期刊文献+
共找到671篇文章
< 1 2 34 >
每页显示 20 50 100
Study on buffering performance of thin-walled metal tube with different angles 被引量:3
1
作者 Qun Liu Wen-tao Wang Wen-feng Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2018年第6期702-708,共7页
High frequency shock load is often generated during pyrotechnic device working, which is detrimental to spacecraft structures and electric devices. Therefore, it is valuable to reduce the shock load in pyrotechnic dev... High frequency shock load is often generated during pyrotechnic device working, which is detrimental to spacecraft structures and electric devices. Therefore, it is valuable to reduce the shock load in pyrotechnic device design. Actually, there are several ways to decrease pyroshock loads, such as reduction of powder,installation of buffering structure, insulation of damageable devices, and so on. Considered assuring the function of pyrotechnic device and minimum of structure modification, shock absorbing structure is more propitious to be introduced in pyrotechnic device. In this paper, based on the method of thinwalled metal tube diameter-expanding, a thin-walled tube shock buffering structure was designed on a separate bolt. Built on the simplified structure of a separate bolt, the model of cone piston impacting thin-walled tube absorber was established, and the thin-walled tube shock absorbing characteristics and the relation between cone angles and absorber performance were analyzed. The results showed that the change of buffering force of thin-walled tube could be divided into four phases, and each phase was correspondent to the cone piston structure. In addition, as the cone angle increases, the max shock acceleration changes in the style of decrease-increase-decrease-increase, which is the result of coupled effects of cone piston max enter depth, buffering force and energy loss. In short, these results could establish the relationships between thin-walled tube absorbing performance and its structure, which is of significance to develop low-shock pyrotechnic device. 展开更多
关键词 Pyroshock Shock absorbing thin-walled metal tube
下载PDF
A novel efficient energy absorber with free inversion of a metal foam-filled circular tube
2
作者 Jianxun ZHANG Jinwen BAI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第1期1-14,共14页
In this paper, a novel efficient energy absorber with free inversion of a metal foam-filled circular tube(MFFCT) is designed, and the axial compressive behavior of the MFFCT under free inversion is studied analyticall... In this paper, a novel efficient energy absorber with free inversion of a metal foam-filled circular tube(MFFCT) is designed, and the axial compressive behavior of the MFFCT under free inversion is studied analytically and numerically. The theoretical analysis reveals that the energy is mainly dissipated through the radial bending of the metal circular tube, the circumferential expansion of the metal circular tube, and the metal filled-foam compression. The principle of energy conservation is used to derive the theoretical formula for the minimum compressive force of the MFFCT over free inversion under axial loading. Furthermore, the free inversion deformation characteristics of the MFFCT are analyzed numerically. The theoretical steady values are found to be in good agreement with the results of the finite element(FE) analysis. The effects of the average diameter of the metal tube, the wall thickness of the metal tube, and the filled-foam strength on the free inversion deformation of the MFFCT are considered. It is observed that in the steady deformation stage, the load-carrying and energy-absorbing capacities of the MFFCT increase with the increase in the average diameter of the metal tube, the wall thickness of the metal tube, or the filled-foam strength. The specific energy absorption(SEA) of free inversion of the MFFCT is significantly higher than that of the metal tube alone. 展开更多
关键词 metal foam-filled circular tube(MFFCT) free inversion load-carrying capacity energy absorption
下载PDF
Sensitivity of springback and section deformation to process parameters in rotary draw bending of thin-walled rectangular H96 brass tube 被引量:8
3
作者 朱英霞 刘郁丽 杨合 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第9期2233-2240,共8页
