Applied Mechanics and Materials Vols. 71-78

Abstract: To study load carrying capacity for Lap Region between the Skirt and Composite Case(LRSC) of the solid rocket motor(SRM),made the stress of layer out of skirt as the research object, established the two-dimensional axisymmetric finite element model for compsite case,analysed the main factor(lap length) for carrying capacity of LRSC,and verified the conclusions by calculation.Optimized the lap length ranged from 40mm to 60mm, proposed model of the optimal lap length and optimization method,calculated optimal lap length under different axial loads.The results show that, with the increase of lap length of skirt, the load bearing capacity of LRSC enhances first and depresses then,exists a great value,which of the corresponding lap length is optimal;With the increase of axial load,optimal lap length monotonously will increase.

Abstract: Experiments were conducted to study the effects of source rock state and stone powder on freeze-thaw resistance of concrete with proto-machine-made sand, the strength grade of concrete was C50, the source rock states were gravel and crushed stone, the contents of stone powder in sand were 5%, 9% and 13% respectively. The values of relative dynamic elastic modulus and mass of concrete at different freeze-thaw cycle times were measured, the reduction of relative dynamic elastic modulus and mass loss were calculated to evaluate the freeze-thaw resistance of concrete. The results show that freeze-thaw resistances are controlled by the reduction of relative dynamic elastic modulus of concrete, which are good of concrete with proto-machine-made sand of gravel and crushed stone, and increases with the increasing content of stone powder in sand made of gravel. The reasons leading to difference of freeze-thaw resistance of concrete with sand made of gravel and crushed stone are discussed.

Abstract: Based on a series tests, the properties of proto-machine-made sand of gravel such as grain feature, fineness modulus, grading, density, void ratio and MB value as well as the fineness distribution of stone powder were studied, the influences of content of stone powder on these properties of sand and strength of cement mortar were investigated. The results are introduced in the paper, some of them contribute to explain the special properties of concrete mixed with proto- machine-made sand.

Abstract: The urban value is the sum total of the entire human labor which is formed by the accumulating investment as well as the construction activities in the urban city. The urban value is one of the most significant elements in the composition of the real estate value. Urban value determines the value of real estate. Similarity, the value of real estate also has effects on urban value. In accordance with the empirical research, it indicates that the general complexity and dynamics of urban value conform to the using space of Grey Correlative Analysis. To make the analysis of urban value based on Grey Correlative Analysis can explain the differences of the real development trend between each city. According to Grey Correlative Analysis, the main factors that affect urban value are urban economy value, urban position value and urban resources value in turn. Effects on urban value of urban infrastructure and urban scope value are weak. Research for urban value based on the Grey Correlative Analysis provides the more rational and logical decision-making platform to the most acceptable subsystem in the urban economic activities objectively--the activities for the investment and construction of the urban real estate.

Abstract: The energy generation efficiency of Building Intergraded Photovoltaic Systems (BIPV) system relies much on the panel’s surface solar radiation received. In the projection of annual power generation of photovoltaic panels, local global solar radiation plays a pivotal role for reliable estimation process. The purpose of this paper is to develop an hourly typical solar radiation year (TSRY) as fundamental meteorological database for utilizing the estimation process. The TSRY should be interpretable to local long-term climate variations, thus, ten years' hourly meteorological data were gathered to formulate a typical year by means of modified Sandia method herein. A total of four cities' hourly typical years from northern to southern Taiwan were established in this paper. Orientation and inclination effect of the PV panel were also discussed in terms of daily averaged global solar radiation that cumulate from TSRY.

Abstract: In order to solve the problem of picking carya cathayensis, the paper studies picking methods of the fruit and picking characteristics of carya cathayensis, The vibration method was put forward for carya cathayensis picking. Test results show that picking carya cathayensis with a vibration method is feasible. The main technical parameters of vibration picking for carya cathayensis was proposed，the paper provides a theoretical basis for the mechanized of picking carya cathayensis.

Abstract: To improve the picking efficiency and processing quality of carya cathayensis, this paper analyzes the present problems in harvesting and processing of the carya cathayensis. The vibration picking method for carya cathayensis was put forward.Aim at process of classification and broking shell of carya cathayensis , the short of technology and key technical problems was pointed out. Finally, future research direction of picking and processing technology for carya cathayensis was put forward.

Abstract: Based on some special merits such as self-stability, energy-consuming-efficiency, less pollution, high reliability, and so on, high temperature superconducting maglev (HTSM) is one of the promising potential technologies among present Maglev technologies for the future evacuated tube transportation (ETT). In this paper, the possibility, the merits, and the demerits of the applications of HTSM in ETT system are investigated. Especially, two application issues, liquid nitrogen vessel on the vehicle and isolated gate set in ETT, are discussed and solutions are suggested. On the first issue, this paper suggests to install a pressure relief valve on the sealed liquid nitrogen vessel so as to reduce the liquid nitrogen vaporization in the vacuum tube. As for the second issue, this paper recommends to use HTSM permanent magnet (PM) track structure with a streamline separated gap between the surface of track and the bottom of liquid nitrogen vessel. Those guideway structure could fit to the isolation gate setting in ETT.

Abstract: Double L-stiffened plate or haunch is used to strengthen the connection to meet the requirement of the code for seismic design of buildings: The principle of strong connection-weak connected member. The two kinds of reinforced connections are simple and easy to construct. Using software ANSYS to research is done on the connection under the monotonic load and low-frequency cyclic load. The results show that: the reinforced connections have high bearing capacity, superior hysteretic performance, and very good ductility; when failure the deformation of the joint region becomes smaller, and the plastic hinge shifts away from the region so as to prevent the brittle failure of the region; the beam has a long yielding plateau, and the bearing capacity decreases not very much after the beam yielding.

Abstract: The thesis presents an research on the time-varying behavior of cement grouts with different water-cement ratio of 0.5,0.55,0.6,0.65,0.7,0.75,0.8,0.9,1.0,1.1,1.25,1.0,2.0,5.0 and10.0 at 0 minute, 5minutes,10minutes,20minutes,30minutes,60minutes,respectively.This was to investigate the time-varying behavior of reheological parameters of cement grouts with different water-cement ratios.It confirmed that: consistency coefficient and viscosity are time-varying reheological parameters, while rheological index and initial stress(yield stress) are time-independent behavior;the flow pattern properties of cement grouts with different water-cement ratios could remain unchanged with time; the laws with time change of consistency coefficient and viscosity of cement grouts accord exponential function, c_p(t)=c₀×e^kt (Power-law fluid) or h_p(t)=h₀×e^kt(Newtonian fluid or Bingham fluid).These research results have very important realistic value and theory meaning.