Ceramics are extensively used in protective structures which are often subjected to projectile impacts.During an impact process of a ceramic target by a projectile,fragmentation occurs in both the target and the proje...Ceramics are extensively used in protective structures which are often subjected to projectile impacts.During an impact process of a ceramic target by a projectile,fragmentation occurs in both the target and the projectile.It is challenging to simulate such events and predict residual mass and velocity of the projectile.In this work,we attempt to use smoothed particle hydrodynamics(SPH)in LS-DYNA to reproduce fragmentation of the target and the projectile and predict residual mass and velocity of the projectile during a projectile impact of a ceramic target.SPH models for an alumina ceramic tile impacted by a blunt tungsten heavy alloy projectile are established.SPH simulation results of residual mass and velocity of the projectile as well as ejecta and bulge movements of the ceramic tile are obtained and compared with experimental data and simulation results of other numerical approaches.It is found that SPH simulation can properly reproduce the impact fragmentation of the target and the projectile,and shows advantages over existing numerical approaches in the prediction accuracy of residual mass and velocity.Moreover,effects of some numerical aspects of SPH,including particle spacing,contact treatment and parameters in artificial viscosity and smoothing length,on simulation results are identified.A simple approach using identical smoothing length and balanced artificial viscosity is proposed to reduce particle spacing sensitivity.The observed parametric effects and the proposed approach will provide guidance to set appropriate parameters values for SPH simulation of impact fragmentation.展开更多
Recently,we developed a nonbuckling interconnect design that provides an effective approach to simultaneously achieving high elastic stretchability,easiness for encapsulation,and high electric performance for stretcha...Recently,we developed a nonbuckling interconnect design that provides an effective approach to simultaneously achieving high elastic stretchability,easiness for encapsulation,and high electric performance for stretchable electronics.This paper aims to systematically study its mechanical and electric behaviors,including comparisons of the nonbuckling and buckling interconnect designs on stretchability,effects of the thickness on electric performance,and modeling and experimental investigations on the finite deformation mechanics.It is found that the results on stretchability depend on the layouts.Long straight segments and small arc radii for nonbuckling interconnects yield an enhancement of stretchability,which is much better than that of buckling designs.On the other hand,shorter straight segments or thicker interconnects are better to lower the resistances of interconnects.Therefore,optimization of the designs needs to balance the requirements of both the mechanical and electric performances.The finite deformation of interconnects during stretching is analyzed.The established analytic model is well validated by both the finite element modeling and experimental investigations.This work is key for providing the design guidelines for nonbucklingbased stretchable electronics.展开更多
基金National Natural Science Foundation of China(Grant No.11862005)Natural Science Foundation of Jiangxi Province of China(Grant No.20181BAB211012)Tianjin Natural Science Foundation of China(Grant No.18JCYBJC88500)is gratefully acknowledged.
文摘Ceramics are extensively used in protective structures which are often subjected to projectile impacts.During an impact process of a ceramic target by a projectile,fragmentation occurs in both the target and the projectile.It is challenging to simulate such events and predict residual mass and velocity of the projectile.In this work,we attempt to use smoothed particle hydrodynamics(SPH)in LS-DYNA to reproduce fragmentation of the target and the projectile and predict residual mass and velocity of the projectile during a projectile impact of a ceramic target.SPH models for an alumina ceramic tile impacted by a blunt tungsten heavy alloy projectile are established.SPH simulation results of residual mass and velocity of the projectile as well as ejecta and bulge movements of the ceramic tile are obtained and compared with experimental data and simulation results of other numerical approaches.It is found that SPH simulation can properly reproduce the impact fragmentation of the target and the projectile,and shows advantages over existing numerical approaches in the prediction accuracy of residual mass and velocity.Moreover,effects of some numerical aspects of SPH,including particle spacing,contact treatment and parameters in artificial viscosity and smoothing length,on simulation results are identified.A simple approach using identical smoothing length and balanced artificial viscosity is proposed to reduce particle spacing sensitivity.The observed parametric effects and the proposed approach will provide guidance to set appropriate parameters values for SPH simulation of impact fragmentation.
基金supported by the National Natural Science Foundation of China(Grant Nos.11572323,11772331,11302038,51365013,and 11732004)the Chinese Academy of Sciences via the"Hundred Talent Program"+8 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB22040501)the State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology(Grant No.GZ1603)the State Key Laboratory of Digital Manufacturing Equipment and Technology,Huazhong University of Science and Technology(Grant No.DMETKF2017008)the Young Elite Scientists Sponsorship Program by CAST(Grant No.2015QNRC001)the Opening Fund of State Key Laboratory of Nonlinear Mechanicsthe Personnel Training Plan of Tianjin City in China for the Key Young and Middle-Aged Innovation Talentsthe National Key Research and Development Plan(Grant Nos.2016YFB0201600,2016YFB0201601,2017YFB0202800,and 2017YFB0202802)the Program for Changjiang Scholars,Innovative Research Team in University(PCSIRT)the 111 Project(Grant No.B14013)
文摘Recently,we developed a nonbuckling interconnect design that provides an effective approach to simultaneously achieving high elastic stretchability,easiness for encapsulation,and high electric performance for stretchable electronics.This paper aims to systematically study its mechanical and electric behaviors,including comparisons of the nonbuckling and buckling interconnect designs on stretchability,effects of the thickness on electric performance,and modeling and experimental investigations on the finite deformation mechanics.It is found that the results on stretchability depend on the layouts.Long straight segments and small arc radii for nonbuckling interconnects yield an enhancement of stretchability,which is much better than that of buckling designs.On the other hand,shorter straight segments or thicker interconnects are better to lower the resistances of interconnects.Therefore,optimization of the designs needs to balance the requirements of both the mechanical and electric performances.The finite deformation of interconnects during stretching is analyzed.The established analytic model is well validated by both the finite element modeling and experimental investigations.This work is key for providing the design guidelines for nonbucklingbased stretchable electronics.
