Applied Mechanics and Materials Vols. 670-671

Abstract: In the civil engineering structures, when concrete structure withstand external loads, internal defects such as micro-cracks gradually developed, eventually will lead to the destruction of the concrete. Currently, there are two types of strength failure criterion of concrete, strength failure criterion based on stress-space and strength failure criterion based on strain-space, both of which have advantages and disadvantages, this paper introduces the research status of the two strength failure criteria of concrete, and the problems need further study in the future. It plays a strong practical significance in scientific research.

Abstract: Compared with tradition asphalt mixture, the construction temperature of high viscosity asphalt mixture is higher in the tunnel construction. It is necessary to adopt the warm mix technique of adding warm mix additives in high viscosity asphalt. The paper analysis the temperature decrease effect in adding zeolite powder in high viscosity asphalt and the performance of asphalt mixture with zeolite powder additive. The study result shows that the adding 8% of zeolite powder in viscous asphalt can cut viscous asphalt construction temperature of 15 °C or so. Air voids as one kind of volume indicators determines the high viscosity asphalt construction temperature, the cooling amplitude rate is 10 ~ 15 °C.

Abstract: Porous concrete planted with grass is attractive both environmentally and esthetically for applications in residential driveway, sidewalk and parking lots. Disposal of papermaking sludge is a challenging environmental problem. As a possible solution, grass cultivation in porous concrete filled with mixtures of papermaking sludge and soil was studied. Bermuda grass, Perennial ryegrass, and Tall Fescue were tested. Experimental results showed that the papermaking sludge retarded the germination of grass seeds only slightly, while promoted the growth of grass stems and the development of grass roots significantly. The optimum ratio of the papermaking sludge to soil appears to be in the range of 25 to 50%. Therefore, it is believed that papermaking sludge is suitable for grasses cultivation in the porous concrete.

Abstract: Any processing of bulk materials requires their moving and uniform feed (dosage). On this depends the quality and efficiency of many technological processes. For uniform and controlled supply of bulk, materials for transporting or processing machines use feeders. Among feeders in recent years, an increasing distribution received disk vibrating feeders, which are characterized by small size, without moving parts, prostate, reliability, accuracy and smooth control supply. Disk vibrating feeder has a horizontal spreading disk, which is located coaxially and with a gap below the outlet of the hopper. Spreading disk is connected with vibratory drive. This research was aimed at finding technical solutions ensuring the reduction of specific energy consumption of disk vibrating feeder. The study showed, that if the spreading disc perform with a central hole, which is closed by an elastic membrane, then this can significantly reduce the specific energy consumption per unit of production.

Abstract: The opportunity of production of effective non-cement binders with using of different morphological and structural types of aluminosilicates and silicates is studied on the basis of data of phase and structural features of natural raw materials – perlite and quartz sand.

Abstract: The article in question presents the comparison of thermo-protective characteristics of building envelopes constructed on the basis of cold formed steel members according to the results of computer modeling, engineering methods and full-scale experiment. Two comparative parameters were chosen: the coefficient of uniformity and the difference in temperatures of the construction internal surface. The influence of various “input” parameters (thickness, insulation thermo conduction and etc.) on thermo-protective characteristics has been analyzed. The asymptotical character of connection between thermo resistance of non-uniform building envelope and insulation thermo conduction has been deduced.

Abstract: The research achievement of strata movement law caused by subway construction and control standards was summarized and analyzed, and point out that this research on the laws of strata movement (or deformation) caused by subway construction mainly focused on three aspects. The first was research on the ground vertical settlement laws perpendicular to the tunnel excavation direction. The second was research on the ground vertical settlement laws parallel to the tunnel excavation direction. The third was research on the ground horizontal movement regularity perpendicular to the tunnel excavation direction. Through the analysis of the current research results, it is points out the shortages existing in the research, and deeply research in the future. It may provide the theoretical basis, also for practical engineering application provides a certain technical support.

Abstract: A multi-functional resistance furnace has been invented. Its main components include a normal resistance furnace and an electronic balance outside the furnace. The weight of the sample being heated inside the furnace was transmitted through a set of attachments and measured by the balance. Both the real-time furnace temperatures and the sample weights were recorded by a computer. Thermogravimetric curves then can be obtained. The present setup is advantageous over the traditional commercial thermogravimetric analyzers in analyzing samples with a large mass. The multi-functional furnace is cheap and may find important industrial applications such as raw materials thermal analysis or products oxidation or anti-oxidation tests.

Abstract: Three-dimensional elastic-plastic finite element simulation method is adopted to analyze the distribution of the equivalent stress, velocity field, surface area, tooth height and transverse knurling experiment is performed to testify the simulated results. The comparison between tooth profile of simulation and experimental one was carried out to confirm the forming rule of triangular tooth on the surface of tube. This study is a prerequisite for related subsequent research about knurling process.

Abstract: This paper presents a method of estimating cutting forces of the tool by taking the tool’s run out into account during micro milling processes. The thickness of uncut chip is modelled based on the trochoidal trajectory synthesized from the rotational motion, the feed motion, and the run out of rotational micro tools. The strain gradient plasticity theory is then used in conjunction with the Johnson–Cook constitutive equation to calculate flow stresses, where the influence of the plough shear on the rake face and the elastic recovery on the flank face is considered. The calculated cutting forces using the proposed method for micro milling processes show a satisfactory agreement with existing experimental results.