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Structural design of the fluted shaped charge liner using multi-section optimization method
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作者 Shengjie Sun Jianwei Jiang +2 位作者 Shuyou Wang Jianbing Men Mei Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第7期249-262,共14页
Spin effect of the small diameter shaped charge results in the centrifugal stress during the jet stretching process. Consequently, the jet scatters, which deceases the jet penetration capability. In the present study,... Spin effect of the small diameter shaped charge results in the centrifugal stress during the jet stretching process. Consequently, the jet scatters, which deceases the jet penetration capability. In the present study, a multi-section method was proposed to design the spin-compensation liner. The spincompensation rate(SCR) of the liner was defined as the specific angular velocity that a fluted liner can offset. Based on the plain stress theory, SPH numerical method was applied to study the converging process of the 2D fluted structure. The spin-compensation mechanism of the fluted structure was illustrated. Then, nine cross sections were chosen along the liner axis equidistantly. On each of the section, a 2D fluted structure was designed to offset a given initial angular velocity. After, the optimized fluted structures were integrated into a 3D fluted liner. Jet appearances of the normal liner and the fluted liners under different initial angular velocities were compared, which verifies the practicality of the multi-sectional method. The multi-section optimization method provides a new efficient method of designing the shaped charge liner for a specific usage. 展开更多
关键词 Fluted liner Spin-compensation SPH structural optimization
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Running safety and seismic optimization of a fault-crossing simply-supported girder bridge for high-speed railways based on a train-track-bridge coupling system 被引量:10
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作者 JIANG Hui ZENG Cong +3 位作者 PENG Qiang LI Xin MAXin-yi SONG Guang-song 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第8期2449-2466,共18页
Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under earthquakes.Taking a high-speed railway simply-sup... Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under earthquakes.Taking a high-speed railway simply-supported girder bridge with eight spans crossing an active strike-slip fault as the research object,a refined coupling dynamic model of the high-speed train-CRTS III slab ballastless track-bridge system was established based on ABAQUS.The rationality of the established model was thoroughly discussed.The horizontal ground motions in a fault rupture zone were simulated and transient dynamic analyses of the high-speed train-track-bridge coupling system under 3-dimensional seismic excitations were subsequently performed.The safe running speed limits of a high-speed train under different earthquake levels(frequent occurrence,design and rare occurrence)were assessed based on wheel-rail dynamic(lateral wheel-rail force,derailment coefficient and wheel-load reduction rate)and rail deformation(rail dislocation,parallel turning angle and turning angle)indicators.Parameter optimization was then investigated in terms of the rail fastener stiffness and isolation layer friction coefficient.Results of the wheel-rail dynamic indicators demonstrate the safe running speed limits for the high-speed train to be approximately 200 km/h and 80 km/h under frequent and design earthquakes,while the train is unable to run safely under rare earthquakes.In addition,the rail deformations under frequent,design and rare earthquakes meet the safe running requirements of the high-speed train for the speeds of 250,100 and 50 km/h,respectively.The speed limits determined for the wheel-rail dynamic indicators are lower due to the complex coupling effect of the train-track-bridge system under track irregularity.The running safety of the train was improved by increasing the fastener stiffness and isolation layer friction coefficient.At the rail fastener lateral stiffness of 60 kN/mm and isolation layer friction coefficients of 0.9 and 0.8,respectively,the safe running speed limits of the high-speed train increased to 250 km/h and 100 km/h under frequent and design earthquakes,respectively. 展开更多
关键词 high-speed train train-track-bridge interaction fault-crossing ground motion train operation safety speed limit track structure optimization
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Optimal design of structural parameters for shield cutterhead based on fuzzy mathematics and multi-objective genetic algorithm 被引量:12
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作者 夏毅敏 唐露 +2 位作者 暨智勇 程永亮 卞章括 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期937-945,共9页
In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters ... In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated,based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress-strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%. 展开更多
