This study presents a significant advancement in the vibration analysis of functionally graded sandwich plates with auxetic cores by introducing a general viscoelastic foundation model that more accurately reflects th...This study presents a significant advancement in the vibration analysis of functionally graded sandwich plates with auxetic cores by introducing a general viscoelastic foundation model that more accurately reflects the complex interactions between the plate and the foundation.The novelty of this study is that the proposed viscoelastic foundation model incorporates elastic and damping effects in both the Winkler and Pasternak layers.To develop the theoretical framework for this analysis,the higher-order shear deformation theory is employed,while Hamilton's principle is used to derive the governing equations of motion.The closed-form solution is used to determine the damped vibration behaviors of the sandwich plates.The precision and robustness of the proposed mathematical model are validated through several comparison studies with existing numerical results.A detailed parametric study is conducted to investigate the influence of various parameters,including the elastic and damping coefficients of the foundation,the material gradation,and the properties of the auxetic core on the vibration behavior of the plates.The numerical results provide new insights into the vibration characteristics of sandwich plates with auxetic cores resting on viscoelastic foundation,highlighting the significant role of the two damping coefficients and auxetic cores in the visco-vibration behavior of the plates.展开更多
This study focusses on establishing the finite element model based on a new hyperbolic sheareformation theory to investigate the static bending,free vibration,and buckling of the functionally graded sandwich plates wi...This study focusses on establishing the finite element model based on a new hyperbolic sheareformation theory to investigate the static bending,free vibration,and buckling of the functionally graded sandwich plates with porosity.The novel sandwich plate consists of one homogenous ceramic core and two different functionally graded face sheets which can be widely applied in many fields of engineering and defence technology.The discrete governing equations of motion are carried out via Hamilton’s principle and finite element method.The computation program is coded in MATLAB software and used to study the mechanical behavior of the functionally graded sandwich plate with porosity.The present finite element algorithm can be employed to study the plates with arbitrary shape and boundary conditions.The obtained results are compared with available results in the literature to confirm the reliability of the present algorithm.Also,a comprehensive investigation of the effects of several parameters on the bending,free vibration,and buckling response of functionally graded sandwich plates is presented.The numerical results shows that the distribution of porosity plays significant role on the mechanical behavior of the functionally graded sandwich plates。展开更多
The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate(HSP) by applying Green function method.Then an equivalent circuit model of the weakly-strongly coupled s...The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate(HSP) by applying Green function method.Then an equivalent circuit model of the weakly-strongly coupled system was proposed.Based on that,the estimation formulae of the coupled eigenfrequency were derived.The accuracy of the theoretical predictions was checked against experimental data,with good agreement achieved.Finally,the effects of HSP design parameters on the system coupling degree,the acoustic cavity eigenfrequency,and sound pressure response were analyzed.The results show that mechanical and acoustical characteristics of HSP can be improved by increasing the thickness of face sheet and reducing the mass density of material.展开更多
In this article,vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers subjected to blast load are studied.Higher-order ES-MITC3 element based on higher-order...In this article,vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers subjected to blast load are studied.Higher-order ES-MITC3 element based on higher-order shear deformation theory(HSDT)to achieve the governing equations.The sandwich plates with the ultra-light feature of the auxetic honeycomb core layer(negative Poisson’s ratio)and reinforced by two laminated three-phase skin layers.The obtained results in our work are compared with other previously published to confirm accuracy and reliability.In addition,the effects of parameters such as geometrical and material parameters on the vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers are fully investigated.展开更多
