Influence of Combined Mean Stresses on Lifetime under High-Cycle Fatigue

This study builds on experiments with different combinations of tension and torsion pre-stresses which were published in [1]. The results were particularized by new tests for combined pre-stresses in normal and shear components. The ratio between normal and shear pre-stresses was 3:2 in agreement with the coefficient kc. The same material structural low carbon ČSN 41 1523.1 steel after normalization annealing was used for specimens. The results were compiled and displayed in a three-dimensional Haigh diagram with normalized coordinates and interlaid by corresponding terminal lines.

Using Depth-Normalized Coordinates to Examine Mass Transport Residual Circulation in Estuaries with Large Tidal Amplitude Relative to the Mean Depth

Residual (subtidal) circulation profiles in estuaries with a large tidal amplitude-to-depth ratio often are quite complex and do not resemble the traditional estuarine gravitational circulation profile. This paper describes how a depth-normalized σ-coordinate system allows for a more physical interpretation of residual circulation profiles than does a fixed vertical coordinate system in an estuary with a tidal amplitude comparable to the mean depth. Depth-normalized coordinates permit the approximation of Lagrangian residuals, performance of empirical orthogonal function (EOF) analysis, estimation of terms in the along-stream momentum equations throughout depth, and computation of a tidally averaged momentum balance. The residual mass transport velocity has an enhanced two-layer exchange flow relative to an Eulerian mean because of the Stokes wave transport velocity directed upstream at all depths. While the observed σ-coordinate profiles resemble gravitational circulation, and pressure and friction are the dominant terms in the tidally varying and tidally averaged momentum equations, the two-layer shear velocity from an EOF analysis does not correlate with the along-stream density gradient. To directly compare to theoretical profiles, an extension of a pressure–friction balance in σ coordinates is solved. While the barotropic riverine residual matches theory, the mean longitudinal density gradient and mean vertical mixing cannot explain the magnitude of the observed two-layer shear residual. In addition, residual shear circulation in this system is strongly driven by asymmetries during the tidal cycle, particularly straining and advection of the salinity field, creating intratidal variation in stratification, vertical mixing, and shear.

COMPUTATIONALLY EFFICIENT TECHNIQUE FOR THE SOLUTION OF TIMOSHENKO BEAM AND MINDLIN-REISSNER PLATE PROBLEMS USING THE METHOD OF FINITE SPHERES

In this paper we discuss the application of the method of finite spheres (MFS) to the solution of shear deformable beam and plate problems. A computationally efficient technique is presented in which the integration points and weights are generated using a genetic algorithm and stored in a lookup table using normalized coordinates much like a table of Gauss integration points and weights. This technique offers a significant reduction of computational time while maintaining accuracy.