In order to study the effects of the process parameters on springback and section deformation, a sensitivity analysis model was established based on the combination use of the multi-parameter sensitivity analysis meth... In order to study the effects of the process parameters on springback and section deformation, a sensitivity analysis model was established based on the combination use of the multi-parameter sensitivity analysis method and the springback/section deformation prediction finite element model, and by using this model the sensitivities of the springback and the section deformation to process parameters were analyzed and compared. The results show that the most sensitive process conditions for springback angle are the boost speed and the pressure of pressure die, and the most sensitive process condition for section deformation is the number of cores. When the clamp force, the boost speed and the pressure of pressure die are utilized to control section deformation, the effect of these process parameters on springback should be considered. When the process parameters are mainly used to control springback, the effect of these process parameters on the section deformation should be always considered. 展开更多
关键词 thin-walled rectangular H96 brass tube rotary draw bending sensitivity analysis SPRINGBACK section deformation
下载PDF
Warm bending mechanism of extrados and intrados of large diameter thin-walled CP-Ti tubes 被引量:2
4
作者 张晓丽 杨合 +2 位作者 李恒 张志勇 李龙 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第10期3257-3264,共8页
In order to develop the warming bending technology of the large diameter thin-walled(LDTW) commercial pure titanium alloy CP-Ti tubes, the warm bending mechanism of the extrados and intrados of LDTW CP-Ti tubes was ... In order to develop the warming bending technology of the large diameter thin-walled(LDTW) commercial pure titanium alloy CP-Ti tubes, the warm bending mechanism of the extrados and intrados of LDTW CP-Ti tubes was researched. By EBSD analysis and Vickers hardness test, the changes of microstructure and strength of the tubes at different bending temperatures of 293, 423 and 573 K, were analyzed. The results show: 1) The extrados of the bent tube deforms mainly by slip, along with few twinning, and the preferred orientation is similar to that of the initial tube; the intrados of the bent tube experiences compression deformation mainly by {1 012} tensile twinning, and the twinning makes the preferred orientation of wall materials change sharply. 2) The Vickers hardness values of both the extrados and intrados of the samples after bending increase greatly; the Vickers hardness values of the intrados are much higher than those of the extrados, and Vickers hardness values of the RD-TD planes are always higher than those of the RD-LD planes, which are related to the different deformation mechanisms. 展开更多
关键词 large diameter thin-walled CP-Ti bent tube warm bending texture TWINNING deformation mechanism
下载PDF
Significance-based optimization of processing parameters for thin-walled aluminum alloy tube NC bending with small bending radius 被引量:13
5
作者 XU Jie YANG He +1 位作者 LI Heng ZHAN Mei 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第1期147-156,共10页
Thin-walled aluminum alloy tube numerical control (NC) bending with small bending radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of... Thin-walled aluminum alloy tube numerical control (NC) bending with small bending radius is a complex process with multi-factor coupling effects and multi-die constraints. A significance-based optimization method of the parameters was proposed based on the finite element (FE) simulation, and the significance analysis of the processing parameters on the forming quality in terms of the maximum wall thinning ratio and the maximum cross section distortion degree was implemented using the fractional factorial design. The optimum value of the significant parameter, the clearance between the tube and the wiper die, was obtained, and the values of the other parameters, including the friction coefficients and the clearances between the tube and the dies, the mandrel extension length and the boost velocity were estimated. The results are applied to aluminum alloy tube NC bending d50 mm×1 mm×75 mm and d70 mm×1.5 mm×105 mm (initial tube outside diameter D0 × initial tube wall thickness t0 × bending radius R), and qualified tubes are produced. 展开更多
关键词 thin-walled aluminum alloy tube OPTIMIZATION finite element (FE) numerical control bending processing parameters significance analysis small bending radius
下载PDF
Cross-sectional distortion behaviors of thin-walled rectangular tube in rotary-draw bending process 被引量:7
6
作者 赵刚要 刘郁丽 +1 位作者 杨合 卢彩红 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第3期484-489,共6页
