Stress field

About: Stress field is a research topic. Over the lifetime, 11926 publications have been published within this topic receiving 226417 citations.

Laser shock peened rotor components for turbomachinery

Abstract: Turbomachinery rotor components having a metallic body with at least a portion of the body subject to a tensile stress field due to centrifugal and thermal growth induced forces generated by the rotor when the rotor is rotating, at least one stress riser in the stress field portion that causes stress concentration when the rotor is rotating, and at least one region of the component around the stress riser having deep compressive residual stresses imparted by laser shock peening (LSP).

Fracture initiation at three-dimensional bimaterial interface corners

Abstract: We propose an approach to correlate fracture initiation at three-dimensional bimaterial interface corners based on the existence of a universal singular stress field in the context of linear elasticity. The idea is to correlate fracture initiation with critical values of the stress intensities of the singular fields calculated from a linear elastic stress analysis. The approach is in the spirit of interface fracture mechanics but applicable to a different class of problems, specifically, situations without a preexisting crack and situations where subsequent crack propagation does not necessarily occur along the interface. In order to validate the proposed approach, we designed and fabricated a series of aluminum/epoxy bimaterial specimens that possess well-defined three-dimensional interface corners. They consist of two perfectly bonded square prisms with varying interface dimensions and surface finishes. The specimens were loaded in four-point flexure until fracture initiated at the three-dimensional interface corner. The nominal stress at failure varied significantly with interface dimensions, thus invalidating its use as a fracture criterion. From a rigorous asymptotic analysis of the three-dimensional interface corner stress state, we determined the order of the singularity and the angular variation of the stress and displacement fields. We determined the corresponding stress intensities via full-field finite element analyses of the aluminum/epoxy specimens. Although the measured failure stress varied significantly with interface dimensions, the corresponding critical stress intensity did not, although as expected it varied with interface surface finish. These findings support the use of critical stress intensities to correlate fracture initiation at three-dimensional bimaterial interface corners.

Redistribution of recent collision push and ridge push in Central Europe: insights from FEM Modelling.

Abstract: SUMMARY 2-D elastic finite element models of the recent stress field of Central Europe are built to evaluate the loads exerted on the continental boundary and the magnitude of tectonic stresses within the continental part of the plate. The models comprise 24 tectonic blocks (their stiffness is either constant throughout the model or varies from block to block), 16 fault zones and 12 geologically significant boundary segments. We have obtained a relatively unique balance of external tectonic forces by (1) careful adjustment of calculated stress directions and regimes to complex pattern of stress from data and (2) by calibration with gravitational potential energy. A high level of compression (ca. 9 × 10 12 Nm −1 ) exerted to the short Ionian side of the Adriatic indenter is crucial for the stress-field pattern in Central Europe. The Adria microplate rotates due to eccentricity between the Africa push from the south and the Alpine buttress to the north. A free boundary of the Apennines does not contribute significantly to this motion. Kinematics of this indenter is controlled by friction on the Dinaric suture, which, in turn is decisive for strain-energy distribution between the Alpine and the Pannonian domains. The predicted pronounced extension in the Greece‐Aegean segment (2.5 × 10 12 Nm −1 ) implies active pull transferred from the Hellenic subduction zone. This extension releases stress in the Balkan‐Pannonian region and enables the eastward escape of tectonic blocks in front of advancing Adria. Significant changes of tectonic push trends are found along the Black Sea‐ Caucasus boundary segment and at the European passive margin from the North Sea to the Arctic Ocean. Differential stresses in Central Europe are estimated in the range of 10‐60 MPa when averaged over the 30‐80-km-thick mechanically heterogeneous lithosphere. The maximum stiffness contrast across the model is predicted to be of one order of magnitude. Apparent friction coefficients of fault zones differ between the North European part of the plate (0.4‐0.7), the Pannonian region (0.15‐0.25) and the Dinaric suture (0.55).