Nondestructive acoustic imaging experiments and three dimensional finite element analyses were performed to study the crack-damage interaction phenomenon of a particle reinforced polymeric composite. Effects of damage size and degree of damage on the mode I stress intensity factor and the local stress fields near the crack tip were evaluated and the damage and crack growth behavior were discussed.
{"title":"Damage Characteristics Near Crack Tip for a Particulate Composite","authors":"C. T. Liu, H. Ho","doi":"10.1115/imece1998-0881","DOIUrl":"https://doi.org/10.1115/imece1998-0881","url":null,"abstract":"\u0000 Nondestructive acoustic imaging experiments and three dimensional finite element analyses were performed to study the crack-damage interaction phenomenon of a particle reinforced polymeric composite. Effects of damage size and degree of damage on the mode I stress intensity factor and the local stress fields near the crack tip were evaluated and the damage and crack growth behavior were discussed.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125545859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper examines the fatigue behavior of the 5-1/2 F.H. threaded connection. The finite element method was used to calculate the static and bending stresses in the pin and box for the purpose of estimating fatigue life of the connection. These stresses were compared with the material properties of the steel and a fatigue life was thereby predicted for a given dogleg. The Gerber criterion was selected as the theoretical basis for combining mean and fluctuating stresses. Mean stress was linearized from the static case associated with the preload from make-up torque. Alternating stress was obtained from applying a bending moment associated with a prescribed dogleg. The last engaged thread in the pin, closest to the shoulder, and the last engaged thread in the box, farthest from the shoulder, were seen to be the sites of maximum stress. The pin stresses govern fatigue life because mean stress is higher than for the box. In a parallel effort, a roll test was set up to examine fatigue life experimentally. A BHA was made up and installed horizontally in the roll machine. The deflection at the threaded connection was measured, and the assembly was rotated at a measured speed until the pin part of the threaded connection failed. Next, the finite element results were compared with roll test data and good agreement was obtained. The data was then extrapolated to generate a graph showing expected life as a function of dogleg severity for the 5-1/2 F.H. connection. Finally, the maximum dogleg for which the connection has a 10 million cycle life was predicted.
{"title":"Fatigue Analysis of 5-1/2 F.H. Threaded Connection","authors":"M. Hommel","doi":"10.1115/imece1998-0891","DOIUrl":"https://doi.org/10.1115/imece1998-0891","url":null,"abstract":"\u0000 This paper examines the fatigue behavior of the 5-1/2 F.H. threaded connection. The finite element method was used to calculate the static and bending stresses in the pin and box for the purpose of estimating fatigue life of the connection. These stresses were compared with the material properties of the steel and a fatigue life was thereby predicted for a given dogleg.\u0000 The Gerber criterion was selected as the theoretical basis for combining mean and fluctuating stresses. Mean stress was linearized from the static case associated with the preload from make-up torque. Alternating stress was obtained from applying a bending moment associated with a prescribed dogleg. The last engaged thread in the pin, closest to the shoulder, and the last engaged thread in the box, farthest from the shoulder, were seen to be the sites of maximum stress. The pin stresses govern fatigue life because mean stress is higher than for the box.\u0000 In a parallel effort, a roll test was set up to examine fatigue life experimentally. A BHA was made up and installed horizontally in the roll machine. The deflection at the threaded connection was measured, and the assembly was rotated at a measured speed until the pin part of the threaded connection failed.\u0000 Next, the finite element results were compared with roll test data and good agreement was obtained. The data was then extrapolated to generate a graph showing expected life as a function of dogleg severity for the 5-1/2 F.H. connection. Finally, the maximum dogleg for which the connection has a 10 million cycle life was predicted.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"32 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131637787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a method for identifying the free-free modes of an unconstrained structure by utilizing the available vibration data of the same constrained structure. In modal formulations for flexible body dynamics, modal data are primary known quantities that must be obtained either experimentally or analytically. For vibration measurements, the flexible body may be constrained differently than its actual conditions in the multibody system. To apply the experimentally obtained modal data to the flexible dynamic model, the available vibration data must be properly identified. For a flexible body model in multibody systems, we may need a set of free-free modal data or constrained modal data depending upon the dynamic formulations. The identification of constrained modes from the free-free vibration data is straight forward, but the reverse process to determine the free-free modes from the constrained vibration data is difficult and expensive. The aim of this study is to extract, based on experimentally obtained vibration data, the necessary free-free frequencies and the associated modes for flexible bodies in multibody systems. In this paper, two different forms of constrained vibration data are considered. The first form is for structures supported by springs, and the second form is for structures supported by kinematic joints. The available vibration data may be either a complete set or an incomplete set.
