Papers by Keyword: Static Strength

Abstract: The results of experimental studies of the impact strength of samples of concrete and steel fiber concrete are presented. For dispersed reinforcement, three types of steel fiber were used - with bent ends, wave and flattened. Tests were conducted to determine the static and dynamic bending strength, and then - impact tests on the pendulum headstock MK-30. It was found that the impact strength increases significantly in the presence of fiber, but the type of fiber has almost no effect on it. Since specimens reinforced with a fiber content of 1.0 and 1.5% differ slightly in impact strength, 1.0% dispersed reinforcement in volume is recommended, both under static and dynamic loads.

Abstract: The features of the formation of the structure and physical and mechanical properties of all-in-one compounds of low-alloy steels are studied. It is shown that the quality and strength properties of permanent joints depend on the energy parameters of the technological process of their manufacture. The technological process is accompanied by melting, transfer and crystallization of the weld metal from the melt, which has a dominant effect on the structure, indicators of static and dynamic strength of welded joints. The ranges of welding modes that have the greatest impact on the structural and mechanical properties of the zone of permanent joints in the temperature range from +20 degrees to minus 60 degrees Celsius. The results of the research can be widely used in the practice of repair and installation works of structures of the Northern design, working in conditions of naturally low climatic temperatures.

Abstract: In the welding process, the welding strain and deformation of the city rail aluminum alloy flankwall are inevitable as a result of local heating, and carrying capacity of the structure will be affected by the welding stress and deformation. In the mean time, it puts forward some requirements for the clamp process, the clamping force can reduce the deformation of the workpiece. But a great change of force will produce in the clamp position during the process of welding, this force changes are easy to cause brittle fracture and fatigue damage of the clamp. In this paper, it gives simulation analysis to workpiece by using ANSYS analysis software and Gauss heat source model. Finally, the conclusion is sum up compared with the actual data.

Abstract: An experimental approach developed and used for an evaluation of basic static mechanical properties of textile fabric with predominantly longitudinal orientation of yarns, namely static strength and elastic modulus, is described in the paper. The fabric was made using yarns of a dark colour, but no further details were available. Attempts to test just the fabric were not successful and valid due to problems with gripping. Therefore, thin composite plates made of the fabric as the main constituent were sectioned and longitudinal strips were statically loaded with strain measurement. To evaluate the elastic modulus and strength of the fabric in itself, the following steps were performed: (i) cross section area of the strips was evaluated using optical microscope considering effects of the corrugated specimen surface, (ii) area of resin and pores between the yarns was eliminated using Quick PHOTO Industrial 2.3 software and eventually (iii) total cross section of fibres within the yarns was estimated on the basis of closest arrangement assumption. The results are presented and discussed from the viewpoint of a possible aramid type.

Abstract: The current research deals with special hybrid metal-composite joints (MCJ) which use thin sheet-metal reinforcement with small die-fixed pins (2-3 mm) embedded into the composite part of the joint. This technological trick significantly and positively influences strength of the metal-composite bolted joints loaded in out-of-plane direction. This fact was proved by comparison of pull-off static and fatigue tests results of MCJs with and without reinforcement.

Abstract: In order to investigate the influence of local thermal treatment to microstructure and static mechanical behavior on clinched joints of cold rolling steel (SPCC) . The clinched joint performed local thermal treatment based on the test platform, and successively adopting metallographic, micro-hardness and static mechanics behavior test. The result show that the microstructure of SPCC clinching joints found a large amount of lath martensite after quenching treatment, and in comparison to which without local thermal treatment, its static strength is enhanced by 45.39% and its hardness increased by 77.78% .

Abstract: In the paper the assessment was made of the influence of adhesive layer on strength properties of multilayer pipes. The conducted tests revealed that during the multilayer pipe’s construction process it is necessary to take into account the adhesive’s immediate strength, fatigue life and the change in their values depending on the temperature and the loading working on the pipe in the exploitation conditions. The adhesive’s influence or the lack thereof on the fatigue life depends on the level of stress σ_max. This influence is minimal in the area of the greatest working stress and increases along with the decrease of stress.

Abstract: The safety of a reinforced concrete frame building with cracks on a large area of its wall was investigated by using numerical analysis and field tests. The cracks were caused by the roof additional equipments. The layout of the roof additional equipments was measured to determine their additional loads. The width and depth of existing cracks was also measured. The static strength analysis based on the finite element technique is used to evaluate the influence of the additional loads on structural strength. The research results show the unreasonable supports of additional loads and the insufficient stiffness of secondary beams are the main reasons for causing cracks on the wall, and a reinforcement and repair thought for the building is proposed.

Abstract: This paper estimates the static strength of a certain type of cooling fan designed by a company in the rotating speed of 1260 rpm and 1380 rpm, evaluates static strength according to the cooling fan’s permissible stress in F state and T1 state, estimates the fatigue strength according to the operation load of cooling fan suffering from different direction when locomotive running and evaluates the cooling fan fatigue life according to the IIW standard. Static strength and fatigue strength calculation using ANSYS companies in the United States commercial version of the ANSYS software to complete.

Abstract: Aeolian sand is one commonly used subgrade filling in Xinjiang Oasis-desert region, engineering practices also proved its applicability as subgrade filling. In order to find the law of Aeolian sand subgrade static strength after cyclic loading, the paper studied the static strength of Aeolian sand before and after cyclic loading through the dynamic and static triaxial tests. It is concluded that the greater cyclic loading is, the more Aeolian sand static strength peak decreases. When cyclic loading is small, the bigger confining pressure and consolidation ratio are, the static strength peak increases more after cyclic loading. The bigger initial static deviator stress is, the more Aeolian sand static strength peak reduces. The frequency of cyclic loading has little effect on static strength. In order to keep the stability of low embankment, we should restrict overload , ensure subgrade and foundation consolidation adequately, at the same time using gravel or geosynthetic materials to package edge of roadbed, so as to increase confining pressure. The research results can provide reference for the design and construction of Aeolian sand low subgrade in Xinjiang Oasis-desert region.