Applied Mechanics and Materials Vols. 166-169

Abstract: The stress concentration around a hole in an infinite plate is discussed in elasticity. However, the problem that how large of a plate can be considered as an infinite plate does not be solved still in engineering. Based on the analysis of prerequisite of Kirch’s solution in the rectangular coordinates, two indicators defined as dimensionless stresses are proposed to determine the application range of Kirch’s stress solution. In relation to the diameter of the central hole, several minimum coefficients of the dimension of the plate are obtained and discussed. These coefficients are useful to engineers.

Abstract: The performance of concrete materials under high temperature is more complex than that under room temperature. This paper, by analyzing the mechanical property of concrete materials under high temperature(fire), probes into the changing law of the concrete materials' compressive strength under different temperatures (16 °C-800 °C) and different static placing time and makes a comparison on the concrete materials' strength between natural cooling and water cooling; illustrates the relationships of concrete materials' compressive strength and temperature, holding time and cooling and other factors under high temperature(fire).

Abstract: In this paper, by using Hadamard inequality and Cauchy inequality, an extension of Hilbert inequality is established.

Abstract: In this paper, by using Maximum-minimum monotonic theorem and estimating the weight coefficient, a refinement of Hardy- Hilbert inequality is established.

Abstract: The retaining walls were divided into water retaining wall and soil retaining wall, they were built to cut off rivers or prevent soil structures from sliding. In engineering the stress state of the structure played an important role to analysis the working condition and to guarantee the project safety. The stress state of any point in the water retaining wall and soil retaining wall were studied based on the elasticity theory and soil mechanics. The method of semi-inverse was used to deduce the stress intensity of the retaining wall in polar coordinate. And if the failure criteria and strength conditions of the retaining wall were known, the working and safety state of the structure could be checked from the stress intensity.

Abstract: During the process of structure design, non uniform load on beam usually is considered as similar uniform load. Some analytic solution formulas of bending moment about beams acted on symmetric load are deduced. Table of equivalent uniform load coefficient according to the principle of bending moment equivalency is listed. The feasibility and beware are also discussed.

Abstract: An experiment studies the forced performances of concrete bending members in three different times of freeze-thaw cycles and reinforced corrosion through fast freeze-thaw method and electrochemical method, it analyzes the influencing law on the anti-deformed capacity of concrete bending member influenced by the phenomenon of frost-heave and reinforced. On this basis, it builds a stiffness calculation model of concrete bending member in freeze-thaw & Corrosion environment.

Abstract: Duo to non-linearity of ground material’s behavior, the error will be introduced using traditional superposition method to calculate bearing capacity. The main cause of superposition error is that bearing capacity factors based on failure mechanism of weightless soil is not applicable for weight soil. Based on slip line method, variation trend of error introduced by superposition method is investigated. The investigation of this paper showed that, bearing capacity calculated by traditional superposition method is conservative, and the error increased with increasing of internal fractional angle.

Abstract: Pecans are unique in our country. They not only have rich nutritive value, but also have great economic value in fertilizer, feed and activated carbon so on. But because of the complex terrain, it brought much inconvenience for pecan picking. This article tested samples of HengLu town of LinAn city and analysis pecan dynamic characteristics. Then find a kind of pecan dynamic model based on vibration and provide the theory basis for vibration type pecan picking machinery.

Abstract: In order to accurately describe the impact is on the redirection of the secondary fracturing caused by stress field distribution of the reservoir , according to the superposition principle of the potential, builds the pore pressure induced model around refracturing wells ; introduces the fluid influence factor coefficient , builds initial artificial crack induced stress field model. Finally, the three stress applies the linear superposition principle .Obtaining the total stress field before the refracturing , provides a reliable theoretical calculation basis for the induced stress calculation