Peridynamics formulation provides a strong tool for modeling of crack propagation. Although its ability to handle crack propagation is impressive it suffers from the drawback of high computational cost. In order to reduce the computational cost, peridynamics can be coupled with the finite element method. In this approach, peridynamics is used in critical areas where crack growth can happen and finite element formulation is used everywhere else. We use an Arlequin based coupling method to couple both peridynamics and finite element domain and implement the coupling approach in an existing finite element package. Initially, the user meshes the whole domain using finite elements. The software converts finite element mesh in the critical areas into peridynamics points. The proposed approach automatically creates a seamless coupling between the two regions. An example of a bar hitting a fixed plate is solved and compared with pure finite element results to prove the robustness of the method. Also, a problem of crack propagation under mixed mode loading is solved.
{"title":"Seamless Coupling of Peridynamics and Finite Element Method in Commercial Software of Finite Element to Solve Elasto-Dynamics Problems","authors":"Xiaonan Wang, S. Kulkarni, A. Tabarraei","doi":"10.1115/imece2019-10136","DOIUrl":"https://doi.org/10.1115/imece2019-10136","url":null,"abstract":"\u0000 Peridynamics formulation provides a strong tool for modeling of crack propagation. Although its ability to handle crack propagation is impressive it suffers from the drawback of high computational cost. In order to reduce the computational cost, peridynamics can be coupled with the finite element method. In this approach, peridynamics is used in critical areas where crack growth can happen and finite element formulation is used everywhere else. We use an Arlequin based coupling method to couple both peridynamics and finite element domain and implement the coupling approach in an existing finite element package. Initially, the user meshes the whole domain using finite elements. The software converts finite element mesh in the critical areas into peridynamics points. The proposed approach automatically creates a seamless coupling between the two regions. An example of a bar hitting a fixed plate is solved and compared with pure finite element results to prove the robustness of the method. Also, a problem of crack propagation under mixed mode loading is solved.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125376061","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}
A series of uniaxial and oblique flyer-plate impact experiments were conducted on fully dense, high durometer, polyurethane and epoxy formulations to investigate the high strain-rate dynamic material response. Samples were impacted at velocities ranging from 50 to 1,200 m/s at strain-rates of 105 – 106 s−1. The Hugoniot constants, yield strengths, and friction coefficients were inferred from velocity measurements taken from the back surface of the targets. Polymer Hugoniots were found to closely approximate those previously found in literature, with nonlinear curvature at low impact speeds due to viscoelastic effects. Strength behavior demonstrated pressure dependence which fit into a Mohr-Coulomb or Drucker-Prager yield surface criterion. Coefficients of friction between both epoxy and polyurethane, alongside a 7075-T6 aluminum tribological partner were quantified and results were used in conjunction with yield observations to hypothesize on the role of adhesion in high strain-rate shear of polymer-metal interfaces.
