共查询到20条相似文献，搜索用时 31 毫秒
1.
In order to constitute engineering design methods of the flat ribbon wound explosion containment vessels, the dynamic response of such vessels subjected to internal explosion loading is simulated using LS-DYNA3D. Three winding angles, 10°, 15°and 20°, are considered. It is shown that among ribbon vessels investigated, the center displacement of outermost ribbons of the vessel with 10°winding angle is the smallest under the same blast loading. The response of vessels loaded in inner core is local. From the center of the cylindrical shell to the bottom cover, the maximum strain gradually decreases. The ribbons are subjected to tension in the length direction and compression in the width direction. Blasting shock energy concentrates on where is close to center section of blasting. For comparison, numerical simulation of a monobloc thick-walled explosion containment vessel is also investigated. It can be found that the biggest deformation of the flat ribbon wound explosion containment vessels is bigger than that of the monobloc thick-walled explosion containment vessel in the center section of blasting under the same TNT. Numerical results are approximately in agreement with experimental ones. It is proved that the ribbon vessels have the valuable properties of " leak before burst at worst" compared with the monobloc vessels through numerical simulation. 相似文献
2.
The dynamic characteristics and failure modes of steel reinforced concrete (SRC) columns subjected to blast loading are complicated because of the transient stress wave in the SRC columns and the interaction between steel and concrete. This paper presents a numerical simulation of the response of SRC columns subjected to blast loading using hydrocode LS-DYNA. In the numerical model, a sophisticate concrete material model (the Concrete Damage Model) is employed with consideration of the strain rate effect and the damage accumulation. An erosion technique is adopted to model the spalling process of concrete. The possible failure modes of SRC columns are evaluated. It is observed that the failure of SRC columns subjected to blast load can generally be classified into three modes, namely, a direct failure in concrete body due to the stress wave, a transverse shear failure near the support sections due to the high shear force, and a flexural failure pertaining to large local and global deformation of the reinforcing steel. 相似文献
3.
In Order to reduce economic and life losses due to terrorism or accidental explosion threats,reinforced concrete(RC)slabs of buildings need to be designed or retrofitted to resist blast loading.In this paper the dynamic behavior Of RC slabs under blast loading and its influencing factors are studied.The numerical model of an RC slab subjected to blast loading is established using the explicit dynamic analysis software.Both the strain rate effect and the damage accumulation are taken into account in the material model.The dynamic responses of the RC slab subiected to blast loading are analyzed,and the influence of concrete strength,thickness and reinforcement ratio on the behavior of the RC slab under blast loading iS numerically investigated.Based on the numerical results.some principles for blast-resistant design and retrofitting are proposed to improve the behavior of the RC slab subjected to blast loading. 相似文献
4.
Current practice in analysis and design of blast doors subjected to blast loading considers only simple boundary conditions and material properties. The boundary conditions and material properties, in fact, have considerable influence on the response of blast doors subjected to blast loading. In this paper, the dynamic responses of a reinforced concrete arched blast door under blast loading were analyzed by the finite element program ABAQUS, combined with a previously developed elasto-viscoplastic rate-sensitive material model. And the effect of the surrounding rock mass and contact effect of the doorframe were also taken into account in the simulation. It is demonstrated that the strain-rate effect has considerable influence on the response of reinforced concrete blast door subjected to blast loading and must be taken into account in the analysis. 相似文献
5.
In the present paper, a dynamic plastic damage model for concrete has been employed to estimate responses of a reinforced concrete slab subjected to blast loading. The interaction between the blast wave and the concrete slab is considered in 3D simulation. In the first stage, the initial detonation and blast wave propagation is modelled in 2D simulation before the blast wave reaches the concrete slab, then the results obtained from 2D calculation are remapped to a 3D model. The calculated blast load is compared with that obtained from TM5-1300. Numerical results of the concrete slab response are compared with the explosive test carried out- in the Weapons System Division, Defence Science and Technology Organisation, Department of Defence, Australia. 相似文献
6.