{"title":"Identification of Free-Free Modes From Constrained Vibration Data for Flexible Multibody Models","authors":"T. Yi","doi":"10.1115/imece1998-0898","DOIUrl":"https://doi.org/10.1115/imece1998-0898","url":null,"abstract":"\u0000 This paper presents a method for identifying the free-free modes of an unconstrained structure by utilizing the available vibration data of the same constrained structure. In modal formulations for flexible body dynamics, modal data are primary known quantities that must be obtained either experimentally or analytically. For vibration measurements, the flexible body may be constrained differently than its actual conditions in the multibody system. To apply the experimentally obtained modal data to the flexible dynamic model, the available vibration data must be properly identified.\u0000 For a flexible body model in multibody systems, we may need a set of free-free modal data or constrained modal data depending upon the dynamic formulations. The identification of constrained modes from the free-free vibration data is straight forward, but the reverse process to determine the free-free modes from the constrained vibration data is difficult and expensive. The aim of this study is to extract, based on experimentally obtained vibration data, the necessary free-free frequencies and the associated modes for flexible bodies in multibody systems. In this paper, two different forms of constrained vibration data are considered. The first form is for structures supported by springs, and the second form is for structures supported by kinematic joints. The available vibration data may be either a complete set or an incomplete set.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131181017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research was on the effectiveness of stiffeners fastened on either side of a hole or cutout in a flat plate loaded in tension for reducing stress concentrations at the edge of the cutout. Stress data has been compiled from sixteen flat plate geometries having various hole diameter-to-plate width ratios. Each plate was modeled using an analysis software package and solved without stiffening, and then with stiffeners located at various distances from the hole. The reduction in the maximum stress in each plate geometry for stiffening at various distances from the hole was consistent. The stiffener positions closest to the hole always provided the greatest stiffening. The stress concentration in the plates was reduced 24%–41%. The largest reduction occurred in the plate with the largest hole diameter-to-plate width ratio. As the stiffeners moved farther from the hole, these reductions in the plate maximum stress dropped to as little as 11%. The number and location of the fasteners made a difference in the effectiveness of the stiffeners. Fasteners closest to the cutout were most instrumental in reducing the stress when the stiffeners were close to the hole.
{"title":"The Effect of Stiffening on the Stress Concentration in a Flat Plate With a Hole","authors":"M. Duchek, T. F. Lehnhoff","doi":"10.1115/imece1998-0895","DOIUrl":"https://doi.org/10.1115/imece1998-0895","url":null,"abstract":"\u0000 This research was on the effectiveness of stiffeners fastened on either side of a hole or cutout in a flat plate loaded in tension for reducing stress concentrations at the edge of the cutout. Stress data has been compiled from sixteen flat plate geometries having various hole diameter-to-plate width ratios. Each plate was modeled using an analysis software package and solved without stiffening, and then with stiffeners located at various distances from the hole.\u0000 The reduction in the maximum stress in each plate geometry for stiffening at various distances from the hole was consistent. The stiffener positions closest to the hole always provided the greatest stiffening. The stress concentration in the plates was reduced 24%–41%. The largest reduction occurred in the plate with the largest hole diameter-to-plate width ratio. As the stiffeners moved farther from the hole, these reductions in the plate maximum stress dropped to as little as 11%. The number and location of the fasteners made a difference in the effectiveness of the stiffeners. Fasteners closest to the cutout were most instrumental in reducing the stress when the stiffeners were close to the hole.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114736865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The macroscopically anisotropic homogenization of a multilayered media implicitly assumes that the spatial wavelength of material inhomogeneity is smaller than the macroscopic quantity of interest and hence, is a reasonable approximation of the bulk behavior. However, close to the crack tip, gradients in field quantities are strongly influenced by the local heterogeneity, which the isotropic or anisotropic homogenization fails to capture. The present work addresses the issues related to the influence of material inhomogeneity on local crack tip driving force. It is shown that to the first order, the effect of moduli inhomogeneity, residual stresses and inelastic strains on crack tip stress intensity factor are superposable. Detailed analytical model is developed for quantifying the effect of moduli inhomogeneity for the case of bimaterial multilayered media with functional interfaces, i.e., compositionally graded finite thickness interfaces. This method provides an efficient means to study thermoelastic crack problems in complex heterogeneous media, alleviating the numerical or analytical difficulties associated with the traditional methods. The results show that the material inhomogeneity plays a significant role in effecting the crack tip driving force.