关键词 shield tunneling machine cutterhead structural parameters fuzzy mathematics finite element optimization
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Contrastive analysis and crashworthiness optimization of two composite thin-walled structures 被引量:4
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作者 谢素超 周辉 +1 位作者 梁习锋 任鑫 《Journal of Central South University》 SCIE EI CAS 2014年第11期4386-4394,共9页
For the safety protection of passengers when train crashes occur, special structures are crucially needed as a kind of indispensable energy absorbing device. With the help of the structures, crash kinetic-energy can b... For the safety protection of passengers when train crashes occur, special structures are crucially needed as a kind of indispensable energy absorbing device. With the help of the structures, crash kinetic-energy can be completely absorbed or dissipated for the aim of safety. Two composite structures(circumscribed circle structure and inscribed circle structure) were constructed. In addition, comparison and optimization of the crashworthy characteristic of the two structures were carried out based on the method of explicit finite element analysis(FEA) and Kriging surrogate model. According to the result of Kriging surrogate model, conclusions can be safely drawn that the specific energy absorption(SEA) and ratio of specific energy absorption to initial peak force(REAF) of circumscribed circle structure are lager than those of inscribed circle structure under the same design parameters. In other words, circumscribed circle structure has better performances with higher energy-absorbing ability and lower initial peak force. Besides, error analysis was adopted and the result of which indicates that the Kriging surrogate model has high nonlinear fitting precision. What is more, the SEA and REAF optimum values of the two structures have been obtained through analysis, and the crushing results have been illustrated when the two structures reach optimum SEA and REAF. 展开更多
关键词 contrastive analysis crashworthiness optimization composite structure Kriging surrogate model finite element analysis
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Comparison on construction of strut-and-tie models for reinforced concrete deep beams 被引量:2
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作者 仇一颗 刘霞 《Journal of Central South University》 SCIE EI CAS 2011年第5期1685-1692,共8页
With consideration of the differences between concrete and steel,three solutions using genetic evolutionary structural optimization algorithm were presented to automatically develop optimal strut-and-tie model for dee... With consideration of the differences between concrete and steel,three solutions using genetic evolutionary structural optimization algorithm were presented to automatically develop optimal strut-and-tie model for deep beams.In the finite element analysis of the first method,the concrete and steel rebar are modeled by a plane element and a bar element,respectively.In the second method,the concrete and steel are assigned to two different plane elements,whereas in the third method only one kind of plane element is used with no consideration of the differences of the two materials.A simply supported beam under two point loads was presented as an example to verify the validity of the three proposed methods.The results indicates that all the three methods can generate optimal strut-and-tie models and the third algorithm has powerful capability in searching more optimal results with less computational effort.The effectiveness of the proposed algorithm III has also been demonstrated by other two examples. 展开更多
关键词 reinforced concrete deep beam topology optimization strut-and-tie model genetic evolutionary structural optimization
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Optimum Combination Test of Erosion Gully in Black Soil Regions by Coal Gangue Reconstruction Soil
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作者 Wang Zhong-bo Li Dian-xing +1 位作者 Zhang Jin-bo Wang Bin 《Journal of Northeast Agricultural University(English Edition)》 CAS 2021年第3期77-87,共11页
The black soil area in northeast China is greatly affected by hydraulic erosion.To inhibit the development of gully cutting and the secondary erosion on farmland,different size coal gangues and covering soils with cha... The black soil area in northeast China is greatly affected by hydraulic erosion.To inhibit the development of gully cutting and the secondary erosion on farmland,different size coal gangues and covering soils with change thicknesses combinations were selected to fill in-situ gully for hydraulic performance experiment.The hydraulic performance indexes of different combinations of large and small size gangue thicknesses and covering soil thicknesses were analyzed by the extreme learning machine(ELM)and particle swarm optimization(PSO).The results showed