Contrary to conventional design methods that assume uniform and slow temperature changes tied to atmospheric conditions,single-layer spherical reticulated shells undergo significant non-uniform and time-variant temper...Contrary to conventional design methods that assume uniform and slow temperature changes tied to atmospheric conditions,single-layer spherical reticulated shells undergo significant non-uniform and time-variant temperature variations due to dynamic environmental coupling.These differences can affect structural performance and pose safety risks.Here,a systematic numerical method was developed and applied to simulate long-term temperature variations in such a structure under real environmental conditions,revealing its non-uniform distribution characteristics and time-variant regularity.A simplified design method for non-uniform thermal loads,accounting for time-variant environmental factors,was theoretically derived and validated through experiments and simulations.The maximum deviation and mean error rate between calculated and tested results were 6.1℃ and 3.7%,respectively.Calculated temperature fields aligned with simulated ones,with deviations under 6.0℃.Using the design method,non-uniform thermal effects of the structure are analyzed.Maximum member stress and nodal displacement under non-uniform thermal loads reached 119.3 MPa and 19.7 mm,representing increases of 167.5%and 169.9%,respectively,compared to uniform thermal loads.The impacts of healing construction time on non-uniform thermal effects were evaluated,resulting in construction recommendations.The methodologies and conclusions presented here can serve as valuable references for the thermal design,construction,and control of single-layer spherical reticulated shells or similar structures.展开更多
The effects of different parameters on the nonlinear dynamic characteristics of macrofiber composite(MFC)microsheet with graphene(GP)skin under non-uniform thermal field are investigated.Firstly,the physical parameter...The effects of different parameters on the nonlinear dynamic characteristics of macrofiber composite(MFC)microsheet with graphene(GP)skin under non-uniform thermal field are investigated.Firstly,the physical parameters of the MFC–GP structure are calculated by the mixing rule,and the constitutive equations of the structure are set up by employing the Eringen theory.The nonlinear dynamic equations of the microsheet are obtained by using Hamilton’s principle.Then,the heat conduction equations of the microsheet are considered,adopting Green and Naghdi’s generalized thermoelasticity theory.According to the Galerkin weighted residual method,the thermoelasticity coupling equations of the structure are obtained.Meanwhile,the influence of the positive piezoelectric effect of GP and MFC on the vibration response of the structure is also investigated.The nonlinear dynamic governing equations including displacement,coupled thermoelasticity,and electricity field are discretized by the Galerkin method.The effects of non-local parameter,volume fraction of GP,and thermal and electricity coupling coefficients on structural dynamic behavior are discussed in the numerical simulation.展开更多
提出了一种基于有限元法和有限体积法的变压器三维电磁-流体-温度场耦合分析方法。通过建立变压器三维模型,采用有限元法分析变压器内磁通密度分布,并求得变压器及绕组损耗。将变压器铁芯及绕组损耗作为热源,采用有限体积法求解变压器流...提出了一种基于有限元法和有限体积法的变压器三维电磁-流体-温度场耦合分析方法。通过建立变压器三维模型,采用有限元法分析变压器内磁通密度分布,并求得变压器及绕组损耗。将变压器铁芯及绕组损耗作为热源,采用有限体积法求解变压器流体-温度场,分析变压器内部油流及温度分布,同时根据温度场结果对变压器损耗进行修正,通过迭代求解变压器流体-温度场获取变压器内部最终温度分布结果,提高求解精度。采用所提方法对35 k V油浸式变压器进行三维电磁-流体-温度场分析,将结果与经验公式的热点温度计算结果进行对比,验证了所提方法的有效性和正确性。展开更多
基金This work is supported by the National Natural Science Foundation of China(Nos.51578491 and 52238001).
文摘Contrary to conventional design methods that assume uniform and slow temperature changes tied to atmospheric conditions,single-layer spherical reticulated shells undergo significant non-uniform and time-variant temperature variations due to dynamic environmental coupling.These differences can affect structural performance and pose safety risks.Here,a systematic numerical method was developed and applied to simulate long-term temperature variations in such a structure under real environmental conditions,revealing its non-uniform distribution characteristics and time-variant regularity.A simplified design method for non-uniform thermal loads,accounting for time-variant environmental factors,was theoretically derived and validated through experiments and simulations.The maximum deviation and mean error rate between calculated and tested results were 6.1℃ and 3.7%,respectively.Calculated temperature fields aligned with simulated ones,with deviations under 6.0℃.Using the design method,non-uniform thermal effects of the structure are analyzed.Maximum member stress and nodal displacement under non-uniform thermal loads reached 119.3 MPa and 19.7 mm,representing increases of 167.5%and 169.9%,respectively,compared to uniform thermal loads.The impacts of healing construction time on non-uniform thermal effects were evaluated,resulting in construction recommendations.The methodologies and conclusions presented here can serve as valuable references for the thermal design,construction,and control of single-layer spherical reticulated shells or similar structures.
基金The authors gratefully acknowledge the support of the National Natural Science Foundation of China(NNSFC)through Grant Nos.11772010 and 11832002the Funding Project for High-Level Teachers’Team Construction in Beijing Municipal Colleges and Universities.
文摘The effects of different parameters on the nonlinear dynamic characteristics of macrofiber composite(MFC)microsheet with graphene(GP)skin under non-uniform thermal field are investigated.Firstly,the physical parameters of the MFC–GP structure are calculated by the mixing rule,and the constitutive equations of the structure are set up by employing the Eringen theory.The nonlinear dynamic equations of the microsheet are obtained by using Hamilton’s principle.Then,the heat conduction equations of the microsheet are considered,adopting Green and Naghdi’s generalized thermoelasticity theory.According to the Galerkin weighted residual method,the thermoelasticity coupling equations of the structure are obtained.Meanwhile,the influence of the positive piezoelectric effect of GP and MFC on the vibration response of the structure is also investigated.The nonlinear dynamic governing equations including displacement,coupled thermoelasticity,and electricity field are discretized by the Galerkin method.The effects of non-local parameter,volume fraction of GP,and thermal and electricity coupling coefficients on structural dynamic behavior are discussed in the numerical simulation.
文摘提出了一种基于有限元法和有限体积法的变压器三维电磁-流体-温度场耦合分析方法。通过建立变压器三维模型,采用有限元法分析变压器内磁通密度分布,并求得变压器及绕组损耗。将变压器铁芯及绕组损耗作为热源,采用有限体积法求解变压器流体-温度场,分析变压器内部油流及温度分布,同时根据温度场结果对变压器损耗进行修正,通过迭代求解变压器流体-温度场获取变压器内部最终温度分布结果,提高求解精度。采用所提方法对35 k V油浸式变压器进行三维电磁-流体-温度场分析,将结果与经验公式的热点温度计算结果进行对比,验证了所提方法的有效性和正确性。