{"title":"Crack in a Bimaterial Functionally Graded Multilayered Media","authors":"S. Muju","doi":"10.1115/imece1998-0882","DOIUrl":"https://doi.org/10.1115/imece1998-0882","url":null,"abstract":"\u0000 The macroscopically anisotropic homogenization of a multilayered media implicitly assumes that the spatial wavelength of material inhomogeneity is smaller than the macroscopic quantity of interest and hence, is a reasonable approximation of the bulk behavior. However, close to the crack tip, gradients in field quantities are strongly influenced by the local heterogeneity, which the isotropic or anisotropic homogenization fails to capture.\u0000 The present work addresses the issues related to the influence of material inhomogeneity on local crack tip driving force. It is shown that to the first order, the effect of moduli inhomogeneity, residual stresses and inelastic strains on crack tip stress intensity factor are superposable.\u0000 Detailed analytical model is developed for quantifying the effect of moduli inhomogeneity for the case of bimaterial multilayered media with functional interfaces, i.e., compositionally graded finite thickness interfaces.\u0000 This method provides an efficient means to study thermoelastic crack problems in complex heterogeneous media, alleviating the numerical or analytical difficulties associated with the traditional methods. The results show that the material inhomogeneity plays a significant role in effecting the crack tip driving force.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"418 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123006687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents implementation and application of automatic parametric design of 2D nonlinear FEA. Parametric design involves iterating on a FEA solver and preprocessor. Global quantities and linked database files provide the basis for analyzing the analyses. Parametric analysis of two disks contacting shows an expected relationship between interference, land height, and stress. Lastly, the assembly of press fit tubes shows the relationship between interference, contact area, and normal force.
{"title":"Implementation and Application of Automatic Parametric Design of 2D Nonlinear FEA","authors":"R. Verderber","doi":"10.1115/imece1998-0902","DOIUrl":"https://doi.org/10.1115/imece1998-0902","url":null,"abstract":"\u0000 This paper presents implementation and application of automatic parametric design of 2D nonlinear FEA. Parametric design involves iterating on a FEA solver and preprocessor. Global quantities and linked database files provide the basis for analyzing the analyses. Parametric analysis of two disks contacting shows an expected relationship between interference, land height, and stress. Lastly, the assembly of press fit tubes shows the relationship between interference, contact area, and normal force.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115825749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The response of a single-tendon tension leg platform subjected to stochastic wave and current loading is presented with a planar motion assumption. The tension leg platform will oscillate about its vertical position due to ocean waves. Current will cause a tension leg platform to oscillate about an offset position rather than its vertical position. This offset in the surge direction has a corresponding set down, the lowering of the hull in the heave direction, which increases the buoyancy forces. This results in a higher tension in the tendons than if the tendon and hull were in a vertical position. In prior papers the equations of motion and forcing functions were fully developed. The tendon and hull are both assumed to be cylindrical and therefore Morison’s equation was applied. In this paper, a Monte Carlo simulation was performed on the drag and inertia coefficients in Morison’s equation. A uniform random distribution of coefficients was selected from 0.6 to 2.0 for each coefficient. Twenty computer simulations were implemented for each coefficient. The response showed that the offset position and the amplitude are both dependent on the drag coefficient. The surge of the hull shows a maximum offset approximately three times greater for the coefficient that resulted in the maximum displacement than the minimum. The response did not show a significant dependence on the inertia co-efficient, however, this is not necessarily true for unsteady current, large hull and tendon diameters, ocean wave frequencies greater than 1 radian/second, and low current velocity.
