Applied Mechanics and Materials Vols. 744-746

Abstract: The micromechanical fracture models were used to study the fracture behavior of the welded connection and welded-bolted connection joints. The Void Growth Model was implemented in commercial finite element software ABAQUS through the user-defined subroutines. The results predicted that cracks initiated at the edge of the welds and extended along the length and thickness of the welds. Comparing the effects of equivalent plastic strain and stress triaxiality for the fracture of the first failure element of both beam-to-column joints, we found that the equivalent plastic strain grew linearly as the loads increased and the weld of the lower flange generated cracks when the stress triaxiality increased at maximum value.

Abstract: The existed concrete column reinforced by external steel tube is a common reinforcement technique and widely used in engineering. However, the computational theory on bearing capacity of the reinforced structure is insufficient at present. In the condition that the existed column concrete before completely unloading is reinforced or the initial stress level is low, the mechanics characteristics of reinforced components were analyzed based on the limit equilibrium method, and then the computational equations of the bearing capacity subjected to axial loading after the short column pier reinforced structure had been deduced. Comparing the calculation results with the correspondent experimental data shows that the deduced equation can provide reasonable results for predicting the axial bearing capacity, which provides a support for the computation of the bearing capacity for the reinforcement pier in practice.

Abstract: This paper analyzes the reason of a steel truss building which collapsed under a snow disaster. Firstly, the investigation and inspection in site are introduced. Secondly, based on the on site work, such as the property of the metal materials and the quality of the welding joint, the status of the structure is comprehensively determined. Thirdly, through calculation with the former results, the reason of the collapse accident is obtained. Finally, some related suggestions are proposed for the design and construction of this kind of structure.

Abstract: On the basis of a comparative study, this paper aims to determine the maximum loads that can occur in operating conditions on the cardanic transmission assembly of motor vehicles in the open or closed loop configurations. The research is conducted under static conditions using finite elements and shows the components with their maximum values obtained in normal operating conditions.

Abstract: Cable-braced grid shell is a hybrid structure combined rigid steel tube and flexible cable. The paper presents the variation law of stability and deformation performance of cable-braced grid shell with different section forms of steel tube, as section of cable, prestress of cable and span-to-height ratio vary. Economic and reasonable section form of steel tube is proposed as a reference for the practical engineering design.

Abstract: Harbor projects have to face harsh marine environment, and the corrosion damage of steel structures is rather serious. It is an insurance for structural safety and an important measure of durable that strengthening of corrosion control, selecting the appropriate anti-corrosion technology, reasonable design, scientific construction and appropriate maintenance management, and it has an important economic and strategic significance.

Abstract: Based on the characteristics of space truss structures, the concept of modal strain energy is introduced and square difference in elemental modal strain is presented. Through the square difference in elemental modal strain and wavelet transform, this paper presents a method for space truss structure damage recognition. The structural damage index is presented with the change of wavelet coefficients. Numerical simulation results show that: this method is effective to locate the single, multiple damages and light, severe damage with the first mode information. The preliminary tries for damage extent identification were made by the wavelet coefficients.

Abstract: The durability of coastal reinforced concrete bridge structures will be deteriorated during service due to fatigue loads and Chloride erosion. Through the microscopic tests of reinforced concrete beams after fatigue and seawater corrosion, 10 reinforced concrete beams divided into 5 groups subjected to different fatigue loads were investigated under the alternative action of seawater corrosion, where the deterioration of concrete was degraded. From the experiment, it can be concluded that there was significant self-healing phenomenon on the cracked beams by fatigue loading; And there was regular and clear microcracks in the beams when the maximum fatigue load between 0.16~0.24Pu; the cracks of the beams became obvious,micro cracks increased and crystals can be significantly seen in cracks and low lying location when the maximum fatigue load exceeds 0.24Pu.

Abstract: Applied to the structural damage identification, Modal Flexibility is better than the Modal Frequency and Modal Displacement, the indicators of Flexibility Curvature are effective and sensitive. This paper proposes a new detection indicator which is Flexibility Curvature Difference Rate (FCDR) that by using the change rate of diagonal elements of flexibility curvature difference when before and after damage. The numerical examples of a simple beam, a continuous beam and a frame with the damage conditions of the different positions and different degrees are used to verify FCDR. The result shows that FCDR can well identify the numerical examples damages, and sensitively diagnose the damage near the supports of beam and the nodes of framework.