The cross-sectional distortion usually appears during rotary-draw bending process of thin-walled rectangular tube with small bending radius.To study the cross-sectional distortion of the tube,a three-dimensional finit... The cross-sectional distortion usually appears during rotary-draw bending process of thin-walled rectangular tube with small bending radius.To study the cross-sectional distortion of the tube,a three-dimensional finite-element model of the process was developed based on ABAQUS/Explicit code and its reliability was validated by experiment.Then,the cross-sectional distortion behaviors of the tube were investigated.The results show that a zone of larger circumferential stress appears on the tube when bending angle reaches 30°.And in the larger circumferential stress zone,the sagging phenomenon is produced obviously.The maximum cross-sectional distortion is located in the larger circumferential stress zone and the angle between the plane of maximum cross-sectional distortion and the bending reference plane is about 50°.The position of the maximum cross-sectional distortion keeps almost unchanged with the variation of the clearances between dies and tube. 展开更多
关键词 thin-walled rectangular tube aluminum alloy 3A21 rotary-draw bending cross-sectional distortion die clearance
下载PDF
Deformation Calculation of Cross-section Based on Virtual Force in Thin-walled Tube Bending Process 被引量:5
7
作者 LIU Jingyao TANG Chengtong NING Ruxin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第5期696-701,共6页
Cross-section deformation is one of important factors affecting the quality of tube formation, and the tube's capability of transporting liquid and gas will be reduced because of the cross-section ellipse deformation... Cross-section deformation is one of important factors affecting the quality of tube formation, and the tube's capability of transporting liquid and gas will be reduced because of the cross-section ellipse deformation due to the effect of shear load in plastic bending process. When the tube is bent, the extrados-wall bears the tension stress and the intrados-wall bears the compression stress, synchronously the cross-section is affected by the circumferential stress. According to the above, the distribution function and curve of tangential stress can be obtained according to force balance differential equations on circumferential direction and Trasca rule. Subsequently the real state and virtual state moment equations were established, a new method was presented adopting the virtual principle of deformation system to calculate the x-axis and y-axis displacement of arbitrary point on cross-section. So the major and minor axes of deformed cross-section can be calculated according to the displacements of each point, and the variety value of major and minor axes will be obtained further. Finally the theoretical calculating result is compared with NC tube rotary-bending experiment results to verify the rationality of theoretical analysis, and the cross-section deformation rule of thin-walled tube can be received. 展开更多
关键词 thin-walled tube stress analysis major and minor axes cross-section deformation virtual force
下载PDF
Optimizing the Qusai-static Folding and Deploying of Thin-Walled Tube Flexure Hinges with Double Slots 被引量:6
8
作者 YANG Hui DENG Zongquan +2 位作者 LIU Rongqiang WANG Yan GUO Hongwei 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第2期279-286,共8页
The thin-walled tube flexure(TWTF) hinges have important potential application value in the deployment mechanisms of satellite and solar array, but the optimal design of the TWTF hinges haven't been completely solv... The thin-walled tube flexure(TWTF) hinges have important potential application value in the deployment mechanisms of satellite and solar array, but the optimal design of the TWTF hinges haven't been completely solved, which restricts their applications. An optimal design method for the qusai-static folding and deploying of TWTF hinges with double slots is presented based on the response surface theory. Firstly, the full factorial method is employed to design of the experiments. Then, the finite element models of the TWTF hinges with double slots are constructed to simulate the qusai-static folding and deploying non-linear analysis. What's more, the mathematical model of the TWTF flexure hinge quasi-static folding and deploying properties are derived by the response surface method. Considering of small mass and high stability, the peak moment of quasi-static folding and deploying as well as the lightless are set as the objectives to get the optimal performances. The relative errors of the objectives between the optimal design results and the FE analysis results are less than 7%, which demonstrates the precision of the surrogate models. Lastly, the parameter study shows that both the slots length and the slots width both have significant effects to the peak moment of quasi-static folding and deploying of TWTF hinges with double slots. However, the maximum Mises stress of quasi-static folding is more sensitive to the slots length than the slots width. The proposed research can be applied to optimize other thin-walled flexure hinges under quasi-static folding and deploying, which is of great importance to design of flexure hinges with high stability and low stress. 展开更多
关键词 design optimization quasi-static folding and deploying flexure hinges thin-walled tube response surface method numerical simulation