{"title":"Monte Carlo Simulation of a Partially Submerged Compliant Structure","authors":"R. Adrezin, H. Benaroya","doi":"10.1115/imece1998-0900","DOIUrl":"https://doi.org/10.1115/imece1998-0900","url":null,"abstract":"\u0000 The response of a single-tendon tension leg platform subjected to stochastic wave and current loading is presented with a planar motion assumption. The tension leg platform will oscillate about its vertical position due to ocean waves. Current will cause a tension leg platform to oscillate about an offset position rather than its vertical position. This offset in the surge direction has a corresponding set down, the lowering of the hull in the heave direction, which increases the buoyancy forces. This results in a higher tension in the tendons than if the tendon and hull were in a vertical position. In prior papers the equations of motion and forcing functions were fully developed. The tendon and hull are both assumed to be cylindrical and therefore Morison’s equation was applied. In this paper, a Monte Carlo simulation was performed on the drag and inertia coefficients in Morison’s equation. A uniform random distribution of coefficients was selected from 0.6 to 2.0 for each coefficient. Twenty computer simulations were implemented for each coefficient. The response showed that the offset position and the amplitude are both dependent on the drag coefficient. The surge of the hull shows a maximum offset approximately three times greater for the coefficient that resulted in the maximum displacement than the minimum. The response did not show a significant dependence on the inertia co-efficient, however, this is not necessarily true for unsteady current, large hull and tendon diameters, ocean wave frequencies greater than 1 radian/second, and low current velocity.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124923140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The primary objective of this investigation was to determine the effect on the mechanical and fatigue properties induced by sintering powder on Ti-6wt.%Al-4wt.%V ELI (Extra Low Interstitial) alloy substrates as compared to annealing, and overheating thermal treatments. Fatigue tests were conducted using a variable speed plate fatigue machine on various specimens in the different thermally-treated conditions so that a comparison study of the fatigue characteristics could be performed. The heat treatments, which included as-annealed, as-overheated, and sintered porous-coated, were performed on the plate fatigue specimens prior to testing in the variable speed fatigue plate machine. A comparison study of the fatigue results/properties of the samples subjected to the three thermal treatments revealed that the annealed specimens exhibited superior fatigue resistance as compared to the as-overheated and porous-coated samples. However, a substantial decrease in the fatigue resistance of the porous coated sintered to the as-overheated thermal treatment was not evidenced. It was determined that the decrease in the fatigue resistance of the as-overheated, as compared to the annealed heat treatment, was a result of an increase in the macroscopic grain size. Furthermore, for the porous-coated specimens, it was determined that the presence of stress concentrations at the surface irregularities of the sintered bond sites resulted in the decrease fatigue resistance. It was found, from optical metallography on the sintered porous-coated samples, that microscopic fatigue cracks originated at the necked regions of both the particle-substrate interface and the particle-particle interface. From these findings it was determined that the fatigue cracks at the particle-substrate interface contributed to the ultimate fatigue failure of the sintered porous-coated plate fatigue specimens.