that the structure of large and small size coal gangues and surface soil under different thicknesses was affected by hydraulic and gravity.With the change of the thicknesses of coal gangue and covering soil,its effective channel and vertical infiltration process became more and more stable with the increase in drainage time,while the structure of small size coal gangue was the main hydraulic factor in reconstructed soil structure(p=0.016).The overall drainage performance showed a single peak trend,the optimal combination of drainage parameters and structure thickness was relatively concentrated;the drainage time parameters of different composite structures were found to have a certain linear relationship;the Pareto optimum of drainage performance was determined.The optimum thickness was 30-40 cm for large-sized gangue,30-60 cm for small-sized gangue,and 50-70 cm for covering soil,to meet the relatively good drainage performance and to ensure that secondary erosion was reduced,so as to achieve the purpose of controlling the gully. 展开更多
关键词 soil reconstruction coal gangue drainage performance structural optimization
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The technology and mechanism of removal of plastic mulch and land preparation
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作者 ZHANG Huiyou HOU Shulin +2 位作者 NA Mingjun YANG Xiaoli BAI Shengnan 《Journal of Northeast Agricultural University(English Edition)》 CAS 2007年第1期72-75,共4页
In this article,the characteristic of the field plastic mulch, the craft for mechanization removal and land preparation of plastic mulch and the mechanism frequently used in the removal and land preparation of plasti... In this article,the characteristic of the field plastic mulch, the craft for mechanization removal and land preparation of plastic mulch and the mechanism frequently used in the removal and land preparation of plastic mulch were introduced, which offered references for the design of removal mechanism and land preparation of plastic mulch and structural optimization combination of working components. 展开更多
关键词 mechanism for removal and land preparation removal of plastic film land preparation mechanism structural optimization
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Multi-objective optimisation of a vehicle energy absorption structure based on surrogate model 被引量:4
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作者 谢素超 周辉 《Journal of Central South University》 SCIE EI CAS 2014年第6期2539-2546,共8页
In order to optimize the crashworthy characteristic of energy-absorbing structures, the surrogate models of specific energy absorption (SEA) and ratio of SEA to initial peak force (REAF) with respect to the design... In order to optimize the crashworthy characteristic of energy-absorbing structures, the surrogate models of specific energy absorption (SEA) and ratio of SEA to initial peak force (REAF) with respect to the design parameters were respectively constructed based on surrogate model optimization methods (polynomial response surface method (PRSM) and Kriging method (KM)). Firstly, the sample data were prepared through the design of experiment (DOE). Then, the test data models were set up based on the theory of surrogate model, and the data samples were trained to obtain the response relationship between the SEA &amp; REAF and design parameters. At last, the structure optimal parameters were obtained by visual analysis and genetic algorithm (GA). The results indicate that the KM, where the local interpolation method is used in Gauss correlation function, has the highest fitting accuracy and the structure optimal parameters are obtained as: the SEA of 29.8558 kJ/kg (corresponding toa=70 mm andt= 3.5 mm) and REAF of 0.2896 (corresponding toa=70 mm andt=1.9615 mm). The basis function of the quartic PRSM with higher order than that of the quadratic PRSM, and the mutual influence of the design variables are considered, so the fitting accuracy of the quartic PRSM is higher than that of the quadratic PRSM. 展开更多
关键词 railway vehicle energy-absorbing structure surrogate model Kriging method (KM) polynomial response surface method (PRSM) structure optimization
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Influence of shaped charge structure parameters on the formation of linear explosively formed projectiles 被引量:4
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作者 Tian-bao Ma Jing Liu Qi Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第10期1863-1874,共12页
