite element model for the quasi-isotropic material, validate the results with the experimental results and provide a future scope to use this model for various combinations of material and parametric studies.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: An investigation of joint strength in bolted connections for Carbon unitape material [0/45/-45/90]3s is presented. The simple case of bearing double shear joint is considered. In the first stage the objective of work was to test three different material configurations with three lay up sequences and further reduce to one material and one lay up sequence which yields maximum Bearing strength. Further this material with maximum bearing strength was used to study the effects of various geometrical parameters such as edge to width ratio, width to diameter ratio, hole clearance, external factors such as temperature and clamp up force on the bearing strength. The second objective of thesis was to build a 3D finite element model for the quasi-isotropic material, validate the results with the experimental results and provide a future scope to use this model for various combinations of material and parametric studies.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
Design of a two stage epicyclic gearbox in sintered metal gears
December 19th, 2007
title: Design of a two stage epicyclic gearbox in sintered metal gears authors: Vatkar, Shirish
abstract: The goal of this thesis was to research and develop epicyclic spur gearbox for sintering manufacturing process. Sintered type of manufacturing process has been in place for quite a long time, though its usage has been limited by knowledge in the material, processes and design of these parameters integrated together for optimization. The pages to follow provide information on Sintering process and the design of gear parts. The focus has been to investigate different type of sinter materials and design a 2-stage gearbox with high efficiency. Other aim is also to showcase the advantage of using methods of manufacturing that save cost and provide a reliable product.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: The goal of this thesis was to research and develop epicyclic spur gearbox for sintering manufacturing process. Sintered type of manufacturing process has been in place for quite a long time, though its usage has been limited by knowledge in the material, processes and design of these parameters integrated together for optimization. The pages to follow provide information on Sintering process and the design of gear parts. The focus has been to investigate different type of sinter materials and design a 2-stage gearbox with high efficiency. Other aim is also to showcase the advantage of using methods of manufacturing that save cost and provide a reliable product.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
Finite element analysis of innovated design of racing brake calipers
December 19th, 2007
title: Finite element analysis of innovated design of racing brake calipers authors: Tyagi, Parshant
abstract: The work in this study involves a conceptual design of a disc brake system. Disc brakes offer higher performance braking, simpler design, lighter weight, and better resistance to water interference than drum brakes. The objective is to find out the best conceptual caliper model design, with different materials and by subjecting them to same loading conditions, takin displacements and stresses into account. The study utilized different materials for three different conceptual models. The materials that were analyzed were Aluminum 2219-T87, Aluminum 6061-T651 and Graphite Silicon Carbide Aluminum Metal Matrix Composite (GrA-Ni). All the three different brake calipers were subjected to the same load conditions for each new material. The results were analyzed for given set of load conditions and were studied for displacements and stresses. The calipers were analyzed for pressure and tangential loads and the results were studied for deformation of the caliper body under stress. The results for the different models with different materials were compared to conclude the model with lowest deformation under same loading conditions.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: The work in this study involves a conceptual design of a disc brake system. Disc brakes offer higher performance braking, simpler design, lighter weight, and better resistance to water interference than drum brakes. The objective is to find out the best conceptual caliper model design, with different materials and by subjecting them to same loading conditions, takin displacements and stresses into account. The study utilized different materials for three different conceptual models. The materials that were analyzed were Aluminum 2219-T87, Aluminum 6061-T651 and Graphite Silicon Carbide Aluminum Metal Matrix Composite (GrA-Ni). All the three different brake calipers were subjected to the same load conditions for each new material. The results were analyzed for given set of load conditions and were studied for displacements and stresses. The calipers were analyzed for pressure and tangential loads and the results were studied for deformation of the caliper body under stress. The results for the different models with different materials were compared to conclude the model with lowest deformation under same loading conditions.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