{"title":"Mechanical Behavior of Thermosetting Polymers Undergoing High Strain-Rate Impact","authors":"P. Sable, J. Borg","doi":"10.1115/imece2019-10459","DOIUrl":"https://doi.org/10.1115/imece2019-10459","url":null,"abstract":"\u0000 A series of uniaxial and oblique flyer-plate impact experiments were conducted on fully dense, high durometer, polyurethane and epoxy formulations to investigate the high strain-rate dynamic material response. Samples were impacted at velocities ranging from 50 to 1,200 m/s at strain-rates of 105 – 106 s−1. The Hugoniot constants, yield strengths, and friction coefficients were inferred from velocity measurements taken from the back surface of the targets. Polymer Hugoniots were found to closely approximate those previously found in literature, with nonlinear curvature at low impact speeds due to viscoelastic effects. Strength behavior demonstrated pressure dependence which fit into a Mohr-Coulomb or Drucker-Prager yield surface criterion. Coefficients of friction between both epoxy and polyurethane, alongside a 7075-T6 aluminum tribological partner were quantified and results were used in conjunction with yield observations to hypothesize on the role of adhesion in high strain-rate shear of polymer-metal interfaces.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"1125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116077831","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 fantastic properties of polyurea such as flexibility, durability, and chemical resistance have brought it a wide range of application in various industries. Effective prediction of the response of polyurea under different loading and environmental conditions necessitates the development of an accurate constitutive model. Similar to most polymers, the behavior of polyurea depends on both the strain and strain rate. Therefore, the constitutive model should be able to capture both these effects on the response of polyurea. To achieve this objective, in this paper, a nonlinear visco-hyper elastic constitutive model is developed by the superposition of a hyperelastic and a viscoelastic model. The proposed constitutive model can capture the behavior of polyurea under compressive as well as tensile loading conditions at various strain rates. Four parameter Ogden model is used to model the hyperelastic behavior of polyurea. The viscoelastic behavior is modeled using a three-parameter standard linear solid (SLS) model. The material parameters of the model are found by curve fitting of the proposed model to the experimental data. Comparison of the proposed model and the experimental data shows that the proposed model can closely reproduce the stress-strain behavior of polyurea under a wide range of strain rates (−6500 to 294 /s).
{"title":"A Nonlinear Visco-Hyper Elastic Constitutive Model for Modeling Behavior of Polyurea at Large Deformations","authors":"S. Kulkarni, A. Tabarraei","doi":"10.1115/imece2019-10071","DOIUrl":"https://doi.org/10.1115/imece2019-10071","url":null,"abstract":"\u0000 The fantastic properties of polyurea such as flexibility, durability, and chemical resistance have brought it a wide range of application in various industries. Effective prediction of the response of polyurea under different loading and environmental conditions necessitates the development of an accurate constitutive model. Similar to most polymers, the behavior of polyurea depends on both the strain and strain rate. Therefore, the constitutive model should be able to capture both these effects on the response of polyurea. To achieve this objective, in this paper, a nonlinear visco-hyper elastic constitutive model is developed by the superposition of a hyperelastic and a viscoelastic model. The proposed constitutive model can capture the behavior of polyurea under compressive as well as tensile loading conditions at various strain rates. Four parameter Ogden model is used to model the hyperelastic behavior of polyurea. The viscoelastic behavior is modeled using a three-parameter standard linear solid (SLS) model. The material parameters of the model are found by curve fitting of the proposed model to the experimental data. Comparison of the proposed model and the experimental data shows that the proposed model can closely reproduce the stress-strain behavior of polyurea under a wide range of strain rates (−6500 to 294 /s).","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130510349","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}
Carl Moore, M. Pollard, Tarik J. Dickens, Hui Wang
We are investigating the impact on 3D printed part strength when the extruder is positioned using articulated robotic arms in place of a traditional x-y gantry-style system. One of our printer designs is called the DeXter printer [1] which uses two selective compliance assembly robotic arms (SCARA) to position dual extruders. An advantage of using dual robotic arms is that two extruders can move independently drastically reducing build times, or the second arm can perform additional operations like segment stimulation during the build process [2]. In either case the arms require a collision avoidance process to prevent them from colliding in the part space. A possible drawback of the collision avoidance requirement is that it can result in a time delay along some sections of the layer which, due to cooling, could have adverse effects on the part strength. This research aims to determine how this cooling time will affect the strength of ABS extruded parts. We performed tensile tests on 3D printed part samples for which we altered the g-code to produce a variable time delay during the printing process. Our control sample had a zero-dwell time, and as we increased dwell time we found that the ultimate tensile strength (UTS) did decrease.
