The main aim of the work was to investigate a simplified finite element simulation of the out-of-plane distortion caused by fusion butt welding. The thermal transient part of the simulation made use of a finite element analysis of the two-dimensional cross-section of the weld joint and the thermoelastic-plastic treatment was based on analytical algorithms describing transverse and longitudinal deformations, leading to predictions of transverse angular deformation and longitudinal contraction force. These results were then applied to a non-linear elastic finite element model to provide predictions of the final angular and overall deformations of the butt-welded plates. The validity of the simulation was investigated via full-scale tests on 4m x 1.4m x 5 mm steel plates, butt welded using a flux-cored Ar-CO₂ metal-inert gas process. Thermography and thermocouple arrays were used to validate the thermal transient computations and out-of-plane deformations were measured using displacement transducers for transient deformations and a laser scanning system to measure the profiles of the whole plates before and after welding. The results of six full-scale tests are given and comparison with the simulations shows that the procedure provides good prediction of the angular and overall out-of-plane deformations. Prediction accuracy requires account to be taken of initial shape, gravity loading, and support conditions.

Prediction and control of thermal distortion is particularly important for the design and manufacture of multiply stiffened welded structures. This study aimed to develop and experimentally validate a comprehensive simulation tool to predict distortion, with particular emphasis on out-of-plane deformation generated in double-sided fillet-welded attachments. Simulation was used to optimise the relative positions of a twin-arc configuration, to give minimum out-of-plane deformation consistent with reasonable production time for single stiffener, double-fillet attachments. The critical buckling load of the structure was approached and exceeded as the arcs were brought closer and simulation allowed the influence of this factor to be determined.

There are limited experimental data on VHCF for structural steels for >${10}^7$ cycles. Unalloyed low-carbon steel S275JR+AR is a common structural material for the heavy machinery in minerals, sand and aggregate applications. The purpose of this research is to investigate the fatigue behaviour in the gigacycle domain (>${10}^9$ cycles) for S275JR+AR grade steel. This is achieved using accelerated ultrasonic fatigue testing in as-manufactured, pre-corroded and non-zero mean stress conditions. As internal heat generation is a massive challenge for ultrasonic fatigue testing of structural steels which exhibit a pronounced frequency effect, effective temperature control is crucial for implementation of testing. The frequency effect is assessed by comparing the test data at 20 kHz and 15–20 Hz. Its contribution is significant, as there is no overlap between the stress ranges of interest. The obtained data are intended to be applied to the fatigue assessments of the equipment operating at the frequency for up to ${10}^{10}$ cycles over years of continuous service.

Results of a parametric finite element analysis investigation of stress concentration at radial crossholes in pressurized cylinders are presented in numerical and graphical form. The analysis shows that the location of maximum stress does not generally occur at the junction between the bores, as is commonly supposed, but at some small distance up the crosshole from the junction. Maximum stress concentration factors (SCFs) are defined on the basis of the maximum principal stress, von Mises equivalent stress, and stress intensity. Three-dimensional plots of the SCF against the cylinder radius ratio b/a and the crosshole-to-main-bore-radius ratio c/a are presented. The SCFs were found to vary across the range of geometries considered with local minima identified within the parameter range in most cases. The results therefore allow designers to select optimum b/a and c/a ratios to minimize stress concentration in real problems.