Evaluation of the occupant response and structural damage according to the newly proposed pole test under Federal Motor Vehicle Safety Standard side impact regulation
December 19th, 2007
title: Evaluation of the occupant response and structural damage according to the newly proposed pole test under Federal Motor Vehicle Safety Standard side impact regulation authors: Siruvole, Sandeep Kumar
abstract: Every year around the world various types of automobile accidents occur, out of which side impact vehicular collisions are the most severe. Of these, side crashes into fixed narrow objects like trees, poles account for quarter percent of total deaths and serious injuries. Moreover these side impacts present a difficult problem for improving automotive crashworthiness because of the limited crushable zone between the vehicle occupant and the intruding door structure. To improve the automotive safety in side impacts a new pole test has been proposed under Federal Motor Vehicle Safety Standard (FMVSS) 214 to make the existing regulation more comprehensive in addressing the critical head and neck injuries in addition to thoracic and pelvis injuries. In this thesis, a finite element model of the Ford Taurus and Moving Deformable Barrier (MDB) as developed by National Crash Analysis Center (NCAC) has been used for the impact analysis. The US DOT-SID side impact dummy taken from MADYMO dummy database has been used as the vehicle occupant and the rigid pole modeled in MSC. Patran software as the narrow object. Computer Simulations have been analyzed according to the new proposed pole test and (FMVSS) 214 regulation. The critical injury values, the occupant kinematics and the structural damage have been compared justifying the need for the new pole test for improving the occupant safety.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: Every year around the world various types of automobile accidents occur, out of which side impact vehicular collisions are the most severe. Of these, side crashes into fixed narrow objects like trees, poles account for quarter percent of total deaths and serious injuries. Moreover these side impacts present a difficult problem for improving automotive crashworthiness because of the limited crushable zone between the vehicle occupant and the intruding door structure. To improve the automotive safety in side impacts a new pole test has been proposed under Federal Motor Vehicle Safety Standard (FMVSS) 214 to make the existing regulation more comprehensive in addressing the critical head and neck injuries in addition to thoracic and pelvis injuries. In this thesis, a finite element model of the Ford Taurus and Moving Deformable Barrier (MDB) as developed by National Crash Analysis Center (NCAC) has been used for the impact analysis. The US DOT-SID side impact dummy taken from MADYMO dummy database has been used as the vehicle occupant and the rigid pole modeled in MSC. Patran software as the narrow object. Computer Simulations have been analyzed according to the new proposed pole test and (FMVSS) 214 regulation. The critical injury values, the occupant kinematics and the structural damage have been compared justifying the need for the new pole test for improving the occupant safety.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
Use of SPH and Lagrangian meshing technique to assess damage area in bumper shields impacted by hypervelocity space debris
December 17th, 2007
title: Use of SPH and Lagrangian meshing technique to assess damage area in bumper shields impacted by hypervelocity space debris authors: Seram, Sai Bhargavi
abstract: Space debris are objects in Earth’s orbit consisting of fragments of spent rocket stages, non-functional satellites, and parts like fasteners, paint chips and other waste materials in the lower earth orbits (LEO) (200 – 2000 km/s) traveling at hypervelocity with maximum speeds of 16 km/s. These objects can cause considerable damage to spacecraft structure, the Space Shuttle and the International Space Station which are orbiting around the earth at altitudes of 300 to 500 km/s in the LEO. Damage occurs when the debris traveling at hypervelocity impact (HVI) the spacecraft structure. Hence there is necessity to not only develop spacecraft with good shielding, but also develop a means of spacecraft pressure wall repair. A NASA EPSCoR grant for designing a portable friction stir welder to repair the hypervelocity impact damage caused was the driving force for this thesis topic. A detailed understanding of the extent of damage to the spacecraft shielding system was necessary to understand repair requirements expected for the design of a space-bound Friction Stir Welder. A spacecraft shielding system can consist of a double bumper shielding system placed ahead of the pressure wall. The current goal of this study was to determine the damage area of the pressure wall, using the new grid less Smoothed Particle Hydrodynamics (SPH) meshing techniques and the regular Lagrangian meshing technique. The approach was to model and validate the damage area due to the HVI against existing test data, and to conduct a parametric study for various impactor shapes, velocities and impact scenarios. The software tools used for modeling were PATRAN for the Lagrangian models and LS-Prepost for SPH modeling. The simulation was analyzed in LS-DYNA, a non-linear finite element dynamic analyzer. Simulations were initially conducted using a spherical projectile; later parametric studies were conducted with varied impactor shapes. The materials for the plate and impactor were alloys of Al (6061-T6, l100-O, 2024-T4). It was observed that the model developed using SPH meshing technique generated the debris cloud as in the actual impact scenario, unlike the Lagrangian meshing technique which had problems with mesh tangles. Hence the SPH technique provided a potential means of predicting pressure wall damage due to HVI.