Applied Mechanics and Materials Vol. 372

Abstract: This paper reports an investigation in which the performance of fly ash, blast furnace slag and silica fume high strength concretes were studied under 7 and 28 curing days. Three high strength concrete mixtures were made in this investigation. Mixtures containing 25% fly ash, 25% fly ash and 25% blast furnace slag, and 5% silica fume as cement replacement, respectively. The water-binder ratio of all the high strength concrete mixtures was kept constant at 0.34. The replacement of silica fume in the high strength concrete mixtures indicated higher value of the compressive strength, splitting tensile and modulus of elasticity. In addition, blast furnace slag is effective for strength and modulus of elasticity improvement between 7 to 28 curing days.

Abstract: This paper addresses the results of an extensive experimental study on the compressive, splitting tensile strength modulus of elasticity in long-term. These tests were carried out to investigate the mechanical properties of HPC for 56 and 91days. In this work, High performance concrete was designed a water-binder ratio of 0.40. In addition, three different concrete mixes were used in these specimens. The results properties of HPC with fly Ash, blast furnace slag and silica fume were effective for compressive strength splitting tensile strength and modulus of elasticity improvement between 56 to 91 curing days.

Abstract: The use of mineral admixture such as fly ash, blast furnace slag and silica fume in making high performance concrete has increased. The objective of this study is to investigate mechanical properties of compressive strength, splitting tensile strength and modulus of elasticity of hardened high performance concrete.

Abstract: This paper introduce the basic overview of the project of Shenyang Metro Lishui City, trough the isolation technology applied in the the project of Shenyang Metro Lishui City, we talk about the basic concepts of the isolated structure,category and the application. It describes the structure and performance comparison of laminated rubber bearings.At last, briefly introduced the problems to be solved of the isolated structure.

Abstract: The reduction of electrical energy consumption in buildings is a subject of great interest in the international scientific community. In buildings with a lot of available natural light, designed with large glazed surfaces, the artificial lighting system is often oversized and cannot be divided into segments to meet lighting demands during daylight hours.This article presents an experimental study, conducted in a university lecture hall that has a glazed surface covering the whole wall at one end, which provides a level of internal illumination that is only sufficient for the area next to the window itself, even when the outside lighting conditions are very bright. It is therefore necessary to turn on the artificial lighting system.The mathematical approach used in this paper has been successfully applied by the authors in other fields of science [1-2].Using an automatic dimmer system, the calibration of which is based on experimental measurements, the lighting is arranged in such a way as to illuminate the most disadvantaged areas of the room, and then to extend itself gradually to the whole of the room, over the period of time that the lecture hall is in use.

Abstract: The purpose of this research is to examine the physical property of the catheter, which made of soft nylon resin and is reinforced with thin stainless wires called braid. The effect of braid on the mechanical property of the catheter is revealed by investigating the relationship of the stress relaxation and the relative angle between the braid and the principal axis of stress under combined loading of bending and torsion. Inthe first place, in order to investigate the phenomenon of stress relaxation under combined loading, the experiments under single stage step strain have been carried out by changing the ratio of bending and torsion, and the relation between the coefficient of viscosity and the relative angle of the braid is revealed. In the second place, the experiment under two-stage step strain are conducted by changing the order of bending and torsion, and the effect of these loading histories on the visco-elastic properties is examined. Moreover, the numerical simulation under two-stage step strain is carried out by using the estimated coefficient of viscosity, and in this paper, the validity of this analytical model is confirmed by comparing with the experimental results.

Abstract: Crack growth under cyclic loading causes failure of machine components. Non-destructive methods that can be related to plastic deformation around crack tip are necessary to study the crack growth. In the present work, a scanning Hall probe microscope (SHPM) equipped with GaAs film sensors was used to observe the magnetic fields around the plastic deformation induced by Vicker's indentations in tool steel specimens (SKS93, JIS B 4404: 2006, equivalent to AISI W4 tool steel). The magnetic field around a 2.94N-indentation was compared to that of a 294N-indentation. It was found that the decrease in the magnetic fields depends on the plastic deformation size.

Abstract: JIS SUJ2 (high carbon high strength bearing steel) heat treated by repeated quenching was investigated. The microstructure of the bearing traces was observed after heat treatment by laser confocal microscope. In this paper, by mathematical methods, we try to evaluate quantitatively this change of the structure. Homology is a branch of mathematics that allows quantitative describing characteristics of a figure by replacing the figure with algebra. Applying homology we can express the degree of the connection of the figure. Here we use homology to quantify the change of structures by repeated quenching. Keyword: Homology, Rolling contact fatigue, SUJ2, repeated quenching

Abstract: Martensitic high-carbon high-strength SAE 52100 bearing steel is one of the main alloys used for rolling contact applications where high wear resistance is required. Refining the prior austenite grain size through repeated heating is a process commonly used to enhance the materials strength. In this work, the microstructure of repeatedly quenched Ti, N-rich ultra-clean SAE 52100 steel was investigated. The material was melted by an electric furnace and formed by continuous casting and forging, and the crack origin on the fracture surface was investigated. It was found repeated furnace quenching effectively refined the martenstic structure. In order to further understand the structure refinement we need to develop a new quantitative evaluation method. In this paper, the homology method is applied. We can estimate the situation of refinement quantitatively.

Abstract: There were lots of distributed sources in the process of fatigue crack propagation of the lattice boom. Static evaluation of the reliability indicators couldnt be satisfied to solve practical engineering problems. The load and fatigue resistance were regarded as random processes and the fatigue failure of the randomness in a variety of factors, the concept of dynamic reliability of the weights index was proposed, models of dynamic reliability of the weights index were built based on the fatigue bearing capacity mode and limit damage degree mode. Fatigue stress experiments comparisons were done on a crawler crane according to the actual operating conditions with a K-type welded joints prototype. The results show that the dynamic reliability evaluation assessment model is more accurately in the fatigue life evaluation and the method can provide a new assessment method for engineering applications.