ZHOU Xiaoqing HAO Hong KUZNETSOV Valerian A WASCHL John 《天津大学学报(英文版)》2006,12(B09):94-99
In the present paper, a dynamic plastic damage model for concrete has been employed to estimate responses of a reinforced concrete slab subjected to blast loading. The interaction between the blast wave and the concrete slab is considered in 3D simulation. In the first stage, the initial detonation and blast wave propagation is modelled in 2D simulation before the blast wave reaches the concrete slab, then the results obtained from 2D calculation are remapped to a 3D model. The calculated blast load is compared with that obtained from TM5-1300. Numerical results of the concrete slab response are compared with the explosive test carried out-in the Weapons System Division, Defence Science and Technology Organisation, Department of Defence, Australia. 相似文献
7.
GONG Shunfeng LU Yong GAO Feng JIN Weiliang 《天津大学学报(英文版)》2006,12(B09):248-253
For a building structure subjected to impulsive loading, particularly shock and impact loading, the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading phase. Therefore, an appropriate evaluation of the column response and damage under short-duration impulsive loading is important in a comprehensive assessment of the performance of a building system. This paper reports a dynamic analysis approach for the response of RC columns subjected to impulsive loading. Considering that the dynamic response of a column in a frame structure can also be affected by the floor movement which relates to the global vibration of the frame system, a generic column-mass model is used, in which a concentrated mass is attached to the column top to simulate the effect of a global vibration. To take into account the high shear effect under impulsive load, the model is formulated using Timoshenko beam theory, and three main nonlinear mechanisms are considered. Two typical scenarios, one under a direct air blast loading, and another under a blast-induced ground excitation, are analyzed and the primary response features are highlighted. 相似文献
8.
For a building structure subjected to impulsive loading, particularly shock and impact loading , the response of the critical columns is crucial to the behaviour of the entire system during and after the blast loading phase. Therefore, an appropriate evaluation of the column response and damage under short-duration impulsive loading is important in a comprehensive assessment of the performance of a building system. This paper reports a dynamic analysis approach for the response of RC columns subjected to impulsive loading. Considering that the dynamic response of a column in a frame structure can also be affected by the floor movement which relates to the global vibration of the frame system, a generic column-mass model is used, in which a concentrated mass is attached to the column top to simulate the effect of a global vibration. To take into account the high shear effect under impulsive load, the model is formulated using Timoshenko beam theory, and three main nonlinear mechanisms are considered. Two typical scenarios, one under a direct air blast loading, and another under a blast-induced ground excitation, are analyzed and the primary response features are highlighted. 相似文献
9.
LI Q M 《天津大学学报(英文版)》2006,12(Z1)
In order to ensure the highest safety requirements, nuclear power plant structures (the containment structures, the fuel storages and transportation systems) should be assessed against all possible internal and external impact threats. The internal impact threats include kinetic missiles generated by the failure of high pressure vessels and pipes, the failure of high speed rotating machineries and accidental drops. The external impact threats may come from airborne missiles, aircraft impact, explosion blast and fragments. The impact effects of these threats on concrete and steel structures in a nuclear power plant are discussed. Methods and procedures for the impact assessment of nuclear power plants are introduced. Recent studies on penetration and perforation mechanics as well as progresses on dynamic properties of concrete-like materials are presented to increase the understanding of the impact effects on concrete containment structures. 相似文献
10.
The soil-structure interaction (SSI) decoupling is applied to simplify buried structure against internal blast load as spring effect. Shear failure, bending failure and combined failure modes are considered based on five transverse velocity profiles for the rigid-plastic structural element. The critical equations for shear and bending failure are derived respectively. Pressureimpulse diagrams are accordingly developed to assess damage of the buried structures against internal blast load. Comparison is done to show influences of soil-structure interaction and shear-to-bending strength ratio of a structural element. A case study is conducted to show the application of damage assessment to a reinforced concrete beam element of buried structure. 相似文献
11.
Pressure pipes are widely used in modern industry with some in potentially dangerous situations of explosion and impact. The security problems of these pipes when subjected to impact have attracted a lot of attention. A non-linear numerical model has therefore been developed to investigate the dynamic behavior of pressure pipes subjected to high-velocity impact. A high strain rate effect on the pipe response is considered here and the fluid and pipe interaction is modeled to include the coupling effect between the deformation of the pipe and its internal pressure. Low-velocity and high-velocity impact experimental results are used to verify the numerical model, and a reasonable agreement between the numerical and experimental results has been achieved. The effects on the dynamic behavior of the pipes of the nose shape of the projectile, the diameter of the spherical projectile, and the pipe wall thickness and internal pressure, are investigated quantitatively. During high-velocity impacts, the increase of pressure in the pipes decreases their resistance to perforation. A rise in internal pressure increases the elastic resistance of the pipes toward impacts without crack formation. 相似文献
12.