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: Space debris are objects in Earth’s orbit consisting of fragments of spent rocket stages, non-functional satellites, and parts like fasteners, paint chips and other waste materials in the lower earth orbits (LEO) (200 – 2000 km/s) traveling at hypervelocity with maximum speeds of 16 km/s. These objects can cause considerable damage to spacecraft structure, the Space Shuttle and the International Space Station which are orbiting around the earth at altitudes of 300 to 500 km/s in the LEO. Damage occurs when the debris traveling at hypervelocity impact (HVI) the spacecraft structure. Hence there is necessity to not only develop spacecraft with good shielding, but also develop a means of spacecraft pressure wall repair. A NASA EPSCoR grant for designing a portable friction stir welder to repair the hypervelocity impact damage caused was the driving force for this thesis topic. A detailed understanding of the extent of damage to the spacecraft shielding system was necessary to understand repair requirements expected for the design of a space-bound Friction Stir Welder. A spacecraft shielding system can consist of a double bumper shielding system placed ahead of the pressure wall. The current goal of this study was to determine the damage area of the pressure wall, using the new grid less Smoothed Particle Hydrodynamics (SPH) meshing techniques and the regular Lagrangian meshing technique. The approach was to model and validate the damage area due to the HVI against existing test data, and to conduct a parametric study for various impactor shapes, velocities and impact scenarios. The software tools used for modeling were PATRAN for the Lagrangian models and LS-Prepost for SPH modeling. The simulation was analyzed in LS-DYNA, a non-linear finite element dynamic analyzer. Simulations were initially conducted using a spherical projectile; later parametric studies were conducted with varied impactor shapes. The materials for the plate and impactor were alloys of Al (6061-T6, l100-O, 2024-T4). It was observed that the model developed using SPH meshing technique generated the debris cloud as in the actual impact scenario, unlike the Lagrangian meshing technique which had problems with mesh tangles. Hence the SPH technique provided a potential means of predicting pressure wall damage due to HVI.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
Modeling and analysis of a composite B-Pillar for side-impact protection of occupants in a sedan
December 17th, 2007
title: Modeling and analysis of a composite B-Pillar for side-impact protection of occupants in a sedan authors: Reddy, Santosh
abstract: Cars safety became an issue almost immediately after the invention of the automobile. To protect occupants from a direct impact, the passenger compartment and the structure of the vehicle should keep its shape in a crash. Continuous developments to improve is proposed everyday, standards are set in pertinent to different crash scenarios such as the frontal crash, side impact and so on. Among these standards, side impact is one of the most fatal crash scenarios that lead to death of people in the United States and across the globe. In the contemporary world, fuel consumption also poses a serious issue that has to be considered. With these constraints in consideration, a lighter and stronger material than steel, the composite material, can be used. Using this material would help in reducing the fuel efficiency without sacrificing the safety of the vehicle. With the advance in computer simulations, finite element (FE) model of the Ford Taurus and Moving Deformable Barrier (MDB) developed by the National Crash Analysis Center (NCAC) has been used for different impact scenarios to predict the vehicle behavior and occupant response. In addition, MSC Patran has been used as the modeler and LS-Dyna as the solver to run the required simulations. MADYMO is used to predict the injury parameters. In this research, a composite B-Pillar that is the energy absorbing structure is modeled and analyzed with Finite Element Analysis. The injuries sustained by the occupant are predicted using Madymo. An attempt is made to use carbon and glass fiber composite materials in the B-Pillar modeled in this study. In addition, a parametric study is carried out on the B-Pillar to determine the maximum possible energy absorbing parameters. It is demonstrated that the new modeling with the use of carbon/glass with a pertinent orientation and thickness may present more energy absorption than the present steel pillar. Energy absorption, displacement and the acceleration of the present and the new model are also compared and discussed in detail. Occupant injuries, such as chest and head injuries are compared for the vehicle occupants with present and the new model. It is demonstrated that the new B-Pillar composite model with carbon may be more effective than the present steel pillar.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering
