Analysis of Stress and Strain Fields of Laser Cladding Process on Ring Circular Orbit

The cracking of coatings and the deformation of base frustrate the application of laser cladding technology especially on surface of the ring circular orbit.In order to solve the two problems above,the stress and strain fields of the laser cladding process on the ring circular orbit were analyzed through the finite-element method,based on the temperature field.The wedge module of the ring circular ring was the subject investigated. The calculating results show that during the cladding process the crank point tends to generate the transversal crack;the centre point on the coating/base interface tends to generate longitudinal crack;the intersecting edge of the coating and base tends to generate toe crack.Moreover,the cracking tendency of the outer marginal point is obviously greater than that of the inner marginal point.The rather high stress appears at the border position where the constraint exists,and the stress on the point in front of molten pool under the range of laser irradiation is large as well.And the displacement becomes larger as the cladding process proceeds.

Stress-strain characteristics of linear friction welding of TC11 and TC17 alloys

Abstract Transient stress and strain fields of dissimilar titanium alloys （TCll and TC17 ） joint during linear friction welding （ LFW） were investigated by a two-dimensional model with ABAQUS/Explicit. The results showed that in the X-axis, the maximum compressive stress of 850 MPa occurred in the center zone of friction interface , and the maximum tensile stress of 190 MPa distributed at the flash; in the Y-axis, the maximum compressive stress of 1 261 MPa located at the junction region between the welding fixture and edge of the specimen, and the maximum tensile stress of 320 MPa distributed in the connecting portion between the flash and edge of the specimen. In addition, areas of plastic strain increased gradually during welding process. In the X-axis, tensile strain mainly existed at the heads of the specimens; in the Y-axis, compressive strain mainly occurred at the heads of the specimens.

THE EXPRESSION OF STRESS AND STRAIN AT THE TIP OF NOTCH IN REISSNER PLATE

In this paper, the eigenequation of notch in Reissner plate is derived by the eigenfunction method. Eigenvalues of different notches with different angles are calculated by Muller iteration method. The expression of stress and strain at the tip of notch in Reissner plate is obtained.

The Expression of Stress and Strain at the Tip of Three-Dimensional Notch

The singularity of stress and strain at the tip of three-dimensional notch isanalysed by the power expansion method .the eigenquation of the notch is gainedthrough the boundary conditions of the notch, the eigenvalues under different innerangles of the notch are obtained, the expression of stress and strain at the tip of thenotch is finally derived .

Numerical simulation of tectonic stress and strain rate fields in the northeastern margin of the Tibetan Plateau in association with major fault zones

A series of large strike-slip and thrust faults have developed in the northeastern margin of the Tibetan Plateau since the Late Cenozoic,with strong and active tectonic activity and frequent occurrences of large earthquakes.Modulation of regional tectonic stress distribution,strain fields,and seismic hazards has not been well studied.This study introduces a three-dimensional viscoelastic finite element numerical model to calculate crustal stress and strain rate fields under current tectonic loading.The preliminary results show that the direction of the horizontal principal compressive stress rate and compressive horizontal principal strain rate in the northeastern margin of the Tibetan Plateau rotate clockwise as a whole,and this rotation is more significant in the southeast direction because of the block of the Alxa and the Ordos blocks.The NE-SW horizontal principal compressive stress rate and SE horizontal tensile stress rate dominate the entire study region.The maximum value of the horizontal principal compressive strain rate at a depth of 0 km in the model is approximately 4×10^(-8)yr^(-1)near the East Kunlun fault and is smaller in the stable Alxa and Ordos blocks at approximately 1×10^(-8)yr^(-1).The calculated regional stress state is in good agreement with the actual focal mechanism solution,indicating that strike-slip and thrust stress fields dominate the northeastern margin of the Tibetan Plateau.The Altyn Tagh,East Kunlun,and Haiyuan faults demonstrate that the maximum shear strain rate gradually decreases eastward,and the decrease in the maximum shear strain rate value is absorbed by orogenic uplift and crustal shortening at its boundaries.The western section of the Altyn Tagh fault,west-to-middle sections of the East Kunlun fault,and west-to-middle sections of the Haiyuan fault will have high seismic hazards in the future.

Numerical simulation of DE- GMAW of magnesium alloy cylinder

Double-electrode gas shielded arc welding （ DE - GMAW） was used to weld the magnesium alloy cylinder with the diameter of 200 mm and the thickness of 6 mm. In order to study the residual stress distribution of AZ31B magnesiunl alloy welding point, numerical sinmlation of welding temperature field, stress field and residual stress were carried out by MSC. mare software. The results show that the residual stress in the weld and the heat affected zone is large, and with the increase of the distance away from the weld center, the residual stress decreases. In most areas, the longitudinal residual stress is greater than the transverse residual stress （except for the inside and outside surfaces of the weld） , all of which provides theoretical support for the study of magnesiunl alloy welding residual stress.

Analysis of bulging for high speed continuous casting

In order to research the temperature distribution and mechanical deformation of slab bulging during high speed continuous casting, mathematical models have been developed to analyze the thermal and mechanical behavior of the slab. The thermal history of the slab has been predicted by a two-dimensional transient finite element heat transfer model, whose results serve as the input to the stress model. The stress model has been formulated for a two-dimensional longitudinal plane. In this case,the maximum tensile strain during the bulging process is located at the solidification fi＇ont just past the top of the upstream roll,which may contribute to crack formation. The maximum tensile stresses are located at the cold surface in the middle of the two back-up rolls ,just at the point of the maximum bulging. Stresses near the solidification fi＇ont are small because of the high temperatures which produce lower elastic modulus values. Finally,the effect of the casting speed on the bulging deformation is discussed.