目的:探讨应用枕骨螺钉-棒-多轴螺钉内固定系统行枕颈固定融合术治疗“三明治”畸形伴寰枢关节脱位的临床效果。方法:回顾性分析2017年1月~2023年1月于我院因“三明治”畸形伴寰枢关节脱位行后路复位、植骨融合、枕颈内固定术的62例患者...目的:探讨应用枕骨螺钉-棒-多轴螺钉内固定系统行枕颈固定融合术治疗“三明治”畸形伴寰枢关节脱位的临床效果。方法:回顾性分析2017年1月~2023年1月于我院因“三明治”畸形伴寰枢关节脱位行后路复位、植骨融合、枕颈内固定术的62例患者,其中男性19例,女性43例,年龄51.1±23.5岁(29~72岁)。根据内固定系统枕骨端螺钉固定方式不同将患者分为两组:A组(38例)采用枕骨螺钉-棒-多轴螺钉内固定系统,男12例,女26例,年龄50.9±24.8岁(29~72岁),影像学表现脑干或颈髓受压30例、脊髓空洞6例、Chiari畸形2例;B组(24例)采用枕骨板-棒-多轴螺钉内固定系统,男7例,女17例,年龄51.4±22.4岁(32~69岁),影像学表现脑干或颈髓受压16例,脊髓空洞6例,Chiari畸形2例。A组随访时间36.5±11.8个月,B组随访时间36.1±9.8个月。两组患者年龄、性别、随访时间、影像表现无统计学差异(P>0.05)。收集并比较两组的术中出血量、手术时间、并发症发生率。术前及末次随访时进行颈部疼痛视觉模拟量表(visual analog scale,VAS)评分、颈椎功能障碍指数(neck disability index,NDI)、日本骨科协会(Japanese Orthopaedic Association,JOA)评分,术后1周及末次随访时测量两组患者CT植骨融合部横断面及矢状面骨性融合面积,术前、术后1周及末次随访时测量两组患者寰齿前间隙(atlantodental interval,ADI)、脊髓可用空间(space available for cord,SAC)、斜坡-椎管角(clivus canal angle,CCA)、延髓-脊髓角(cervico-medullary angle,CMA)。结果:A组术中出血量362.4±89.1mL、手术时间144.8±35.6min,B组术中出血量345.1±93.7mL、手术时间143.7±36.2min,两组间无统计学差异(P>0.05)。随访期间两组均无脊髓损伤、脑脊液漏等严重并发症发生,B组有2例患者出现连接棒断裂,3例患者出现复位丢失。两组术前NDI、VAS评分、JOA评分与末次随访比较有显著性差异(P<0.05),两组同时间点比较均无统计学差异(P>0.05)。两组术前ADI、SAC、CCA、CMA与术后1周及末次随访比较有显著性差异(P<0.05),两组同时间点比较均无统计学差异(P>0.05)。A组术后1周植骨融合部横断面面积、植骨融合部矢状面面积分别为385.44±84.51mm^(2)、290.28±110.41mm^(2),末次随访时分别为267.06±66.13mm^(2)、204.54±83.85mm^(2);B组术后1周分别为442.61±76.85mm^(2)、267.21±104.63mm^(2),末次随访时分别为172.43±37.37mm^(2)、124.87±48.10mm^(2),两组术后1周植骨融合部横断面面积和植骨融合部矢状面面积比较无统计学差异(P>0.05),末次随访时有显著性差异(P<0.05)。结论:应用枕骨螺钉-棒-多轴螺钉内固定系统枕颈固定融合术治疗“三明治”畸形伴寰枢关节脱位同枕骨板-多轴螺钉内固定系统相比疗效相当,但术后植骨融合效果更好,能达到可靠的枕颈固定。展开更多
基金the funding of the Deanship of Graduate Studies and Scientific Research,Jazan University,Saudi Arabia,through project number:RG24-M027.
文摘This study presents a significant advancement in the vibration analysis of functionally graded sandwich plates with auxetic cores by introducing a general viscoelastic foundation model that more accurately reflects the complex interactions between the plate and the foundation.The novelty of this study is that the proposed viscoelastic foundation model incorporates elastic and damping effects in both the Winkler and Pasternak layers.To develop the theoretical framework for this analysis,the higher-order shear deformation theory is employed,while Hamilton's principle is used to derive the governing equations of motion.The closed-form solution is used to determine the damped vibration behaviors of the sandwich plates.The precision and robustness of the proposed mathematical model are validated through several comparison studies with existing numerical results.A detailed parametric study is conducted to investigate the influence of various parameters,including the elastic and damping coefficients of the foundation,the material gradation,and the properties of the auxetic core on the vibration behavior of the plates.The numerical results provide new insights into the vibration characteristics of sandwich plates with auxetic cores resting on viscoelastic foundation,highlighting the significant role of the two damping coefficients and auxetic cores in the visco-vibration behavior of the plates.
文摘This study focusses on establishing the finite element model based on a new hyperbolic sheareformation theory to investigate the static bending,free vibration,and buckling of the functionally graded sandwich plates with porosity.The novel sandwich plate consists of one homogenous ceramic core and two different functionally graded face sheets which can be widely applied in many fields of engineering and defence technology.The discrete governing equations of motion are carried out via Hamilton’s principle and finite element method.The computation program is coded in MATLAB software and used to study the mechanical behavior of the functionally graded sandwich plate with porosity.The present finite element algorithm can be employed to study the plates with arbitrary shape and boundary conditions.The obtained results are compared with available results in the literature to confirm the reliability of the present algorithm.Also,a comprehensive investigation of the effects of several parameters on the bending,free vibration,and buckling response of functionally graded sandwich plates is presented.The numerical results shows that the distribution of porosity plays significant role on the mechanical behavior of the functionally graded sandwich plates。
基金Project(51105375)supported by the National Natural Science Foundation of ChinaProject(CSTC2010BB8204)supported by Chongqing Natural Science Foundation,China
文摘The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate(HSP) by applying Green function method.Then an equivalent circuit model of the weakly-strongly coupled system was proposed.Based on that,the estimation formulae of the coupled eigenfrequency were derived.The accuracy of the theoretical predictions was checked against experimental data,with good agreement achieved.Finally,the effects of HSP design parameters on the system coupling degree,the acoustic cavity eigenfrequency,and sound pressure response were analyzed.The results show that mechanical and acoustical characteristics of HSP can be improved by increasing the thickness of face sheet and reducing the mass density of material.