In order to design and retrofit a subway station to resist an internal blast,the distribution of blast loading and its effects on structures should be investigated firstly.In this paper,the behavior of a typical subway station subjected to different internal blast Ioadings was analyzed.It briefly introduced the geometric characteristics and material constitutive model of an existing two-layer and three-span frame subway station.Then three cases of different explosive charges were considered to analyze the dynamic responses of the structure.Finally,the maximum principal stress,displacement and velocity of the columns in the three cases were obtained and discussed.It concluded that the responses of the columns are sensitive to the charge of explosive and the distance from the detonation.It's also found that the stairs between the two layers have significant effects on the distribution of the maximum principal stress of the columns in the upper layer.The explicit dynamic nonlinear finite element software-ANSYS/LS-DYNA was used in this study. 相似文献
13.
Current guidelines recommend using single-degree-of-freedom(SDOF) method for dynamic analysis of reinforced concretec (RC) structures against blast loads, which is not suitable for retrofitted members. Thus, a finite difference procedure developed in another study was used to accurately and efficiently analyze the dynamic response of fibre reinforced polymer (FRP) plated members under blast loads. It can accommodate changes in the mechanical properties of a member's cross section along its length and through its depth in each time step, making it possible to directly incorporate both strain rate effects (which will vary along the length and depth of a member) and non-uniform member loading to solve the partial differential equation of motion. The accuracy of the proposed method was validated in part using data from field blast testing. The finite difference procedure is implemented easily and enables accurate predictions of FRP-plated-member response. 相似文献
14.
在冲击荷载作用下,钢框架结构的动态响应是一个复杂的非线性过程。运用ANSYS/LS-DYNA建立了钢框架的三维模型,对冲击荷载作用下钢框架的动态响应和破坏形态进行研究。采取多点积分算法,有效避免沙漏问题,保证计算结果精确。以冲击块与钢框架的碰撞冲击为例,研究了冲击速度、冲击块质量、冲击位置等参数对钢框架在横向冲击作用下动力响应的影响,并分析冲击荷载下钢框架的破坏形态。结果表明:冲击块的质量、速度、冲击位置的增加都会不同程度地加剧钢框架的动态响应;在冲击作用下,高应变主要出现在被冲击柱子的冲击区域、柱脚处和梁柱节点处;冲击荷载下钢框架的破坏形态为整个框架发生侧移,受冲击柱在冲击处翼缘出现局部屈曲,受冲击区域的截面发生弯扭,未受冲击柱出现倾斜。 相似文献
15.
Dong-ming Yan Hua-wei Yin Cheng-lin Wu Yan-long Li Jason Baird Gen-da Chen 《浙江大学学报(A卷英文版)》2016,17(9):689-701
In this study, two full-size concrete walls were tested and analyzed to demonstrate the effectiveness of a chemically reactive enamel (CRE) coating in improving their mechanical behavior under blast loading: one with CRE-coated rebar and the other with uncoated rebar. Each wall was subjected in sequence to four explosive loads with equivalent 2, 4, 6-trinitrotoluene (TNT) charge weights of 1.82, 4.54, 13.6, and 20.4 kg. A finite element model of each wall under a close-in blast load was developed and validated with pressure and strain measurements, and used to predict rebar stresses and concrete surface strain distributions of the wall. The test results and visual inspections consistently indicated that, compared with the barrier wall with uncoated reinforcement, the wall with CRE-coated rebar has fewer concrete cracks on the front and back faces, more effective stress transfers from concrete to steel rebar, and stronger connections with its concrete base. The concrete surface strain distributions predicted by the model under various loading conditions are in good agreement with the crack patterns observed during the tests. 相似文献
16.