下载PDF
Combined stress waves with phase transition in thin-walled tubes 被引量:5
9
作者 宋卿争 唐志平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2014年第3期285-296,共12页
The incremental constitutive relation and governing equations with combined stresses for phase transition wave propagation in a thin-walled tube are established based on the phase transition criterion considering both... The incremental constitutive relation and governing equations with combined stresses for phase transition wave propagation in a thin-walled tube are established based on the phase transition criterion considering both the hydrostatic pressure and the deviatoric stress. It is found that the centers of the initial and subsequent phase transition ellipses are shifted along the sigma-axis in the sigma tau-plane due to the tension-compression asymmetry induced by the hydrostatic pressure. The wave solution offers the 'fast' and 'slow' phase transition waves under combined longitudinal and torsional stresses in the phase transition region. The results show some new stress paths and wave structures in a thin-walled tube with phase transition, differing from those of conventional elastic-plastic materials. 展开更多
关键词 combined stress phase transition wave thin-walled tube shape memory alloy(SMA)
下载PDF
Experimental and numerical assessment of energy absorption capacity of thin-walled Al 5083 tube produced by PTCAP process 被引量:4
10
作者 A.HOSSEINI D.RAHMATABADI +1 位作者 R.HASHEMI H.AKBARI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第5期1238-1248,共11页
The energy absorption capacity of the Al5083 thin-walled tube produced by parallel tubular angular pressing(PTCAP) process was evaluated. Also, microstructure, mechanical properties, and anisotropy coefficients were s... The energy absorption capacity of the Al5083 thin-walled tube produced by parallel tubular angular pressing(PTCAP) process was evaluated. Also, microstructure, mechanical properties, and anisotropy coefficients were studied in the peripheral and axial directions. Results showed that values of energy absorption decreased with processing pass increasing and the values for the unprocessed, first and second passes were obtained to be 167, 161.4 and 160.7 J, respectively. The differences between the simulation results for the energy absorption values and their experimental values for the unprocessed, the first and the second PTCAP passes samples are about 5%, 10%, and 13%, respectively. The energy absorption capacity was related to the anisotropy coefficient and microstructure. The results demonstrated that grain refinement occurred and ultimate tensile strength(UTS) and microhardness after the first and second PTCAP passes were enhanced, while the increase rate in the first pass was much severer. Also, by applying PTCAP, the deformation modes were altered, such that the deformation mode of the annealed tube was quite symmetrical and circular while for the first and second passes there have been triple and double lobes diamond. The results of the numerical simulation for the deformation mode of the annealed and PTCAPed tubes were consistent with the experimental results. The deformation mode of tubes is dependent on their mechanical properties and variation of the mechanical properties during PTCAP process. 展开更多
关键词 energy absorption Al 5083 ultra-fine grained aluminum alloy thin-walled tube severe plastic deformation anisotropy coefficient
下载PDF
A Numerical-analytic Method for Quickly Predicting Springback of Numerical Control Bending of Thin-walled Tube 被引量:3
11
作者 Mei ZHAN He YANG Liang HUANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2006年第5期713-720,共8页
Springback is one of important factors influencing the forming quality of numerical control (NC) bending of thin-walled tube. In this paper, a numerical-analytic method for springback angle prediction of the process... Springback is one of important factors influencing the forming quality of numerical control (NC) bending of thin-walled tube. In this paper, a numerical-analytic method for springback angle prediction of the process was put forward. The method is based on springback angle model derived using analytic method and simulation results from three-dimensional (3D) rigid-plastic finite element method (FEM). The method is validated through comparison with experimental results. The features of the method are as follows: (1) The method is high in efficiency because it combines advantages of rigid-plastic FEM and analytic method. (2) The method is satisfactory in accuracy, since the field variables used in the model is resulting from 3D rigid-plastic FEM solution, and the effects both of axial force and strain neutral axis shift have been included. (3) Research on multi-factor effects can be carried out using the method due to its advantage inheriting from rigid-plastic FEM. The method described here is also of general significance to other bending processes. 展开更多