文摘In this article,vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers subjected to blast load are studied.Higher-order ES-MITC3 element based on higher-order shear deformation theory(HSDT)to achieve the governing equations.The sandwich plates with the ultra-light feature of the auxetic honeycomb core layer(negative Poisson’s ratio)and reinforced by two laminated three-phase skin layers.The obtained results in our work are compared with other previously published to confirm accuracy and reliability.In addition,the effects of parameters such as geometrical and material parameters on the vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers are fully investigated.
文摘目的:探讨应用枕骨螺钉-棒-多轴螺钉内固定系统行枕颈固定融合术治疗“三明治”畸形伴寰枢关节脱位的临床效果。方法:回顾性分析2017年1月~2023年1月于我院因“三明治”畸形伴寰枢关节脱位行后路复位、植骨融合、枕颈内固定术的62例患者,其中男性19例,女性43例,年龄51.1±23.5岁(29~72岁)。根据内固定系统枕骨端螺钉固定方式不同将患者分为两组:A组(38例)采用枕骨螺钉-棒-多轴螺钉内固定系统,男12例,女26例,年龄50.9±24.8岁(29~72岁),影像学表现脑干或颈髓受压30例、脊髓空洞6例、Chiari畸形2例;B组(24例)采用枕骨板-棒-多轴螺钉内固定系统,男7例,女17例,年龄51.4±22.4岁(32~69岁),影像学表现脑干或颈髓受压16例,脊髓空洞6例,Chiari畸形2例。A组随访时间36.5±11.8个月,B组随访时间36.1±9.8个月。两组患者年龄、性别、随访时间、影像表现无统计学差异(P>0.05)。收集并比较两组的术中出血量、手术时间、并发症发生率。术前及末次随访时进行颈部疼痛视觉模拟量表(visual analog scale,VAS)评分、颈椎功能障碍指数(neck disability index,NDI)、日本骨科协会(Japanese Orthopaedic Association,JOA)评分,术后1周及末次随访时测量两组患者CT植骨融合部横断面及矢状面骨性融合面积,术前、术后1周及末次随访时测量两组患者寰齿前间隙(atlantodental interval,ADI)、脊髓可用空间(space available for cord,SAC)、斜坡-椎管角(clivus canal angle,CCA)、延髓-脊髓角(cervico-medullary angle,CMA)。结果:A组术中出血量362.4±89.1mL、手术时间144.8±35.6min,B组术中出血量345.1±93.7mL、手术时间143.7±36.2min,两组间无统计学差异(P>0.05)。随访期间两组均无脊髓损伤、脑脊液漏等严重并发症发生,B组有2例患者出现连接棒断裂,3例患者出现复位丢失。两组术前NDI、VAS评分、JOA评分与末次随访比较有显著性差异(P<0.05),两组同时间点比较均无统计学差异(P>0.05)。两组术前ADI、SAC、CCA、CMA与术后1周及末次随访比较有显著性差异(P<0.05),两组同时间点比较均无统计学差异(P>0.05)。A组术后1周植骨融合部横断面面积、植骨融合部矢状面面积分别为385.44±84.51mm^(2)、290.28±110.41mm^(2),末次随访时分别为267.06±66.13mm^(2)、204.54±83.85mm^(2);B组术后1周分别为442.61±76.85mm^(2)、267.21±104.63mm^(2),末次随访时分别为172.43±37.37mm^(2)、124.87±48.10mm^(2),两组术后1周植骨融合部横断面面积和植骨融合部矢状面面积比较无统计学差异(P>0.05),末次随访时有显著性差异(P<0.05)。结论:应用枕骨螺钉-棒-多轴螺钉内固定系统枕颈固定融合术治疗“三明治”畸形伴寰枢关节脱位同枕骨板-多轴螺钉内固定系统相比疗效相当,但术后植骨融合效果更好,能达到可靠的枕颈固定。
