D.Q. Li
,
D. Li
,
L.H. Nan and X.T. Tian National Key Laboratory of Advanced Welding Production Technology
,
HIT
,
Harbin 150001
,
China
金属学报(英文版)
In order to effectively control the stress and distortion which produced in welding process, the dynamic change laws of displacement field is the most important factor. The characteristics of the welding dynamic displacement field is high temperature, high strain velocity, thus ordinary methods such as resistance strain gauge or Moiré method can not be used for the measurement of the zone of high temperature. Speckle interference method has the merits of non-contact, resistance to the disturbance of impure lights, high accuracy of measurement (half of wavelength).The paper represents the measurement of dynamic displacement field of argon-arcspot welding, by which it shows that the method of speckle interference is feasible for the measurement of welding dynamic displacement.
关键词:
welding dynamic displacement field
,
null
,
null
D. Li
材料科学技术（英文）
The internal stress induced by a porous layer or passive layer can assist the applied stress to promote dislocation emission and crack propagation, e:g: when the pipeline steel is buried in the soil containing water, resulting in stress corrosion cracking (SCC). Molecular dynamics (MD) simulation is performed to study the process of dislocation emission and crack propagation in a slab of Fe crystal with and without a porous layer on the surface of the crack. The results show that when there is a porous layer on the surface of the crack, the tensile stress induced by the porous layer can superimpose on the external applied stress and then assist the applied stress to initiate crack tip dislocation emission under lowered stress intensity KI, or stress. To respond to
the corrosion accelerated dislocation emission and motion, the crack begins to propagate under lowered stress intensity KI; resulting in SCC.
关键词:
Molecular dynamics simulation