Cun-jian MIAO Jin-yang ZHENG Xiao-zhe GAO Ze HUANG A-bin GUO Du-yi YE Li MA 《浙江大学学报(A卷英文版)》2013,14(1):31-37
Cold-stretched pressure vessels from austenitic stainless steels(ASS) are widely used for storage and transportation of liquefied gases,and have such advantages as thin wall and light weight.Fatigue is an important concern in these pressure vessels,which are subjected to alternative loads.Even though several codes and standards have guidelines on these pressure vessels,there are no relevant design methods on fatigue failure.To understand the fatigue properties of ASS 1.4301(equivalents include UNS S30400 and AISI 304) in solution-annealed(SA) and cold-stretched conditions(9% strain level) and the response of fatigue properties to cold stretching(CS),low-cycle fatigue(LCF) tests were performed at room temperature,with total strain amplitudes ranging from -.4% to -.8%.Martensite transformations were measured during the tests.Comparisons on cyclic stress response,cyclic stress-strain behavior,and fatigue life were carried out between SA and CS materials.Results show that CS reduces the initial hardening stage,but prolongs the softening period in the cyclic stress response.Martensite transformation helps form a stable regime and subsequent secondary hardening.The stresses of monotonic and cyclic stress-strain curves are improved by CS,which leads to a lower plastic strain and a much higher elastic strain.The fatigue resistance of the CS material is better than that of the SA material,which is approximately 1?03 to 2?04 cycles.The S-N curve of the ASME standard for ASS is compared with the fatigue data and is justified to be suitable for the fatigue design of cold-stretched pressure vessels.However,considering the CS material has a better fatigue resistance,the S-N curve will be more conservative.The present study would be helpful in making full use of the advantages of CS to develop a new S-N curve for fatigue design of cold-stretched pressure vessels. 相似文献
17.
STEWART Mark G 《天津大学学报(英文版)》2006,12(Z1)
A probabilistic risk assessment procedure is developed which can predict risks of explosive blast damage to built infrastructure, and when combined with life-cycle cost analysis, the procedure can be used to optimise blast mitigation strategies. The paper focuses on window glazing since this is a load-capacity system which, when subjected to blast loading, has caused significant damage and injury to building occupants. Structural reliability techniques are used to derive blast reliability curves for annealed and toughened glazing subjected to explosive blast for a variety of threat scenarios. The probabilistic analyses include the uncertainties associated with blast modelling, glazing response and glazing failure criteria. Damage risks are calculated for an individual window and for windows in the facade of a multi-storey commercial building. The paper shows an illustrative example of how this information, when combined with risk-based decision-making criteria, can be used to optimise blast mitigation strategies. 相似文献
18.
STEWART Mark G 《天津大学学报(英文版)》2006,12(B09):8-15
A probabilistic risk assessment procedure is developed which can predict risks of explosive blast damage to built infrastructure, and when combined with life-cycle cost analysis, the procedure can be used to optimise blast mitigation strategies. The paper focuses on window glazing since this is a load-capacity system which, when subjected to blast loading, has caused significant damage and injury to building occupants. Structural reliability techniques are used to derive blast reliability curves for annealed and toughened glazing subjected to explosive blast for a variety of threat scenarios. The probabilistic analyses include the uncertainties associated with blast modelling, glazing response and glazing failure criteria. Damage risks are calculated for an individual window and for windows in the facade of a multi-storey commercial building. The paper shows an illustrative example of how this information, when combined with risk-based decision-making criteria, can be used to optimise blast mitigation strategies. 相似文献
19.
根据不同振幅动荷载的三组蠕变试验结果,比较了冻结粉土在不同动荷载作用下的蠕变变形和动蠕变强度特征,发现,当动荷载振动幅值不同时,动蠕变曲线变化规律以及动蠕变强度特征变化规律都相似,但数值上有较大差别;在相同静荷载基础上叠加不同振幅动荷载时,在整个蠕变过程中,振幅越大,变形越大。而对于卸载到零的动荷载试验来说,初始蠕变阶段和稳定蠕变阶段的变形较小,但由于蠕变速率很大,变形迅速增加,很快进入渐进流阶段,随后变形变得很大;冻土的动蠕变强度随时间有规律地衰减;动荷载的振幅越大,破坏时间越短,土体越容易发生破坏。 相似文献
20.
周家泽 《武汉职业技术学院学报》2003,2(2):43-45
讨论了随机荷载特性与结构弹塑性极限分析的基本假设，基于机动法和静力法，对矩形截面梁的随机弹塑性极限分析进行了研究，其结果对结构随机优化设计具有重要意义。 相似文献