Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Archives of Civil and Mechanical Engineering

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Shear failure and mechanical behaviors of granite with discontinuous joints under dynamic disturbance: laboratory tests and numerical simulation

Gong Hangli, Wang Gang, Luo Yi, Liu Tingting, Li Xinping, Liu Xiqi

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 3

art. no. e171, 2023

To investigate the fracture mechanical behavior and failure mechanism of jointed rock mass under compression and shear load. Conventional shear tests and shear tests under normal disturbances were conducted using an electro-hydraulic servo-motor loading system. Meanwhile, the discrete-element program particle flow code was adopted to establish a numerical shear model, and to discuss the microscopic deterioration characteristics and energy dissipation mechanism during shear fracture of rocks with discontinuous joints under joint action of normal static loads and dynamic disturbance. Compared with the conventional shear tests, shear test results under normal disturbances show the following specificities in terms of their macroscopic and microscopic mechanical properties as well as energy evolution: (1) frequent dynamic disturbances accelerate the non-steady fracture process of jointed rock samples and promote occurrence of the weakening effect of shear fracture. (2) The step-like abrupt increase in micro-cracks becomes more obvious before reaching the peak shear stress. (3) The energy-storage capacity and failure resistance of the rocks are weakened. The research results are of great significance for further understanding the dynamic catastrophe effect of deep rock mass.

Microstructure and mechanical properties of TiC/Ti matrix composites and Ti–48Al–2Cr–2Nb alloy joints brazed with Ti–28Ni eutectic filler alloy

Dong Duo, Xu Haitao, Zhu Dongdong, Wang Gang, He Qing, Lin Junpin

Archives of Civil and Mechanical Engineering

2019

Vol. 19, no. 4

1259--1267

Ti–48Al–2Cr–2Nb and TiC/Ti matrix composites were successfully joined using Ti–28Ni eutectic filler metal at different brazing temperatures. Microstructure and mechanical properties of the joints were systematically studied. The results showed that the joints all showed integral interfaces and the microstructures of the joints for 980 8C/15 min were detected as Ti-48Al-2Cr-2Nb/a2-Ti3Al + t3-Al3NiTi2/a2-Ti3Al/Ti(s,s) + d-Ti2Ni + TiC/Ti matrix composites. As brazing temperature increased, continuous Ti2Ni layer diminish and Ti2Ni phase became more discrete. However, a2-Ti3Al rich layer has thickened which deteriorates the properties of the joints. The highest shear strength achieved 469.5 MPa as the joint brazed at 1010 8C for 15 min. The evolution of microstructures brazed with different tem-peratures was studied and its relationship with the shear strength was also revealed in details.