{"title":"The Effect of Time Delay on 3D Printed Part Strength","authors":"Carl Moore, M. Pollard, Tarik J. Dickens, Hui Wang","doi":"10.1115/imece2019-11790","DOIUrl":"https://doi.org/10.1115/imece2019-11790","url":null,"abstract":"\u0000 We are investigating the impact on 3D printed part strength when the extruder is positioned using articulated robotic arms in place of a traditional x-y gantry-style system. One of our printer designs is called the DeXter printer [1] which uses two selective compliance assembly robotic arms (SCARA) to position dual extruders. An advantage of using dual robotic arms is that two extruders can move independently drastically reducing build times, or the second arm can perform additional operations like segment stimulation during the build process [2]. In either case the arms require a collision avoidance process to prevent them from colliding in the part space. A possible drawback of the collision avoidance requirement is that it can result in a time delay along some sections of the layer which, due to cooling, could have adverse effects on the part strength. This research aims to determine how this cooling time will affect the strength of ABS extruded parts.\u0000 We performed tensile tests on 3D printed part samples for which we altered the g-code to produce a variable time delay during the printing process. Our control sample had a zero-dwell time, and as we increased dwell time we found that the ultimate tensile strength (UTS) did decrease.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"228 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131357057","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 present study focuses on the aerodynamic performance and structural analysis of the centrifugal compressor impeller. Performance characteristics of the impeller are analyzed with and without splitter blades by varying the total number of main and splitter blades. The operating conditions of the compressor under centrifugal force and pressure load from the aerodynamic analysis were applied to the impeller blade and hub to perform the one-way Fluid-Structure Interaction (FSI). For the stress assessment, maximum equivalent von-Mises stresses in the impeller blades are compared with the maximum allowable stress of the impeller material. The effects of varying pressure field on the deformation and stress of the impeller is also calculated. The aerodynamic and structural performance of the centrifugal compressor at 73000 rpm are investigated in terms of the efficiency, pressure ratio, equivalent von-Mises stress, and total deformation of the impeller.
{"title":"Performance Analysis of the Impeller of a Centrifugal Air Compressor","authors":"T. R. Jebieshia, S. Raman, H. Kim","doi":"10.1115/imece2019-11123","DOIUrl":"https://doi.org/10.1115/imece2019-11123","url":null,"abstract":"\u0000 The present study focuses on the aerodynamic performance and structural analysis of the centrifugal compressor impeller. Performance characteristics of the impeller are analyzed with and without splitter blades by varying the total number of main and splitter blades. The operating conditions of the compressor under centrifugal force and pressure load from the aerodynamic analysis were applied to the impeller blade and hub to perform the one-way Fluid-Structure Interaction (FSI). For the stress assessment, maximum equivalent von-Mises stresses in the impeller blades are compared with the maximum allowable stress of the impeller material. The effects of varying pressure field on the deformation and stress of the impeller is also calculated. The aerodynamic and structural performance of the centrifugal compressor at 73000 rpm are investigated in terms of the efficiency, pressure ratio, equivalent von-Mises stress, and total deformation of the impeller.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131371163","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}
Analytical solutions of thin film dampers are useful for determining critical speeds and stability of rotor systems. Most thin film dampers in use are of short axial length, and closed-form solutions to the Reynolds equations exist for estimating pressure, forces, and damping for these types of dampers. This article compares the fluid film forces and damping estimated by the short film bearing model form of the Reynolds equations to the calculated forces and damping of a transient computational fluid dynamic simulation. For this comparison, the fluid was assumed to be incompressible, laminar, and isoviscous. The fluid film forces and damping are calculated from integrating the pressure distribution over the surface of the damper due to small amplitude motions about a steady state static off-center circular orbit. In this case, no cavitation is assumed, and the journal has no angular velocity, so direct stiffness cannot be calculated from the closed-form solution. Radial clearance, journal length, and journal eccentricity have a significant effect on fluid force and damping within a thin film damper. Fluid density does not affect fluid force or damping substantially, while fluid viscosity does. Both the closed-form solutions and computational fluid dynamics simulation compare well with each other and reflect these trends.
