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Shintaro Hokada

Publications and source records attributed to Shintaro Hokada.

4 recordsLinked to original sources

Revisiting Stress Analysis in a Three-Dimensional Elastic Hollow Sphere under Uniaxial Compression via the Inverse Laplace Transform Expressions within an Elastodynamic Framework

The stress analysis of a three-dimensional elastic hollow sphere subjected to uniaxial compression is revisited, employing an elastodynamic framework. Through the application of the Laplace transform, the scalar and vector potentials of displacement are expanded, facilitating a detailed exploration of the system's mechanical behavior. The static solutions for displacement and stress distributions are derived in the long-time limit, which reveal key insights into the response of the elastic hollow sphere. Notably, on the inner surface, certain quantities exhibit a peak at the point where the angle between the compressive force and the point on the surface becomes perpendicular, indicating localized stress concentration. These findings provide a robust analytical approach for understanding and predicting the behavior of elastic hollow spheres under uniaxial loading, with implications for material science and structural engineering.

physics.class-ph

Inverse Reconstruction of Moving Contact Loads on an Elastic Half-Space Using Prescribed Surface Displacement

This study investigates the elastic response of a two-dimensional semi-infinite medium subjected to a moving surface load with a prescribed displacement profile. As a fundamental step, we derive analytical Green's functions for the displacement and stress fields generated by a point load traveling at a constant velocity along the surface, explicitly incorporating elastodynamic effects through Mach number dependence. These moving-load solutions serve as building blocks for constructing more general loading scenarios via linear superposition. Based on Green's functions, an inverse problem is formulated to reconstruct the unknown surface traction responsible for a given surface displacement. The inverse analysis is performed through a Fourier-domain inversion with regularization, which enables a direct and computationally efficient determination of the contact pressure without iterative forward simulations. This framework is applied to a rigid wheel-ground contact problem, where the imposed displacement is dictated by the wheel geometry. The reconstructed surface traction exhibits a smooth, symmetric distribution within the contact region, while the resulting subsurface stress fields are obtained in closed analytical form and involve dilogarithm functions. The principal stress difference reveals characteristic spatial patterns similar to photoelastic fringes, and their asymmetry increases with the Mach number, reflecting the dynamic nature of the moving contact.

physics.class-ph

Stress Analysis of a Square Elastic Body Under Biaxial Loading Using Airy Stress Functions

This study presents an analytical investigation of stress distributions in square-shaped elastic bodies subjected to concentrated compressive loads under uniaxial and biaxial conditions. By employing the Airy stress function method, we derive closed-form solutions that satisfy the governing biharmonic equation and the prescribed boundary conditions along the edges of the square domain. The stress components are expressed as series expansions, with coefficients determined to enforce boundary constraints. In the uniaxial compression case, the resulting stress fields exhibit strong agreement with photoelastic fringe patterns previously observed in experimental studies. For biaxial loading, the solution represents a superposition of two orthogonal compression scenarios, producing spatial variations in the principal stress difference depending on the location within the domain.

physics.class-ph

Proposal for fast computational method for Hertzian contact theory

Fast computational method for Hertzian contact theory is proposed. An incremental formula is introduced to calculate the ellipticity of the contact disk when two elastic bodies are in contact. This method can determine the ellipticity with good accuracy in a small number of iterations is reported. This method is also shown to be applicable from the case of a near perfect circle to the case where the major diameter is sufficiently long compared to the minor diameter.

physics.class-ph