The research of LEFP(linear explosive forming projectile)is of great value to the development of new warhead due to its excellent performance.To further improve the damage ability of the shaped charge warhead,a specia... The research of LEFP(linear explosive forming projectile)is of great value to the development of new warhead due to its excellent performance.To further improve the damage ability of the shaped charge warhead,a special shell overhanging structure was designed to increase the charge based on the traditional spherical charge,in which case the crushing energy of LEFP could be guaranteed.LS-DYNA was used to simulate different charge structures obtained by changing the number of detonation points,the length of shell platform,the radius of curvature and the thickness of liner.The RSM(response surface model)between the molding parameters of LEFP and the structural parameters of charge was established.Based on RSM model,the structure of shaped charge was optimized by using multi-objective genetic algorithm.Meanwhile,the formation process of jet was analyzed by pulsed X-ray photography.The results show that the velocity,length-diameter ratio and specific kinetic energy of the LEFP were closely related to the structural parameters of the shaped charge.After the optimization of charge structure,the forming effect and penetration ability of LEPP had been significantly improved.The experimental data of jet velocity and length were consistent with the numerical results,which verifies the reliability of the numerical results. 展开更多
关键词 LEFP Numerical simulation Shaped charge Structure optimization
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Learning Bayesian network structure with immune algorithm 被引量:4
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作者 Zhiqiang Cai Shubin Si +1 位作者 Shudong Sun Hongyan Dui 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第2期282-291,共10页
Finding out reasonable structures from bulky data is one of the difficulties in modeling of Bayesian network (BN), which is also necessary in promoting the application of BN. This pa- per proposes an immune algorith... Finding out reasonable structures from bulky data is one of the difficulties in modeling of Bayesian network (BN), which is also necessary in promoting the application of BN. This pa- per proposes an immune algorithm based method (BN-IA) for the learning of the BN structure with the idea of vaccination. Further- more, the methods on how to extract the effective vaccines from local optimal structure and root nodes are also described in details. Finally, the simulation studies are implemented with the helicopter convertor BN model and the car start BN model. The comparison results show that the proposed vaccines and the BN-IA can learn the BN structure effectively and efficiently. 展开更多
关键词 structure learning Bayesian network immune algorithm local optimal structure VACCINATION
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Finite element and experimental analysis of pinion bracket-assembly of three gorges project ship lift 被引量:2
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作者 石端伟 汪勇波 +2 位作者 彭惠 赵铁柱 程术潇 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第4期1307-1314,共8页
The pinion bracket-assembly(PBA) is a major part of three gorges project(TGP) ship lift drive system. The static strength,fatigue strength and stress distribution of hinge pin of PBA were analyzed by ANSYS, and the st... The pinion bracket-assembly(PBA) is a major part of three gorges project(TGP) ship lift drive system. The static strength,fatigue strength and stress distribution of hinge pin of PBA were analyzed by ANSYS, and the structure of PBA was optimized. The results show that after the optimization, the maximum comprehensive stress is 259.59 MPa, the maximum fatigue cumulative damage of weld joints is 0.94 and the maximum vertical deformation of hinge pin is 0.14 mm. The elastic deformation, hydropneumatic spring cylinder(HSC) load response and the vibration characteristics of PBA were studied by the bearing test when PBA bore the load caused by different water level errors. The results indicate that when the water level of ship chamber ranges from 3.4 m to 3.6 m,the vertical elastic deformation of the pinion shaft is between-8.58 and 10.50 mm. When upward outage-load(1580 k N) is imposed by the test-rack, the vertical elastic deformation of the pinion shaft is 13.42 and 14.07 mm and HSC load response is 795.80-800.80 k N. In the process of imposing load on the pinion by the test-rack, the maximum vibration amplitude and acceleration of PBA internal components are 0.37° and 2.67 rad/s2, respectively; the maximum impact on the pin caused by vibration is 19.89 k N; the pinion shaft vertical displacement and HSC load response do not fluctuate. There is a great difference between the frequency of meshing force of the pinion and the rack(1.06 Hz) and first-order natural frequency of PBA(8.41 Hz), thus PBA will not resonate.From all above, PBA meets the static strength and fatigue strength requirements. The vibration of PBA internal components has no effect on the vertical displacement of the pinion shaft, HSC load response and smooth operation of PBA. There is a liner relationship in the ratio of 2:1 between the thrust imposed by the test-rack and HSC load, thus HSC can limit the load imposed on the pinion. 展开更多
关键词 three gorges project ship lift pinion bracket-assembly FEM fatigue strength structure optimization vibration
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