{"title":"Estimated Fluid Force and Damping Characteristics of a Thin Film Damper Comparison Between Closed-Form Solutions and Numerical Analysis","authors":"J. Cook","doi":"10.1115/imece2019-10171","DOIUrl":"https://doi.org/10.1115/imece2019-10171","url":null,"abstract":"\u0000 Analytical solutions of thin film dampers are useful for determining critical speeds and stability of rotor systems. Most thin film dampers in use are of short axial length, and closed-form solutions to the Reynolds equations exist for estimating pressure, forces, and damping for these types of dampers. This article compares the fluid film forces and damping estimated by the short film bearing model form of the Reynolds equations to the calculated forces and damping of a transient computational fluid dynamic simulation. For this comparison, the fluid was assumed to be incompressible, laminar, and isoviscous. The fluid film forces and damping are calculated from integrating the pressure distribution over the surface of the damper due to small amplitude motions about a steady state static off-center circular orbit. In this case, no cavitation is assumed, and the journal has no angular velocity, so direct stiffness cannot be calculated from the closed-form solution. Radial clearance, journal length, and journal eccentricity have a significant effect on fluid force and damping within a thin film damper. Fluid density does not affect fluid force or damping substantially, while fluid viscosity does. Both the closed-form solutions and computational fluid dynamics simulation compare well with each other and reflect these trends.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134045485","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}
In many types of spacecraft and missile systems, the vehicle’s skin cutting are carried out by using the mild-detonating fuse (MDF) or the flexible linear shaped charge (FLSC). MDF is a very thin metal tube that filled with explosive charges and has an axisymmetric shape. FLSC is an inverted chevron-shaped flexible tube that generates hypervelocity jet to penetrate or cut thick metal structures. In this study, the characteristics of MDF and FLSC for metal plate cutting are identified. First, the fracture mechanisms due to MDF and FLSC are numerically analyzed in 2-D plane strain using ANSYS AUTODYN, one of commercial hydrocodes. By using proposed numerical scheme, the effects of the cutting methods and the design parameters on cutting performance, fragmentation and backward shock waves are studied; the pros and cons of MDF and FLSC for metal plate cutting are clarified. The numerical method and the results of this study provide the guidelines to select metal plate cutting method and help to establish the design method for optimal metal plate cutting; the number of the expensive explosive experiments can be reduced.
{"title":"Characteristics Study of Mild-Detonating Fuse and Flexible Linear Shaped Charge for Metal Plate Cutting","authors":"Juho Lee, J. Lee, Heon-Joo Lee, Youn-Do Kang","doi":"10.1115/imece2019-11110","DOIUrl":"https://doi.org/10.1115/imece2019-11110","url":null,"abstract":"\u0000 In many types of spacecraft and missile systems, the vehicle’s skin cutting are carried out by using the mild-detonating fuse (MDF) or the flexible linear shaped charge (FLSC). MDF is a very thin metal tube that filled with explosive charges and has an axisymmetric shape. FLSC is an inverted chevron-shaped flexible tube that generates hypervelocity jet to penetrate or cut thick metal structures. In this study, the characteristics of MDF and FLSC for metal plate cutting are identified. First, the fracture mechanisms due to MDF and FLSC are numerically analyzed in 2-D plane strain using ANSYS AUTODYN, one of commercial hydrocodes. By using proposed numerical scheme, the effects of the cutting methods and the design parameters on cutting performance, fragmentation and backward shock waves are studied; the pros and cons of MDF and FLSC for metal plate cutting are clarified. The numerical method and the results of this study provide the guidelines to select metal plate cutting method and help to establish the design method for optimal metal plate cutting; the number of the expensive explosive experiments can be reduced.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"55 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116019695","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 recently synthesized two–dimensional C3N is a graphene–like two–dimensional material with remarkable electronic, optoelectronic, thermal, mechanical and chemical properties. Molecular dynamics (MD) simulation is used to investigate the fracture properties of C3N. Cracks with different geometry and orientations are used to investigate how the crack tip configuration and orientation impact the fracture properties of C3N. The results show that regardless of their initial orientation, at microscale cracks always tend to propagate along a zigzag direction. The MD results are used to estimate the critical energy release rate of C3N. The critical energy release rate of both armchair and zigzag cracks increases with the decrease of crack length when the crack length is less than 7 nm. The critical energy release rate for armchair and zigzag cracks longer than 7 nm is respectively 10.16 J/m2 and 8.52 J/m2 which are significantly lower than those of graphene.
