共查询到20条相似文献,搜索用时 15 毫秒
1.
It is necessary to input the hourly meteorological data in order to analyze building annual energy consumption and to simulate dynamically air-conditioning systems.The hourly outdoor temperature constituted by cubic splineinterpolation when forming meteorological data is used for building energy anal-ysis.This paper analyzes the theory of spline function interpolation errors affe-cted by boundary conditions and introduces the methods to decrease interpolationerror. 相似文献
2.
Yang Youkui Wu Gang Qiu Xiande Xiao Changfu 《保鲜与加工》1992,(2):1-6
Based on the discussion of the phenomenon that the effect of fracture toughness is neglected in general hydraulic fracturing models, this paper gives the energy balance equation in-colding all parameters in hydraulic fracturing and proposes a method of determining the apparent fracture toughness of rock from hydraulic fracture experimental data. The discussion on the factors affecting apparent toughness indicates the inevitability that the apparent fracture toughness of rock measured by hydraulic fracture experimental data is significantly higher than that measured by the standard three-point bending method. 相似文献
3.
He Zefu Wu Yunjian 《保鲜与加工》1988,(4)
The effect of small amounts of gallium on the intergranular segregation of phosphorus in carbon steels is discussed, with the help of the impact test, fracture morphology and micro-structure analyses, combined with composition analysis on the fracture surfaces by Auger electronspectrometer. The results show that gallium in the steel with a content of gallium more than ten thou-sandth can suppress, to some extent, the intergranular segregation of phosphorus and retard the tempering process. As a result, the temper embrittlement of the steel disappears and the embrittlement transition temperature declines. 相似文献
4.
This paper is about the fracture tests for rocks performed under the stress of compression and shear. The characteristics of cornpre-ssive and shear fracture for rocks are described. The compress shear fracuure criteria of rocks are obtained. 相似文献
5.
Yang Youkui Qiu Xiande Zhang Zhicheng 《保鲜与加工》1990,(5):68-74
Based on the blasting theory and "Fracture Mechanics " , the directing effect mechanism of V-netch in V-rotching blasting is studied and the positive splitting and directional explanding of crack within V-notching blasting and the priority of crack's expanding in the V-notch axle-plane etc are expounded. It's just these fracture characteristics mentioned above that ensure the fine control of the cracking plane. 相似文献
6.
Wen Ganghua Tang Ping Yan Guangting 《保鲜与加工》1991,(6):32-37
A calculation formula of stirring energy in liquid steel is set up for bottom-blown O2 and CH,| in the combined blown converter, and the main factors which have an effect on stirring energy and the variation law of stirring energy in steel-making process are discussed. 相似文献
7.
Wang Caihua Wang Chengliang 《保鲜与加工》1990,(6):9-18
In this paper the section sizes of box expansion arm of crane truck are optimized in order that the weight of the arm will be the lightest on conditions that strength, rigidity, stability and size constraints are satisfactory. The fuzzy factors which influence design and the fuzziness of constraint conditions are considered. The unsymmetry mode of fuzzy optimization is established and solved by the method of optimal level cut set. Examples show that the effect is notable. 相似文献
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In this paper the test results of mixed mode fracture of three kinds of brittle rock under two kinds of stress paths are reported. The fracture mechanism and failure patterns of brittle lock under different stress paths are discussed. Theory analysis and test results show that the Compression- Shear fracture criterion of brittle rock can be expressed: 相似文献
10.
Wu Zhiqiang Zeng Xiangren 《保鲜与加工》1992,(4):73-79
This paper analyses the additional stray losses of transformer winding caused by harmonics,and suggests that the influence of harmonics should be taken into consideration in the selection of the conductor' s size in rectifier transformer and converter transformer design. 相似文献
11.
Zheng Zijiu Huang Weigang 《保鲜与加工》1991,(2):90-95
The effects of restraint stress on phase transformation and fracture toughness COD in weld HAZ of 15MnMoVNRE steel were studied by means of weld thermal simulation and COD testing. The results show that restraint stress accelerates phase transformation and makes the fracture toughness COD higher. 相似文献
12.
Xiao Mingxin 《保鲜与加工》1988,(2)
This paper presents two energy functionals which are made as stationary values. Thus, the theorem of stationary value of weighted generalized potential energy and the theorem of stationary value of weighted generalized complementary energy are established. In the first theorem, the stress boundary weighting function must be equal to the internal weighting function while the displacement boundary weighting function is independen; and in the (?)econd theorem, the displacement boundary weighting function must be equal to the internal weighting function while the stress boundary weighting function is independent. 相似文献
13.
The influenfial factors of stratification plane to smooth blasting are studied according to the ti eory of smooth blasting and the anslysis of static stress. The results show that the angle p between the maximum principal plane and the rertical line of stratification plane has some influence on the fracture of rock masses. 相似文献
14.
Zhang Zongyi Xu Guoyu Yang Xiutai 《保鲜与加工》1992,(4):106-110
Two methods for load expression in production simulation are studied,and the
errors are analyzed and compared when the two methods are used in the direct method of probabilistic production simulation. 相似文献
15.
In this paper, on the basis of the compressive tests of composte rock, the different kinds of mechanical properties of composite rock under different bond states are discussed. Authers found that all mechanical properties of composite rock relate to the bond strength between layers and are dilferent when the layers'' bond strength is changed. With increasing the bond strength between layers of the composite rock, the limiting strength, elastic modulus, and breaking energy increase, and this phenomenon is to be stability gradually when they reach some volue, with increasing the layers'' bond strength, the poson ratio reduces. 相似文献
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17.
THE STRAIN OF THE BARS IN THE STRUCTURAL COLUMNS OF THE PRESTRESSED EARTHQUAKE-RESISTANT BRICK-WALLS
Luo Wankang 《保鲜与加工》1995,(1)
Through the comparative tests of prestressed and non-prestressed brick-walls un-der the repeated lateral loading,the effect of the prestress-force to the strain distribution in the non-prestressed bars of the structural columns has been investigated.This effect is beneficial:the pre-stress-force will reduce the value of strain in the bars of the lower part in the columns and uniformize the strain distribution along the whole height of the columns.Furthermore,instead of a strainreduction,the strain of prestressed be will increase along with the increasing of the lateral load.Thus,the coefficient of prestress-force-increase could be calculated in the tWo stages of the crack-resistance and ultimate bearing capacity.As a result,both the prestressed and non-prestressed barsare able to give the potential of their bearing capacity a full play,and improve the earthquake-resis-tant property. 相似文献
18.
Zhang Peiyuan 《保鲜与加工》1988,(2)
Using the flaw-detecting with ultrasonic wave one may know the equivalant area of a crack that burys in the member. If the crack is ellipse shaped, the equivalant area is constant, and the distribution function of its major semiaxle and the plane strain fracture toughness of the material are given, then we would get the probability of reliability of the member under the uniform tension. In this condition, a formula of calculating the probability would be provided in this paper. Because a simple and enough precise approximate function has been introduced the formula in the paper is simple in shape and easy to use. 相似文献
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20.
Zhang Hongji Li Longjian 《保鲜与加工》1992,(2):32-39
The effect of the convective heat transfer in the entrance region of the tube on the temperature field and the maximum temperature of the tube material in the tube -mouth region of the high temperature heat exchange equipment is examined by numerical analysis. The computations on the basis of four different formulas for convection heat transfer coefficient are performed. The computed results indicate that the efect can not be ignored as for heat protection of the tube -mouth region and it is resapnable and secure that the mean convective heat transfer coefficient with taking account of the effect of the entrance region is used in the thermal design of the tube -mouth region. 相似文献