关键词 thin-walled tube Numerical control bending SPRINGBACK Numerical-analytic method 3D rigid-plastic FEM
下载PDF
Focused electron beam transport through a long narrow metal tube at elevated pressures in the forevacuum range
12
作者 Ilya BAKEEV Kirill KARPOV +2 位作者 Aleksandr KLIMOV Efim OKS Aleksey ZENIN 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第1期128-134,共7页
We present here our investigations of the features of focused electron beam transport in free space at elevated pressures of a few pascals.We have explored the effect of the beam accelerating voltage,operating gas pre... We present here our investigations of the features of focused electron beam transport in free space at elevated pressures of a few pascals.We have explored the effect of the beam accelerating voltage,operating gas pressure,and magnetic focusing upon the trajectory of beam electrons in the crossover region,in particular on the beam convergence and divergence angles.It is shown that for the forevacuum pressure range of 2-5 Pa explored,a distinctive feature of the propagation of a focused electron beam with a current of up to 20 mA at an accelerating voltage of 10-20 kV is the difference in the angles of convergence(before the focus)and divergence(after the focus).Whereas at a low pressure of 2 Pa the divergence angle is smaller than the convergence angle,as the pressure increases the divergence angle increases and for pressures greater than 5 Pa the divergence angle is greater than the convergence angle.The results obtained were used in experiments on electron beam transport through a long narrow metal tube with a diameter of 5.8-9.2 mm and length of 10-30 cm.We show that for a 30 cm long tube of 7.5 mm diameter,the focused beam transmission can exceed 70%. 展开更多
关键词 focused electron beam plasma electron source forevacuum pressure range long metal tube
下载PDF
A STUDY ON THE EFFECT OF RADIAL INERTIA ON THE ELASTO-PLASTIC COMBINED STRESS WAVE PROPAGATION IN THIN-WALLED TUBES 被引量:2
13
作者 Li Yongchi Huang Chengyi Yuan Fuping Jin Yongmei 《Acta Mechanica Solida Sinica》 SCIE EI 2001年第1期58-66,共9页
An in-depth analysis of propagation characteristics ofelasto-plastic combined stress waves in circular thin-walled tubeshas been made. In obtaining the simple-wave solution, however, mostresearches have ignored the in... An in-depth analysis of propagation characteristics ofelasto-plastic combined stress waves in circular thin-walled tubeshas been made. In obtaining the simple-wave solution, however, mostresearches have ignored the influence of the circumferential stressrelated to the radial inertial ef- fect in the tubes. In this paperthe incremental elasto-plastic constitutive relations which areconve- nient for dynamic numerical analysis are adopted, and thefinite-difference method is used to study the evolution adpropagation of elasto-plastic combined stress waves in a thin-walledtube with the radial inertial effect of the tube considered. Thecalculation results are compared with those obtained when the radialinertial effect is not considered. The calculation results show thatthe radial inertial effect of a tube has a fairly great influence onthe propagation of elasto-plastic combined stress waves. 展开更多
关键词 circular thin-walled tube elasto-plastic combined stress waves radialinertial effect
下载PDF
Torsional Behavior Design of UHPC Box Beams Based on Thin-Walled Tube Theory 被引量:6
14
作者 Imjong Kwahk Changbin Joh Jung Woo Lee 《Engineering(科研)》 2015年第3期101-114,共14页
This study proposed a prediction formula for the torsional strength enabling to reflect the tensile strength of ultra high performance concrete (UHPC) beams based upon the thin-walled tube theory. The remarkable ducti... This study proposed a prediction formula for the torsional strength enabling to reflect the tensile strength of ultra high performance concrete (UHPC) beams based upon the thin-walled tube theory. The remarkable ductile behavior of UHPC can also be attributed to the steel fiber reinforcement. This feature must be considered to provide rational explanation of the torsional behavior of UHPC structures. In this study, the proposed torsional design adopts a modified thin-walled tube theory so as to consider the tensile behavior of UHPC. And torsion test was conducted on thin-walled UHPC box beams to validate the proposed formula through comparison of the predicted torsional strength with the experimental results. The comparison of the predicted values of the cracking torque and torsional moment resistance with those observed in the torsional test of UHPC verified the validity of the design method. The contribution of the steel fibers to the torsional strength and cracking load was larger than that of the stirrups, but the stirrups appeared to contribute additionally to the torsional ductility. Accordingly, it is recommended that design should exploit effectively the contribution of the steel fiber rather than arrange a larger number of stirrups in UHPC structures subjected to torsion. 展开更多
