Papers by Keyword: Crack Analysis

Abstract: In this work, the utilization of a phase-field ductile fracture model in the failure analysis of advanced steels is investigated. The importance of advanced steels is potentially proven, for instance in automotive industry, due to its light weight, which entails the crucial role of fracture analysis in these structures. A third generation advanced high strength USS CR980XG3™️ AHSS material is considered to perform fracture analyses. For this purpose, the necessary data regarding the stress distribution and fracture patterns from digital image correlation tests are utilized for subsequent numerical experimentations.A recent phase-field model of ductile fracture is employed herein for the analysis of crack advance in this class of materials. The significance of the choice of material properties using this model is shown through the analysis of an experimental fracture benchmark called Shear Fracture specimen, through assessment of crack evolution and force diagrams.

Abstract: According to the experimental data of steel beam for Honglu steel company continuous combination,a newer finite element model is presented.The model takes into account the effect by linear material,slip between concrete and steel beam and prestress as well.Five samples of steel-concrete composite beam are calculated with the model.and the stress, strain, crack propagation of nonlinear numerical simulation analysis is carried out , then the continuous composite cross in the load deflection curve of beams is obtained. As the calculation and analysis show that, the results of numerical analysis and experimental data are consistent with the analysis model. And the model is reasonable and effective.This study provides the basis for the application of continuous steel-concrete composite beams.

Abstract: Based on results of a deformation monitoring exercise, a numerical analysis was done to identify the causes of defects and assess the stability of a reinforced concrete bunker. Different scenarios were tested, among them the effects of coal lateral pressure on the wall, loading of different quadrants of the bunker, temperature differences and effect of differential settlement on crack formation. In calculating the coal pressure, classical theory presented by Rankine was used together with provisions of the design codes. Temperature differences are seen to have a significant effect on the stress distribution whereas differential settlement presents a major concern to the stability of the Bunker.

Abstract: In order to study the bridge of a rail transit line in Guangzhou city, we use the finite element program Midas/FEA. Combining with the structure characteristics of the bridge, we establish space finite element model of piers. The linear and nonlinear analysis have been done respectively. In view of the nonlinear analysis, we analyze the left and right bearing under the most unfavorable load and dead load. The results show that as the ordinary reinforced concrete structure, bridge piers are bending crack under the design load. The width of crack controlled by force is less than the design value, so the bridge piers are in a safe state and it does not affect the normal operation. We noticed that the crack in piers appear a feature that width of crack become narrow in points under force controlling, but in other areas the crack in piers appear a feature that width of crack become wide. We have a preliminary judgment that the cause of this phenomenon may be the construction quality such as the actual reinforced protective layer are excessivecooling measures in the process of the construction of the pier head of mass concrete did not reach the designated positionmaintenance measures were in place and so on. The construction quality cause combined effects of mass concrete shrinkage crack and the structure of normal stress fracture.

Abstract: As a new composite wall system, because of advanced structure, excellent polystyrene insulation board, insulation effect, light weight, the simple and flexible construction method and well adaptability, polystyrene insulation board thin coating of exterior wall thermal insulation technology is widely used in China. In practical applications, thermal bridges and the board surface cracks that caused by improper handling of deformation joints and detailed structure are the main problem of the technology. In this paper, many problems are analyzed such as the crack causes, the plates overlap and the node structure treatment, and also corresponding solutions are proposed.

Abstract: The paper is special for wooden structure housing in villages and towns, and taken appropriate reinforced measures to achieve the standard of seismic design of no collapse in big or medium earthquakes. The 1/2 scale model that loaded horizontally on the shaking table was designed to observe its damage characteristics and make an analysis of its destruction. And the effectiveness of the reinforced method will be assessed.

Abstract: The 5at.% Yb3+-doped YAG crystal was grown by the Czochraski method, and the crystal growth process was investigated. the optimal process parameters were determined as follows: The crystal growing rate for Shoulder growth and equal-diameter growth were 0.8mm/h and 1mm/h, respectively. The optimal Rotation speed of this crystal was 15rad/min, and the axial temperature gradient was 0.01−0.05°C/mm. The impact factors to crystal growth were analyzed theoretically, such as growth rate, rotation speed, thermal effect and crystal size.

Abstract: In this paper is presented a study of the analysis of the stress state of micro specimens exposed to a load inside the column of a High Voltage Electron Microscope (HVTEM), in particular for a Mo single crystal. The experimental tangential stresses distribution images were obtained and compared with theoretical calculations using Naiber approach, obtaining an excellent match.

Abstract: This paper presents an elastostatic crack analysis in three-dimensional (3D), isotropic, functionally graded and linear elastic solids. A boundary element method (BEM) based on boundary-domain integral equations is applied. A multi-domain technique and discontinuous elements at the crack-front are adopted. To show the effects of the materials gradients on the crackopening- displacements (CODs) and the stress intensity factors (SIFs), numerical results for a pennyshaped crack are presented and discussed.