Volume 2 Issue 2
Authors: Ye. Deryugin
Abstract: The effect of structural and phase state of material and of strain rate on the fracture mechanisms was studied for commercial ultrafine grain titanium VT1-0 and ultrafine grain titanium alloy VT6. The experimental evidence validates the postulate of physical mesomechanics that fracture processes occurring in the nonequilibrium ultrafine grain structure should be addressed in terms of nonequilibrium thermodynamics.
Keywords: Ultrafine Grains; Strain Localization; Fracture; Stress Intensity Factor
Authors: Wenjie Niu
Abstract: The classical analytical elastic solution for concrete dam is assumed that the bottom extends to infinitely far. However, real dam in nature is not that high. This paper intends to investigate whether this classical analytical solution could be applied to an idealized concrete dam where the dam foundation elasticity is infinite or can say extremely rigid. Results indicate that when adjacent to the bottom boundary line of the dam superstructure, the analytical solution and FEM solution deviate with each other. The analytical solution and FEM solution agree well with each other when the studied point is very far away from the bottom boundary line. All the results indicate that Saint-Venant’s Principle applied to the bottom boundary line of concrete dam for the analytical solution. The dam superstructure bottom boundary stress condition is not known when to obtain the classical analytical solution in the past. However in fact, the dam superstructure bottom boundary stress condition must affect the stress distribution in the dam superstructure. But the resultant forces of the stresses on the dam superstructure bottom boundary from the classical analytical solution satisfy the equilibrium equation of the dam superstructure under all external forces. This is just the merit and defect of the Saint-Venant’s Principle which loosens the boundary stress condition to obtain an approximate solution which is almost correct when the studied point is far away from the loosened boundary and always wrong when the studied point is near the loosened boundary. It means that only when the studied point is very far away from the bottom boundary line of a dam, the obtained stress distribution results from the classical analytical elastic solution are acceptable.
Keywords: Classical Analytical Elastic Solution; Concrete Dam; Saint-Venant’s Principle; FEM Solution; Bottom Boundary Line
Authors: P. Ponnusamy; R. Selvamani
Abstract: The longitudinal waves in a homogeneous transversely isotropic rotating solid cylinder immersed in an in viscid fluid is studied using the linearized, three-dimensional theory of elasticity. The equations of motion of solid and fluid are respectively formulated using the constitutive equations of a transversely isotropic cylinder and the constitutive equations of an in viscid fluid. The solution of the frequency equations are obtained by Chebyshev polynomials series using the geometric boundary conditions. The computed non-dimensional frequencies are presented in the form of dispersion curves for the material Zinc.
Keywords: Solid Cylinder Loaded with Fluid; Free Vibration of Transversely Isotropic Cylinder; Wave Propagation in a Rotating Cylinders; Chebyshev Polynomials
Authors: Hao Wu; Zhibo Li; Zhiwei Tong; Hang Chen
Abstract: When conducting the Real-time monitoring of deep foundation pit displacement, the monitoring equipment, such as the displacement sensor, is embedded inside the inclinometer pipe which is in the mechanical probe. Since the chips and sensor are galvanical, waterproof, pressure prevention and sensitivity become the major problems in this project. However, the three factors, sealing of waterproof, sensitivity of the mechanical devices and portable properties interact and restrict each other in the actual practice, finding a way to improve the coordination among is vital. In this paper, the connecting sliding mechanism which contains stiffness coefficient and mechanical springs, fine thread set on the ends of the sleeve and end cap in the mechanical probe have solved the problems efficiently, and the project operated excellently by this way.
Keywords: Deep Foundation Pit; Inclinometer Tube; Mechanical Probe; Sealing; Sensitivity; the Displacement Sensor