Papers by Author: Xia Cao

Abstract: The effect of thixo-forging process on morphologies of particles that affect fracture mode of 7A04 alloy was studied. Microstructure and fracture surfaces of thixo-forged samples were investigated by image analyzing technique and scanning electron microscopy. The analyses of the ruptured surface were conducted with specimens taken in-situ from ruptured surfaces of thixo-forged parts. It is suggested that samples fractured in an area with higher liquid fraction have superior mechanical properties, especially elongation, and consequently a failure type of inter-crystalline cracking could be the main fracture mechanism. On the contrary, samples fractured in an area with lower liquid fraction have inferior mechanical properties and the principal resistance force is created by the contacting solid particles, a failure type of trans-crystalline rupture could be the main fracture mechanism.

Abstract: Owing to the outstanding advantages of unbonded prestressed technology, it has been widely used in high-rise building floor. However, with the continuous improvement of the function requirements of the building, the boards with openings become more and more common, not only in new constructions but also in renovation projects. These holes will change the mechanical properties of the original floor, and cause stress concentration around the holes easily. This article carries on the simulation analysis by modeling the experimental model using ANSYS software, focuses on the deflection, crack and ultimate load of unbonded post-tensioned prestressed concrete board with open-hole (under uniform load in tensioning and loading stage). After making the comparative analyses to the mechanical behavior and failure mechanism under the different locations of the holes, the simulation results are compared with experimental results, shows that ANSYS can simulate the whole process of loading better, provides theoretical basis for its application and promotion in practical engineering.