共查询到20条相似文献，搜索用时 46 毫秒
1.
In this paper, based on the theory of the rotation of a cross section around a fixed axis, a new calculation method of second-order stress of space stability for thin wall member is applied. The example given in this paper shows that the conception of this new method of second order analysis is clear and the calculation procedure is concise. 相似文献
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Zhou Shizhen 《保鲜与加工》1996,(2):61-76
In this paper, ultimate loading capacity of eccentric compressed timber column and elastic-plastic behaviour of the material of the cross section are considered.An approximate theoretic method dealing with the maximum mid-span deflection of the column when breaking is advanced.As a result, a formula calculating failure deflection of the rectangular cross section is derived. The results of theoretic calculation are well coincident with those of tests. 相似文献
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种植密度对夏玉米穗位叶片解剖结构的影响 总被引：2，自引：0，他引：2
为了研究种植密度对玉米穗位叶片解剖结构的影响, 以生产上广泛种植的玉米杂交种郑单958和浚单20为材料,采用石蜡制片和超薄切片法对不同种植密度下2个玉米品种穗位叶片和叶绿体的结构进行了观察分析。结果表明, 随着种植密度的增加,2个玉米品种的叶片厚度、叶脉横截面积和叶脉木质部面积减小,上、下表皮的气孔频度减少(郑单958显著,浚单20不显著),叶肉细胞叶绿体的基粒数量减少,维管束鞘细胞叶绿体的数量减少;种植密度在75 000株 hm-2时产量最高。相关性分析显示,叶脉木质部面积、气孔频度、叶肉细胞叶绿体的基粒数量、叶肉细胞叶绿体的基粒数量与种植密度呈显著负相关,与单穗籽干重、千粒重、穗粒数量呈显著正相关,因而成为玉米生产上的重要结构指标。 相似文献
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According to the field theory of additional deformation on pre - stressed configuration , in the paper , the ordinary expression of the governing equation and variational equation of elastic buckling are brought forward . Under the theory system, through lowering dimensions, the governing equation and variational equation for the critical condition solution of elastic buckling of a plane arch are deduced, and the eigenvalues problem of the linear homogeneous differential equations corresponding to the equations are concluded While Abandoning the plane assumption and considering shearing deformation, the linear finite element method arithmetic of bending bar's cross section containing six degree of freedom is given. The process of derivation and calculational results show that, under this system info, the finite element equations of bending bar deduced are accurate and easy to be used to numeric calculations, and the conclusion achieved is more practical. 相似文献
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采用简化的纤维增强混凝土应力应变关系,根据截面变形的平截面假定和截面力的平衡方程,推导出塑性铰区采用纤维增强混凝土柱在不同极限状态时的曲率。根据各极限状态点曲率,求得截面上各分布力,对截面形心轴取距,到塑性铰区采用FRC柱的开裂、屈服、峰值和极限点的弯矩表达式。与试验结果对比表明,计算值与试验值吻合较好。 相似文献
6.
Liao Shujiang Lu Xiaofeng 《保鲜与加工》1998,(4):111-116
The influence of the arrangements of pipes on gas solid flow characteristics in the dense section of standpipe in the circulating fluidized bed is studied on a cold state experiment platform.The influence relationships of the percentage of area of pipes in the standpipe cross section and section shape of pipes and the circulation rate,adjusting range and distribution percentage of loose air are studied emphasizedly. 相似文献
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The span ratio and the ratio of section height to section thickness of column leg are selected, which mainly influence the shear effect of special shaped columns. Based on error analysis of the displacement at the tip of the columns, the flexibility of a fiber model for L shaped columns, T shaped columns, and cross shaped columns in the range of elasticity is studied. The columns are studied with and without shear effect. The correctness of the fiber model with the shear effect is shown, and the applicable range of the fiber model with the shear effect is presented. 相似文献
9.