关键词 TORSION Behavior Ultra High Performance Concrete (UHPC) thin-walled tube Torsional Strength DIAGONAL Crack
下载PDF
Viscous Inner and Outer Pressure Forming Method of Thin-walled Tube and Its Application 被引量:3
15
作者 高铁军 LIU Yang WANG Zhongjin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第2期404-407,共4页
Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large de... Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large deformation of the part into inner and outer pressure forming deformations, the limit deformation of tube part can be increased by several times. Meanwhile, the principle of viscous inner and outer pressure forming was provided, and key problems during the forming process such as reduction of the wall-thickness and instability wrinkling were analyzed. Thereby, the complex curved surface super-alloy GH3044 thin-walled tube with varying diameter ratio of 1.35(the ratio between the maximum and minimum diameters of the part) can be integrally formed by this method. The experimental surface of the formed part is superior in quality and the wall-thickness distribution is uniform. The results show that the viscous inner and outer pressure forming can provide a new approach for integral forming of thin-walled tubes with complex shapes. 展开更多
关键词 thin-walled tube inner and outer pressure forming viscous medium integral forming
下载PDF
Novel approach for analysis of deformation behavior of thin-walled tube in free hydro-bulging process
16
作者 杨连发 郭成 《中国有色金属学会会刊:英文版》 CSCD 2005年第S3期299-304,共6页
Based on the assumption that profile of thin walled tube in free hydro-bulging process is a quadratic curve and any point on the profile moves vertically to the profile, mathematical models were deduced for analyzing ... Based on the assumption that profile of thin walled tube in free hydro-bulging process is a quadratic curve and any point on the profile moves vertically to the profile, mathematical models were deduced for analyzing the deformation behavior. The critical pressure and the maximum bulge coefficient(height) at bursting can be determined based on the models, in which a shape factor a is introduced to tightly communicate the material property and geometric parameters to plastic deformation. Free hydro-bulging experiments of stainless steel and low carbon steel tubes were conducted to validate the models, and the experimental data indicate that the theoretical predictions are reliable and accurate. The results display that the profile, dependent on the material and geometric parameters, can be hyperbola, parabola, arc and ellipse or alternative among them; moreover, the forming pressure and forming limit are both closely connected with material and geometric parameters. 展开更多
关键词 hydro-bulging thin-walled tube deformation forming pressure formability
下载PDF
Evolution of Goss texture in thin-walled copper tube at different heat treatment temperatures
17
作者 Song-wei WANG Hong-wu SONG +2 位作者 Yan CHEN Qi YU Shi-hong ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第4期1205-1216,共12页
The evolution of microstructure,textures,and mechanical properties of thin-walled copper tube during heat treatment was investigated using EBSD technique and tensile test.The results show that the initial deformation ... The evolution of microstructure,textures,and mechanical properties of thin-walled copper tube during heat treatment was investigated using EBSD technique and tensile test.The results show that the initial deformation textures of pre-drawn thin-walled copper tube are mainly composed of Copper and Y components,while with the increase of temperatures,the textures are transformed into a strong Goss texture gradually.The high-resolution microstructural characterizations indicate that the new Goss recrystallized grains nucleate and grow up within the deformed Copper grains and Y grains in different mechanisms,respectively.The tensile strength of the thin-walled copper tube decreases gradually with the increase of the temperature,while the elongation increases first and then decreases sharply due to the action of grain sizes and texture components. 展开更多
关键词 thin-walled copper tube recrystallization behavior Goss texture nucleation mechanism annealing twin
下载PDF
ENERGY ABSORPTION CONTROL CHARACTERISTICS OF AL THIN-WALLED TUBES UNDER IMPACT LOAD
18
作者 Kil-Stmg Lee Yong-Jun Yang +1 位作者 Sun-Kyu Kim In-Young Yang 《Acta Mechanica Solida Sinica》 SCIE EI 2008年第4期383-388,共6页