{"title":"A Molecular Dynamic Study of Nano-Fracture of C3N","authors":"Imrul Reza Shishir, A. Tabarraei","doi":"10.1115/imece2019-11543","DOIUrl":"https://doi.org/10.1115/imece2019-11543","url":null,"abstract":"\u0000 The recently synthesized two–dimensional C3N is a graphene–like two–dimensional material with remarkable electronic, optoelectronic, thermal, mechanical and chemical properties. Molecular dynamics (MD) simulation is used to investigate the fracture properties of C3N. Cracks with different geometry and orientations are used to investigate how the crack tip configuration and orientation impact the fracture properties of C3N. The results show that regardless of their initial orientation, at microscale cracks always tend to propagate along a zigzag direction. The MD results are used to estimate the critical energy release rate of C3N. The critical energy release rate of both armchair and zigzag cracks increases with the decrease of crack length when the crack length is less than 7 nm. The critical energy release rate for armchair and zigzag cracks longer than 7 nm is respectively 10.16 J/m2 and 8.52 J/m2 which are significantly lower than those of graphene.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126053394","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}
Structural discontinuities, such as voids or inclusions in otherwise uniform, solid materials have previously been successfully implemented to alter the propagation of various types of waves through a range of materials and structures. Much of this work has focused on micro-scale features and low energy waves. The disruption of waves carrying larger amounts of energy currently relies mainly on large material deformation, typically with a layer of the structure becoming permanently damaged in order to protect other portions. However, the ability to disrupt, alter, direct, and control higher energy waves without significant damage to the material or structure can be desirable. Microscale features can disperse wave fronts, scattering their energy and reducing the potentially damaging effects of the concentrated loads carried in these waves. However, the control of the distribution of these microscale features throughout the material and structure can be difficult, limiting the ability to use these materials to control the dispersion of the wave energy or direct it to more desirable regions in the structure. Macro-scale features can be more easily formed into patterns and arrangements which can be designed for specific wave-controlling or directing properties. Additionally, materials and structures with macro-scale discontinuities can result in a greater change in energy per inclusion and a greater spatial range of their effects throughout the domain of the material. Therefore, they have the potential to be used to address input waves of higher energy. The use of macro-scale features may provide added manufacturing-based benefits, particularly with the more widespread development and use of advanced manufacturing methods, such as additive manufacturing. This study examines the feasibility of the use of arrays of macro-scale features to direct and control input stress waves. The effect of the shape and arrangement of macro-scale geometric features is studied under a range of orders of magnitudes of the incident stress wave. Methods are developed in this work to predict the propagation of the stress waves through the material and to quantitatively assess the effects of these included arrays of structural, geometric discontinuities. The results of this study are used to evaluate the feasibility of the use of these geometric macro-scale arrays to control the propagation of stress waves in structures while limiting gross material deformation and damage to the overall structure.
