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71.
钢轴心受压构件截面的直接计算法 总被引:1,自引:0,他引:1
根据钢结构设计原理,依据现行国家标准《钢结构设计规范》(GBJ17 88),通过计算构件合适长细比λ,直接进行钢轴心受压构件截面尺寸设计. 相似文献
72.
A method for the detection of small masses with the aid of a longitudinally vibrating band is described and further applications, e.g. for viscosity and humidity measurement are discussed. The complex Young's modulus of the band can also be determined. 相似文献
73.
Longitudinal wave velocity is used to characterize the point defects in crystalline solids. High purity Al single crystal was selected for both the finite element analysis and experimental work. Since the jog motions of dislocations caused by intersected slides such as cross slips induce point defects, the total amount of cross slips was calculated instead of calculating directly from the point defects. The effect of crystal orientations on total amount of cross slips under pure shear was also investigated via the finite element method. The result suggest that if the initial shear stress direction is located at the inner side of stereographic triangle, only single slip activities occurred at the beginning of plastic deformation and no effects due to point defects were present. However, as the shear stress direction rotates along the slip direction, point defects are induced by cross slips between primary and secondary slip systems due to work-hardening. This phenomenon was then examined by measuring longitudinal wave velocity changes propagating in Al single crystal subjected to the combination loads of equi-biaxial tension and compression (a pure shear state). Good qualitative agreement between the finite element result and measured data suggest that the longitudinal wave velocity can be used as an index to characterize point defects in crystalline materials. 相似文献
74.
An investigation of meterial properties of non-homogeneous cylindrically orthotropic circular plates
It has been been reported that the reduced stiffness of non-homogeneous cylindricallyorthotrpic circular plate varing exponentially with radius r is obtained by using thebending theory of a simple beamThe aim of this paper is to verify the effect of radius on the materal properties According to the flat stress-strain relation the values of material properties Er Ea and vθr which are the functions of radius r are obtained.Compared with the experimentalvalues the analytical values of the material properties are in essential agreement withtem. 相似文献
75.
腐蚀磨损协同作用率的研究 总被引:7,自引:5,他引:7
提出了腐蚀与磨损“协同作用”的概念,并用于判断腐蚀与磨损协同作用的性质及大小和确定腐蚀磨损过程中材料损失的主要形式。介绍了协同作用率的测定方法,并以G105钢及化学镀Ni-P合金在5.0%NaCl溶液中的腐蚀腐损作为研究对象,研究了载荷、滑动速度对腐蚀磨损协同作用的影响。结果表明:协同作用率随载荷增大而增大,随滑动速度增大而减小。 相似文献
76.
77.
李萨如图形在检测系统中的应用 总被引:5,自引:0,他引:5
李萨如图形可以检测两个相同频率信号的相位差.主要论述具有惯性质量、弹簧和阻尼器的二阶加速度测量系统,其动态响应特性的分析方法,如何利用李萨如图形来检测力平衡式加速度传感器的动态特性,即幅频特性和相频特性,从而确定传感器的固有频率ω_n和阻尼比ξ,以此来评定传感器的综合特性. 相似文献
78.
79.
New fabrication technologies now allow for hybrid sandwich structures, known as X-core, to be manufactured. The X-core panels
consist of a pin reinforced polymer foam core with carbon fiber face sheets. Carbon fiber or metallic (Titanium/Steel) pins
are inserted into the foam core in the out-of-plane direction and extend from face sheet to face sheet. The through thickness
three-point simply supported bending behavior of these panels is used to evaluate the collapse characteristics of the panels.
Explicit experimental observations are used to calibrate analytical energy balance models describing the panel collapse as
a function of geometry and properties. The mechanical response of X-core sandwich panels is compared to current sandwich materials
for material selection. 相似文献
80.
Fracture of a rectangular piezoelectromagnetic body 总被引:5,自引:0,他引:5
The singular stress, electric fields and magnetic fields in a rectangular piezoelectromagnetic body containing a center Griffith crack under longitudinal shear are obtained. Fourier transforms and Fourier sine series are used to reduce the mixed boundary value problems of the crack, which is assumed to be impermeable, to dual integral equations. The solution of the dual integral equations is then expressed in terms of Fredholm integral equations of the second kind. Expressions for stresses, electric displacements and magnetic inductions in the vicinity of the crack tip are derived. Also obtained are the field intensity factors and the energy release rates. Numerical results obtained show that the geometry of the rectangular body have significant influence on the field intensity factors and the energy release rates. 相似文献