The authors calculate the cross-section with one-loop electroweak corrections to electron-positron pair production via two photon collisions in the standard model (SM), including virtual corrections and soft photon radiative correction. The relations between the cross-sections are discussed in tree level (and one-loop corrected cross sections) and center-mass energy in the luminosity measuring ranges of GLC. At last, the authors acquire the relation curves between differential cross section and the outgoing electron angle. 相似文献
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Natural coordinate system along the axis of a curved -rod is used to describe the static problems in small deformation, and virtual work equation is in turn utilized to derive the geometric equations of the problems. The general solution of internal forces and general displacements in the matrix form with 6 integral constants are given out, without the assumption of plane cross - section. 相似文献
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According to the theory of thin-walled bar with closed section,a combined mod-el is esta blished of coupling deformation,and an accurate method of analysing stresses between lay-ers is suggested. With the medel,the analyses results were offered to sandwich bar with box section. 相似文献
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Directing toward the flow design of cantilever anti slide piles, the thesis which is based on foundation coefficient method and finite element method mainly analyzes service behavior influences by changing several design parameters, such as cross section 相似文献
16.
Considering the large negative bending moment at the end of frame beam and low tensile strength of concrete,a new composite steel-concrete frame beam(CSCFB),reinforced by a T shape steel beam at the negative bending regions,was brought forward.Through two full-scale of single-layer CSCFB frame models experiment,the load-displacement curves of CSCFB and strain distribution at cross section were obtained.Compared with the ordinary composite beam,the T shape reinforcing section can enhance the beam stiffness effectively,and make it distribute reasonably.The segment flexural rigidity method is presented and validated. 相似文献
17.
Xiao Dichen Liang Xichang 《保鲜与加工》1990,(1):13-22
In this paper, a calculation method of forming cutter contour of involute helical with arbitrary easement is presented, the segmantal arcs of the best uniform approximation and tolerance to fit smoothly the cutter contour points are used the profile on the cross section of the helical is calculated and the design of the cutter is examined. The method can be used to design precision forming cutter of involute helical with the arbitrary easement. It is valuable in engineering application. 相似文献
18.
Simplified Calculation on Across-Wind Response of Tapered High-rise Structures with Circular Section
Now it is complex to calculate across-wind response of tapered high-rise structures with circular section abroad and its research at home is inadequate.Based on random vibration theory and across-wind force spectrum proposed by B.J.Vickery,a simplified formula on maximum across-wind response of tapered high-rise structures with circular section is achieved in this paper.With respect to engineering calculation,the results obtained by simplified method corresponds with those obtained by standard method based on the theory of random vibration well,but the prediction values by approximate method proposed by B.J.Vickery are smaller. 相似文献
19.
Adopting the element SOLID65 and LINK8 in the general finite element analysis software ANSYS and fiber model beam-column element based on finite element flexibility method respectively, the comparative analysis of the cross, L and T-shaped RC columns under compression, bending, shear and torsion with flange width-thickness ratio of 4:1 is carried out. The applicability of plane section assumption in the nonlinear analysis is discussed primarily, which shows that it is feasible on the whole for shaped RC columns with flange width-thickness ratio equal to or smaller than 4:1. 相似文献
20.
Distribution Characteristics and Prediction of Equilibrium Moisture of Non saturated Clay Subgrade 总被引：1，自引：0，他引：1
The space distribution characteristics of equilibrium moisture of non saturated clay subgrade were surveyed along the road cross section by the in situ and laboratory tests. Based on the basic theory of unsaturated soil mechanics, matric suctions of soil samples with different kinds of moisture condition were determined and the soil water characteristic curve model was calibrated to reflect a single valued function relationship between water content and matric suction of clay soils. Combining the above results, an estimation method of the equilibrium moisture of the unsaturated clay subgrade outside the affected zone of atmospheric precipitation/evaporation was established. The results show that the atmospheric precipitation/evaporation has significant effect on moisture condition of the subgrade soil located in the upper part of the subgrade near the central reserve and hard shoulders. However, equilibrium moisture of subgrade soil outside the affected zone of atmospheric precipitation/evaporation is mainly controlled by the impact of the groundwater table. Fredlund & Xing model can be used to characterize the relationship between the unsaturated clay soil moisture and matric suction, and the fitting results of model parameters have high reliability. A consistency between the predictive results and the experimental data shows the presented model is accurate and credible. 相似文献