{"title":"Macro-Scale Geometric Voids to Alter Stress Wave Propagation in Solids","authors":"C. S. Florio","doi":"10.1115/imece2019-10765","DOIUrl":"https://doi.org/10.1115/imece2019-10765","url":null,"abstract":"\u0000 Structural discontinuities, such as voids or inclusions in otherwise uniform, solid materials have previously been successfully implemented to alter the propagation of various types of waves through a range of materials and structures. Much of this work has focused on micro-scale features and low energy waves. The disruption of waves carrying larger amounts of energy currently relies mainly on large material deformation, typically with a layer of the structure becoming permanently damaged in order to protect other portions. However, the ability to disrupt, alter, direct, and control higher energy waves without significant damage to the material or structure can be desirable.\u0000 Microscale features can disperse wave fronts, scattering their energy and reducing the potentially damaging effects of the concentrated loads carried in these waves. However, the control of the distribution of these microscale features throughout the material and structure can be difficult, limiting the ability to use these materials to control the dispersion of the wave energy or direct it to more desirable regions in the structure. Macro-scale features can be more easily formed into patterns and arrangements which can be designed for specific wave-controlling or directing properties. Additionally, materials and structures with macro-scale discontinuities can result in a greater change in energy per inclusion and a greater spatial range of their effects throughout the domain of the material. Therefore, they have the potential to be used to address input waves of higher energy. The use of macro-scale features may provide added manufacturing-based benefits, particularly with the more widespread development and use of advanced manufacturing methods, such as additive manufacturing.\u0000 This study examines the feasibility of the use of arrays of macro-scale features to direct and control input stress waves. The effect of the shape and arrangement of macro-scale geometric features is studied under a range of orders of magnitudes of the incident stress wave. Methods are developed in this work to predict the propagation of the stress waves through the material and to quantitatively assess the effects of these included arrays of structural, geometric discontinuities. The results of this study are used to evaluate the feasibility of the use of these geometric macro-scale arrays to control the propagation of stress waves in structures while limiting gross material deformation and damage to the overall structure.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114252919","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}
Present day demands composite material with even lighter weight and higher strength for using in aerospace, automobile and defense industries. Due to posing significantly weight saving and higher stiffness attribute, use of sandwich composite structure is the demand of the time. Impact analysis of sandwich composite armor system is necessary to design and develop new armor for defense sectors. The goal of this study is to design, model and analyze the dynamic response of the composite armor system in terms of residual velocity and energy absorption capacity. The design parameters are investigated for different fiber reinforced polymers (High tensile strength Carbon/epoxy, Carbon Fiber/Carbon Nanotube reinforced polymers) as top and bottom skin, with an Aluminum Alloy 7039 corrugated core structure and square prismoid assembled Ceramic (SiC) core centerpieces at different velocities (50 m/s, 100 m/s, 200 m/s, 400 m/s). This non-linear explicit dynamic study is performed using commercial software ABAQUS CAE 2017. Best combination for the composite armor system is suggested based on the results.
{"title":"Impact Analysis of a Composite Armor System","authors":"S. Alam, M. Saquib","doi":"10.1115/imece2019-11748","DOIUrl":"https://doi.org/10.1115/imece2019-11748","url":null,"abstract":"\u0000 Present day demands composite material with even lighter weight and higher strength for using in aerospace, automobile and defense industries. Due to posing significantly weight saving and higher stiffness attribute, use of sandwich composite structure is the demand of the time. Impact analysis of sandwich composite armor system is necessary to design and develop new armor for defense sectors.\u0000 The goal of this study is to design, model and analyze the dynamic response of the composite armor system in terms of residual velocity and energy absorption capacity.\u0000 The design parameters are investigated for different fiber reinforced polymers (High tensile strength Carbon/epoxy, Carbon Fiber/Carbon Nanotube reinforced polymers) as top and bottom skin, with an Aluminum Alloy 7039 corrugated core structure and square prismoid assembled Ceramic (SiC) core centerpieces at different velocities (50 m/s, 100 m/s, 200 m/s, 400 m/s).\u0000 This non-linear explicit dynamic study is performed using commercial software ABAQUS CAE 2017. Best combination for the composite armor system is suggested based on the results.","PeriodicalId":375383,"journal":{"name":"Volume 9: Mechanics of Solids, Structures, and Fluids","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127718617","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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