abstract: Cars safety became an issue almost immediately after the invention of the automobile. To protect occupants from a direct impact, the passenger compartment and the structure of the vehicle should keep its shape in a crash. Continuous developments to improve is proposed everyday, standards are set in pertinent to different crash scenarios such as the frontal crash, side impact and so on. Among these standards, side impact is one of the most fatal crash scenarios that lead to death of people in the United States and across the globe. In the contemporary world, fuel consumption also poses a serious issue that has to be considered. With these constraints in consideration, a lighter and stronger material than steel, the composite material, can be used. Using this material would help in reducing the fuel efficiency without sacrificing the safety of the vehicle. With the advance in computer simulations, finite element (FE) model of the Ford Taurus and Moving Deformable Barrier (MDB) developed by the National Crash Analysis Center (NCAC) has been used for different impact scenarios to predict the vehicle behavior and occupant response. In addition, MSC Patran has been used as the modeler and LS-Dyna as the solver to run the required simulations. MADYMO is used to predict the injury parameters. In this research, a composite B-Pillar that is the energy absorbing structure is modeled and analyzed with Finite Element Analysis. The injuries sustained by the occupant are predicted using Madymo. An attempt is made to use carbon and glass fiber composite materials in the B-Pillar modeled in this study. In addition, a parametric study is carried out on the B-Pillar to determine the maximum possible energy absorbing parameters. It is demonstrated that the new modeling with the use of carbon/glass with a pertinent orientation and thickness may present more energy absorption than the present steel pillar. Energy absorption, displacement and the acceleration of the present and the new model are also compared and discussed in detail. Occupant injuries, such as chest and head injuries are compared for the vehicle occupants with present and the new model. It is demonstrated that the new B-Pillar composite model with carbon may be more effective than the present steel pillar.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering
Study of rear impact in light trucks and potential injuries to the occupants
December 7th, 2007
title: Study of rear impact in light trucks and potential injuries to the occupants authors: Patel, Dhruv Vikram
abstract: According to National Highway Traffic Safety Administration (NHTSA), each year about 400,000 trucks are involved in motor vehicle crashes. Eighteen percent of these accidents are in rear-end crashes of the trucks. Accordingly, fatal injury had resulted to 5 percentages of the injuries. Whiplash is the common neck injury in rear impact consuming billions of dollars in insurance. However due to relatively low number of deaths or injuries in rear impact crashes, NHTSA does not conduct any rear impact testing to test the bumpers. The main objective of this thesis is to study the effects of low speed impact on light trucks and the potential injuries on the occupants. The Federal Motor Vehicle Safety Standards (FMVSS) includes rear impact testing of fuel leakage, but only has a voluntary test for rear bumper impact test at low speed. In this thesis, the low speed rear impact simulation of a light truck was performed to understand the bumper deformation. A Chevy light truck is impacted to a flat barrier at 5 mph by using the finite element code LS-Dyna. This simulation is analyzed and validated for its bumper impact test. A parametric study is thus performed to quantify the effect of various parameters on the rear end impact of the truck. Four vehicles were selected from public domain National crash analysis center (NCAC). These vehicles were Geo Metro, Chevy Truck, Ford Taurus and Ford single unit truck, selected according to the weight of the vehicles. The Chevy truck was chosen as target vehicle and other three models were selected as bullet vehicles. The target vehicle was then impacted with speed of 5, 10 and 15 mph. The accelerations were extracted from the center of gravity of the target vehicle (Chevy Truck). The acceleration pulses from the LS-Dyna were used in multi body analysis Mathematical Dynamic Model (Madymo). The seat model was built with similar characteristics as the Chevy truck seat. A Hybrid ΙΙΙ dummy model was positioned with seat and the model was given the acceleration pulses from the corresponding g’s at low speed for the truck impacted at 5, 10 and 15 mph. This model was used to study the injuries on the neck. The developed model was then compared for neck response from the occupant with head restraint and without head restraint. Output of the dummy response resulted in injury values needed to be studied. The injury values were compared with standard critical values complying with injuries. The result of this study can be utilized to obtain the effect of weight of impacting vehicles in low speed rear crashes of trucks. The impact response of the occupants and potential neck loads and injuries are also by products of this study