An experimental investigation was carried out to study the energy absorption characteristics of thin-walled square tubes subjected to dynamic crushing by impact loading to develop the optimum structural members. Here,... An experimental investigation was carried out to study the energy absorption characteristics of thin-walled square tubes subjected to dynamic crushing by impact loading to develop the optimum structural members. Here, the controller is introduced to improve and control the absorbed energy of thin-walled square tubes in this paper. When the controller were used, the experimental results of crushing of square tubes controlled by the controller's elements showed a good candidate for a controllable energy absorption capability in impact crushing. 展开更多
关键词 impact load Al thin-walled tubes energy absorption controller
下载PDF
Comparison of decompression tubes with metallic stents for the management of right-sided malignant colonic obstruction 被引量:7
19
作者 Yoshiyuki Suzuki Konosuke Moritani +2 位作者 Yuki Seo Takayuki Takahashi 《World Journal of Gastroenterology》 SCIE CAS 2019年第16期1975-1985,共11页
BACKGROUND Emergency surgical resection is a standard treatment for right-sided malignant colonic obstruction; however, the procedure is associated with high rates of mortality and morbidity. Although a bridge to surg... BACKGROUND Emergency surgical resection is a standard treatment for right-sided malignant colonic obstruction; however, the procedure is associated with high rates of mortality and morbidity. Although a bridge to surgery can be created to obviate the need for emergency surgery, its effects on long-term outcomes and the most practical management strategies for right-sided malignant colonic obstruction remain unclear.AIM To determine the appropriate management approach for right-sided malignant colonic obstruction.METHODS Forty patients with right-sided malignant colonic obstruction who underwent curative resection from January 2007 to April 2017 were included in the study.We compared the perioperative and long-term outcomes of patients who received bridges to surgery established using decompression tubes and those created using self-expandable metallic stents(SEMS). The primary outcome was the overall survival duration(OS) and the secondary endpoints were the diseasefree survival(DFS) duration and the preoperative and postoperative morbidity rates. Analysis was performed on an intention-to-treat basis.RESULTS There were 21 patients in the decompression tube group and 19 in the SEMS group. There were no significant differences in the perioperative morbidity rates of the two groups. The OS rate was significantly higher in the decompression tube group than in the SEMS group(5-year OS rate; decompression tube 79.5%,SEMS 32%, P = 0.043). Multivariate analysis revealed that the bridge to surgery using a decompression tube was significantly associated with the OS(hazard ratio, 17.41; P = 0.004). The 3-year DFS rate was significantly higher in thedecompression tube group than in the SEMS group(68.9% vs 45.9%; log-rank test,P = 0.032). A propensity score–adjusted analysis also demonstrated that the prognosis was significantly better in the decompression tube group than in the SEMS group.CONCLUSION The bridge to surgery using trans-nasal and trans-anal decompression tubes for right-sided malignant colonic obstruction is safe and may improve long-term outcomes. 展开更多
关键词 Right-sided colon cancer Large BOWEL OBSTRUCTION Self-expandable metallic stent Trans-anal tube Trans-nasal tube
下载PDF
Effect of cyclotron resonance on ‘hot’ dispersion in a staggered double metallic grating sheet beam travelling wave tube 被引量:1
20
作者 Jing WANG Yu FAN +3 位作者 Chen YANG Ding ZHAO Gang WANG Jirun LUO 《Plasma Science and Technology》 SCIE EI CAS CSCD 2019年第8期89-96,共8页
Based on the beam wave synchronous interaction in transverse and longitudinal directions at the same time and starting from Maxwell’s equation and linear Vlasov equation, the beam–wave interaction ‘hot’ dispersion... Based on the beam wave synchronous interaction in transverse and longitudinal directions at the same time and starting from Maxwell’s equation and linear Vlasov equation, the beam–wave interaction ‘hot’ dispersion equation considering both cyclotron resonance and Cherenkov resonance in a staggered double metallic grating traveling wave tube is deduced.Through the reasonable selection for geometric and electrical parameters, the numerical calculation and analysis of the ‘hot’ dispersion equation shows that the beam–wave interaction gain and frequency band with the cyclotron resonance enhancement effect are higher than those with only Cherenkov resonance radiation. 展开更多
关键词 staggered DOUBLE metalLIC GRATING SHEET BEAM travelling wave tube cyclotron resonance Cherenkov effects gain
下载PDF
上一页 1 2 34 下一页 到第
使用帮助 返回顶部