{"title":"The Effect of Annealing, Overheating, and a Sintered Porous Coating Thermal Treatments on the Fatigue Properties of Ti-6.0wt.%Al-4.0wt.%V ELI Alloy Plate Specimens","authors":"J. Fragomeni","doi":"10.1115/imece1998-0906","DOIUrl":"https://doi.org/10.1115/imece1998-0906","url":null,"abstract":"\u0000 The primary objective of this investigation was to determine the effect on the mechanical and fatigue properties induced by sintering powder on Ti-6wt.%Al-4wt.%V ELI (Extra Low Interstitial) alloy substrates as compared to annealing, and overheating thermal treatments. Fatigue tests were conducted using a variable speed plate fatigue machine on various specimens in the different thermally-treated conditions so that a comparison study of the fatigue characteristics could be performed. The heat treatments, which included as-annealed, as-overheated, and sintered porous-coated, were performed on the plate fatigue specimens prior to testing in the variable speed fatigue plate machine. A comparison study of the fatigue results/properties of the samples subjected to the three thermal treatments revealed that the annealed specimens exhibited superior fatigue resistance as compared to the as-overheated and porous-coated samples. However, a substantial decrease in the fatigue resistance of the porous coated sintered to the as-overheated thermal treatment was not evidenced. It was determined that the decrease in the fatigue resistance of the as-overheated, as compared to the annealed heat treatment, was a result of an increase in the macroscopic grain size. Furthermore, for the porous-coated specimens, it was determined that the presence of stress concentrations at the surface irregularities of the sintered bond sites resulted in the decrease fatigue resistance. It was found, from optical metallography on the sintered porous-coated samples, that microscopic fatigue cracks originated at the necked regions of both the particle-substrate interface and the particle-particle interface. From these findings it was determined that the fatigue cracks at the particle-substrate interface contributed to the ultimate fatigue failure of the sintered porous-coated plate fatigue specimens.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123861259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The goal of this study was to conduct a qualitative analysis to determine the effectiveness of countermine boots. This was done by determining their ability to dissipate a blast force equivalent to a typical anti-personnel landmine. This was followed by a parametric study that which involved altering the component materials in an effort to determine if the effectiveness of the boots varied as the materials changed. A finite element analysis was conducted to evaluate the effectiveness of the countermine boot based upon accepted tolerance levels of the lower extremity of the body. The materials and their dimensions were modified in the finite element model to determine how these modifications would impact the boots’ effectiveness.
{"title":"Study of Effectiveness of Countermine Boots","authors":"Y. Kwon, Richard C. Muschek","doi":"10.1115/imece1998-0887","DOIUrl":"https://doi.org/10.1115/imece1998-0887","url":null,"abstract":"\u0000 The goal of this study was to conduct a qualitative analysis to determine the effectiveness of countermine boots. This was done by determining their ability to dissipate a blast force equivalent to a typical anti-personnel landmine. This was followed by a parametric study that which involved altering the component materials in an effort to determine if the effectiveness of the boots varied as the materials changed. A finite element analysis was conducted to evaluate the effectiveness of the countermine boot based upon accepted tolerance levels of the lower extremity of the body. The materials and their dimensions were modified in the finite element model to determine how these modifications would impact the boots’ effectiveness.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127219788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Technology has improved dramatically over the last quarter century. It has allowed the development of personal body armor capable of preventing penetration of fragments traveling in excess of 609 m/s (2000 ft/s). However, these strides have also exposed the body to greater impact energies without a lethal penetration. The objective of this study was to examine how the body, in particular the head-neck complex, responds to these impacts. A finite element model was developed to characterize the behavior of this biomechanical system. This model was validated against experimental work. The validated model was then subjected to impacts at different positions to induce different load cases. Each set of results was then compared to Head Injury Criteria (HIC), Abbreviated Injury Scale (AIS), and the Injury Assessment Reference Values (IARVS) for evidence of injury potential. Disc stiffness was found to be proportional to the injury potential. Rupture of the disc was considered likely for most cases considered. Fracture of the vertebral body was considered likely in a half of the cases under study.
{"title":"Biomechaimical Study of Ballistic Impact on Helmets: Injury of Head and Neck","authors":"Y. W. Kwon, Q. M. King","doi":"10.1115/imece1998-0886","DOIUrl":"https://doi.org/10.1115/imece1998-0886","url":null,"abstract":"\u0000 Technology has improved dramatically over the last quarter century. It has allowed the development of personal body armor capable of preventing penetration of fragments traveling in excess of 609 m/s (2000 ft/s). However, these strides have also exposed the body to greater impact energies without a lethal penetration. The objective of this study was to examine how the body, in particular the head-neck complex, responds to these impacts. A finite element model was developed to characterize the behavior of this biomechanical system. This model was validated against experimental work. The validated model was then subjected to impacts at different positions to induce different load cases. Each set of results was then compared to Head Injury Criteria (HIC), Abbreviated Injury Scale (AIS), and the Injury Assessment Reference Values (IARVS) for evidence of injury potential. Disc stiffness was found to be proportional to the injury potential. Rupture of the disc was considered likely for most cases considered. Fracture of the vertebral body was considered likely in a half of the cases under study.","PeriodicalId":270413,"journal":{"name":"Recent Advances in Solids and Structures","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126671376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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