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: According to National Highway Traffic Safety Administration (NHTSA), each year about 400,000 trucks are involved in motor vehicle crashes. Eighteen percent of these accidents are in rear-end crashes of the trucks. Accordingly, fatal injury had resulted to 5 percentages of the injuries. Whiplash is the common neck injury in rear impact consuming billions of dollars in insurance. However due to relatively low number of deaths or injuries in rear impact crashes, NHTSA does not conduct any rear impact testing to test the bumpers. The main objective of this thesis is to study the effects of low speed impact on light trucks and the potential injuries on the occupants. The Federal Motor Vehicle Safety Standards (FMVSS) includes rear impact testing of fuel leakage, but only has a voluntary test for rear bumper impact test at low speed. In this thesis, the low speed rear impact simulation of a light truck was performed to understand the bumper deformation. A Chevy light truck is impacted to a flat barrier at 5 mph by using the finite element code LS-Dyna. This simulation is analyzed and validated for its bumper impact test. A parametric study is thus performed to quantify the effect of various parameters on the rear end impact of the truck. Four vehicles were selected from public domain National crash analysis center (NCAC). These vehicles were Geo Metro, Chevy Truck, Ford Taurus and Ford single unit truck, selected according to the weight of the vehicles. The Chevy truck was chosen as target vehicle and other three models were selected as bullet vehicles. The target vehicle was then impacted with speed of 5, 10 and 15 mph. The accelerations were extracted from the center of gravity of the target vehicle (Chevy Truck). The acceleration pulses from the LS-Dyna were used in multi body analysis Mathematical Dynamic Model (Madymo). The seat model was built with similar characteristics as the Chevy truck seat. A Hybrid ΙΙΙ dummy model was positioned with seat and the model was given the acceleration pulses from the corresponding g’s at low speed for the truck impacted at 5, 10 and 15 mph. This model was used to study the injuries on the neck. The developed model was then compared for neck response from the occupant with head restraint and without head restraint. Output of the dummy response resulted in injury values needed to be studied. The injury values were compared with standard critical values complying with injuries. The result of this study can be utilized to obtain the effect of weight of impacting vehicles in low speed rear crashes of trucks. The impact response of the occupants and potential neck loads and injuries are also by products of this study
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
Simulation of potential injuries due to fall at the aircraft entry door
December 5th, 2007
title: Simulation of potential injuries due to fall at the aircraft entry door authors: Dhillon, Kyle
abstract: Falls are one of the most common causes of injury among young children and have been recognized as a major cause of death and disability worldwide among children 1-3 years old. A characteristic of injuries among very young children is that aspects of their normal behavior, such as natural curiosity or physiologic development of their motor skills, could be associated with an increased injury risk, especially in non-friendly and new environments. It has been reported that there have been incidents when children fell from the entry stairs while boarding an airplane. The small size and unpredictable nature of children combined with the size of the gap in the handrails creates risk for children to fall. Falls have long been studied in relation to nursery equipment and playground equipment from heights less than 1-2 meters, but not where the ground is asphalt or concrete. The present study aims to assess fall-related injuries among children on a concrete the airport tarmac. Since little is known regarding the biomechanics of such falls and injury risk associated with them, computer simulation provides a valuable tool to investigate and predict injury outcomes. The validity of the model is crucial to the reliability of the outcome. In this study, a computer simulation of a child falling from a step of the stair surface onto a hard surface was analyzed for head accelerations using the MADYMO Hybrid III-3 Year Old Child dummy model. There was no crash pulse applied, gravity was used as the fall force. Automotive and aerospace companies perform tests and computer simulations in order to optimize and design safety devices in their vehicles. This study investigates the fall injury related parameters for the head and neck, as well as the influence of contact friction forces between the dummy and surface, the kinematics of the fall, and on the head and neck acceleration forces. This study may result in an increased study of passenger safety.