全文获取类型
收费全文 | 295篇 |
免费 | 0篇 |
专业分类
公路运输 | 81篇 |
综合类 | 52篇 |
水路运输 | 98篇 |
铁路运输 | 47篇 |
综合运输 | 17篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 17篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 10篇 |
2016年 | 12篇 |
2015年 | 17篇 |
2014年 | 22篇 |
2013年 | 13篇 |
2012年 | 20篇 |
2011年 | 23篇 |
2010年 | 16篇 |
2009年 | 15篇 |
2008年 | 12篇 |
2007年 | 19篇 |
2006年 | 21篇 |
2005年 | 9篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1992年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有295条查询结果,搜索用时 109 毫秒
51.
52.
53.
It has been reported that low transformation temperature (LTT) weld metals are beneficial to generation of compressive residual stress around weld zone. In this study, the relationship among residual stress, size effect of LTT welded joints with different plate width and thickness as well as martensite start (Ms) temperatures was investigated by experimental and finite-element analysis. It was found that heat dissipation and thermal expansion coefficient of LTT weld metal had a significant impact on residual stress. Welded joint with a small plate width led to greater compressive residual stresses in the LTT weld, which was due to the lower heat dissipation and smaller thermal expansion coefficient of the LTT weld metal in due course of cooling process. Additionally, the finite-element analysis revealed that increasing plate width mainly affected the longitudinal residual stress, while increasing the plate thickness influenced all the residual stress components in the LTT weld. Furthermore, the LTT weld with a lower Ms temperature of 191 °C resulted in greater compressive residual stresses, and was less sensitive to the LTT joint size, as against the Ms temperature of 398 °C. 相似文献
54.
In this study, a new one-way integrated numerical model for fluid–seabed–structure interaction is established by integrating the finite element software, ABAQUS, and the open-source fluid dynamics package, OlaFlow. In this new model, the generation and propagation of ocean waves as well as the seepage flow in a porous medium are controlled by OlaFlow; concurrently, the wave-induced dynamic responses of a porous seabed and marine structures are governed by ABAQUS. The reliability of this new model is validated by an analytical solution and a series of wave flume tests. The comparison results show that the new established model has high reliability and feasibility. Finally, this new integrated model is utilized for investigating the wave-induced dynamics of a composite breakwater and its seabed foundation as well as to evaluate the residual horizontal sliding displacement of the caisson of this composite breakwater under wave impact. Because this new integrated numerical model can fully utilize the advantages of both ABAQUS and OlaFlow, it is expected to have broad prospects for application in engineering practice. 相似文献
55.
Nonlinear behavior of jacket platforms is important in both design and rehabilitation issues that depends on the bracing arrangement. Both ductility and strength of the structures derived from pushover analysis are highly related to configuration of the braces. Considering a suitable criterion such as constant weight or constant stiffness and period of the structure in all arrangement cases, one can compare the capacity curves and find the best configuration. In this paper a simple logical method for investigating the strength and ductility of the jacket structure is presented, it is shown that global geometry and configuration of the braces are very important and effective in both strength and ductility parameters. Three parameters, normalized strength, normalized ductility and a combination of these two parameters are defined in order to have an engineering and practical index for comparing the results. At the end of the numerical discussion, the optimum configuration can be found. Such an investigation is very important in the initial design stage. Also, in assessment of existing platforms, it is very important to find the reliable strength and ductility of the structure. Such a study gives a deep view of this issue as well. 相似文献
56.
Existing rule scantling formulae of plate members are based on conventional plastic design theory, and do not necessarily reflect complicated plate bending phenomena under axial loads. In this study, we first formulated the effect of axial load on the fully plastic moment based on the von Mises yield criterion for longitudinally stiffened plate in addition to the well-known formula for transversely stiffened plate. In addition, we derived a theoretical formulation of the lateral pressure corresponding to 2-point hinge and 3-point hinge formation taking account of the effect of the additional lateral force due to the axial loads on the deflected plating, using a simple plate strip bending model assuming a long plate with a large aspect ratio.Then, a series of elastic-plastic FE analyses was carried out to verify the structural behavior and the effect of axial load on the plate plastic bending strength. The plate strength was evaluated based on the residual deflection criteria of two cases (0.26 mm and 4.0 mm), and the results were compared with the theoretical derivation. As a result, it was found that assumption of linear strength reduction to the axial stress can cover the transversely stiffened plate under compressive axial stress conservatively. As to the transversely stiffened plate under tensile axial stress and the longitudinally stiffened plate, the strength reduction was in accordance with the reduction in the fully plastic moment based on the von Mises yield criterion in the conservative side. Finally, based on the findings, the required plate thickness coefficients were proposed on an empirical basis both for transversely and longitudinally stiffened plate under compressive and tensile axial loads. 相似文献
57.
58.
In support of the development of improved fillet weld sizing criteria for lightweight shipboard structures, a comprehensive static strength test program using longitudinal and transverse shear specimens according to AWS B4.0 Standards has been conducted. This test program covers base material with strength ranging from 71 ksi (490 MPa) to 96 ksi (660 MPa) and weld size ranging from 1/8″ (3 mm) to 3/8″ (10 mm). This paper focuses on a traction stress based analysis of the test data as an effort to establish a unified shear strength definition for load-carrying fillet weld specimens regardless of shear loading conditions. The proposed shear strength definition proves to be effective in correlating the fillet weld strength test data of the longitudinal and transverse shear specimens. The results of this investigation demonstrate that existing shear strength definitions used by various weld sizing criteria such as those given by Class Societies have two major limitations: (1) it cannot be related to a critical stress state on experimentally observed failure plane in transverse shear specimens; (2) it underestimates shear stress at failure due to severe stress concentration at weld end in typical longitudinal shear specimens. These two limitations have been shown to be the major cause for having two significantly different shear strength values: one is transverse shear strength obtained from transverse shear specimens and the other is longitudinal shear strength obtained from longitudinal shear specimens. 相似文献
59.
在煤炭漏斗车标准和设计技术条件中均未规定隔板强度,漏斗车车体设计静强度计算中,未施加相应载荷进行设计验证。同时,某型号煤炭漏斗车在应用中出现隔板裂纹。为此,基于离散元-有限元(DEM-FEM)结合的方法,模拟煤炭漏斗车装卸煤炭过程,分析煤炭漏斗车车体隔板受力和强度仿真计算结果,并与煤炭漏斗车车体隔板现场测试强度结果进行对比。结果表明:装载煤炭过程中,隔板所受最大载荷大约为稳定时载荷的1.8倍;卸载煤炭过程受不同底门开启的影响,隔板所受载荷瞬间突增80%~112.6%。装卸过程中隔板所受作用力与高度之间呈非线性分布,仿真计算结果与现场测试数据基本吻合。这为设计煤炭漏斗车车体隔板时提供参考。 相似文献
60.
深水S型铺管托管架结构的非参数化敏感性分析 总被引:1,自引:1,他引:0
托管架是铺管作业的大型设备,其安全性对作业安全极为重要。针对托管架结构损伤实时监测这一目标,对深水作业状态的托管架结构进行整体和局部刚度校核、强度校核,并用设计波法校核了深海铺管作业的稳定性,在上述所得托管架结构的基本力学数据基础上,对托管架的构件进行了整体变形、局部变形、整体应力分布、疲劳易发点应力水平、关键连接杆应力水平和主弦杆多杆交汇处应力水平的敏感性分析,找出了托管架结构的关键构件,作为实时监测的测量点,为结构损伤实时监测做出了至关重要的准备性工作。 相似文献