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: Falls are one of the most common causes of injury among young children and have been recognized as a major cause of death and disability worldwide among children 1-3 years old. A characteristic of injuries among very young children is that aspects of their normal behavior, such as natural curiosity or physiologic development of their motor skills, could be associated with an increased injury risk, especially in non-friendly and new environments. It has been reported that there have been incidents when children fell from the entry stairs while boarding an airplane. The small size and unpredictable nature of children combined with the size of the gap in the handrails creates risk for children to fall. Falls have long been studied in relation to nursery equipment and playground equipment from heights less than 1-2 meters, but not where the ground is asphalt or concrete. The present study aims to assess fall-related injuries among children on a concrete the airport tarmac. Since little is known regarding the biomechanics of such falls and injury risk associated with them, computer simulation provides a valuable tool to investigate and predict injury outcomes. The validity of the model is crucial to the reliability of the outcome. In this study, a computer simulation of a child falling from a step of the stair surface onto a hard surface was analyzed for head accelerations using the MADYMO Hybrid III-3 Year Old Child dummy model. There was no crash pulse applied, gravity was used as the fall force. Automotive and aerospace companies perform tests and computer simulations in order to optimize and design safety devices in their vehicles. This study investigates the fall injury related parameters for the head and neck, as well as the influence of contact friction forces between the dummy and surface, the kinematics of the fall, and on the head and neck acceleration forces. This study may result in an increased study of passenger safety.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
Parametric study of load transfer in two-bolted single lap hybrid (bonded/bolted) shear joints
December 5th, 2007
title: Parametric study of load transfer in two-bolted single lap hybrid (bonded/bolted) shear joints authors: Ganji, Nagesh
abstract: A composite material can be defined as two or more materials combined to form another material with enhanced properties. A composite material shows high strength to weight ratio, light weight, tailored properties, high stiffness, high corrosion resistance and high fatigue life. In the recent past, the usage of composite materials in the aviation industry has been increasing and most of the lap joints are being used in aircraft fuselage. This study mainly focuses on the load transfer in hybrid (bonded/bolted) joints when they are subjected to tensile load. It is difficult to calculate the load transfer in hybrid (bonded/bolted) joints because of the difference in stiffness of the varied loads. A three dimensional Finite Element (FE) model has been developed to compute the load transfer in hybrid composite single lap joint. This model has been validated by comparing the results of FE model with experimental results for single bolted hybrid lap joint. A parametric study is done next to investigate the effects of various parameters such as material properties, tensile load, adherend thickness, bolt diameter and overlap length on load transfer by bolt. It is observed that hybrid joining (the combination of mechanical fastening and adhesive bonding) can provide enhanced structural performance, when compared to adhesive bonding. This study also discusses the modeling of contact between the bolt and hole and nonlinear material behavior of the model. The parametric study also quantifies relationship between the load transfer and adherend thickness, bolt diameter, tensile load, material properties and overlap length.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
abstract: A composite material can be defined as two or more materials combined to form another material with enhanced properties. A composite material shows high strength to weight ratio, light weight, tailored properties, high stiffness, high corrosion resistance and high fatigue life. In the recent past, the usage of composite materials in the aviation industry has been increasing and most of the lap joints are being used in aircraft fuselage. This study mainly focuses on the load transfer in hybrid (bonded/bolted) joints when they are subjected to tensile load. It is difficult to calculate the load transfer in hybrid (bonded/bolted) joints because of the difference in stiffness of the varied loads. A three dimensional Finite Element (FE) model has been developed to compute the load transfer in hybrid composite single lap joint. This model has been validated by comparing the results of FE model with experimental results for single bolted hybrid lap joint. A parametric study is done next to investigate the effects of various parameters such as material properties, tensile load, adherend thickness, bolt diameter and overlap length on load transfer by bolt. It is observed that hybrid joining (the combination of mechanical fastening and adhesive bonding) can provide enhanced structural performance, when compared to adhesive bonding. This study also discusses the modeling of contact between the bolt and hole and nonlinear material behavior of the model. The parametric study also quantifies relationship between the load transfer and adherend thickness, bolt diameter, tensile load, material properties and overlap length.
description: Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.