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Fatigue failure caused by stress concentrations in tubular welded joints is observed in off shore platforms subjected to cyclic loading in corrosive marine environments. In some junctions, the stress concentration can induce a stress thirty times the nominal stress, and increase the risk of fatigue failure in tubular joints. Therefore, it is necessary to accurately assess the intensity of the stress concentrations to effectively deal with the problem of fatigue damage and lead to reliable tubular joints. This work aims to study the stress distribution and location of the "hot" spots in a Twelded tubular structure subjected to a combined loading of tension and bending (in-plane bending, out of plane bending and traction) to better simulate the actual loading.

Offshore structures are generally constructed as frameworks of tubular members. The tubular joints should be designed to allow the full post yield or post buckled capacity of the members. However, design guidelines for ultimate strength capacity of these joints are based exclusively upon compilations of test data for simple configurations under simple loading conditions. A methodology based upon the finite element method is presented for analytically predicting the ultimate strength of arbitrary tubular joints. Eight node, isoparametric, curved shell elements were used for the majority of the tubular joint model. Twenty node, isoparametric, solid elements were used to capture the three‐dimensional stress state at the shell intersection while fifteen node, isoparametric, wedge elements modelled the weld profile. Solid‐shell transition elements provided the connection between the three‐dimensional solid elements and the surface based shell elements. Non‐linearities were included via an elastoplastic material model with isotropic strain hardening and the updated Lagrangian approach for finite deflections and rotations. Several experimental tubular joint analyses were reproduced to validate the analytical procedure. Non‐linear finite element analysis was shown to be a practical approach for the evaluation and extension of current design procedures for tubular joints.

EVER since the beginning of aircraft construction sheet metal fittings have been made by means of oxy‐acetylene welding; usually in the form of fittings connecting parts of plywood fuselages or of wooden wings. Later, strut fittings followed in which U‐shaped sheets or flanges were welded to tubes. Control‐gear parts were made from tubes, bushes and sheet webs. Afterwards, whole fuselages and control components, such as tail plane structures and elevators, became welded tubular structures. All attachments required for engines, undercarriages, wings and installed components were welded up, according to the design practice preferred.

WHEN metal parts are exposed to alterations of temperature, their outer dimensions undergo a change. With rising temperatures metals expand, with falling temperatures they contract. If different temperatures exist within one and the same metal member, internal stresses begin to act, causing a deformation of the component and thus setting up internal strains. Cracks, buckling, distortion and shrinkage are the external results of such strains.

In the present work, an analysis of influence of the notch on the toughness of material K_I is presented. A notched plate made out of structural steel is considered and subjected to uniformly tensile loading. Different values of angle and notch radius were selected. The material is assumed to be elastic perfectly plastic and the analysis was made according to a local approach defined by the volumetric approach. The parameters of the volumetric approach are the effective distance, effective stress and relative stress gradient and are determined by using the finite element method (F.E.M). The variation of the weight function affects the calculation of effective stress. The results obtained are confronted with models of Irwin and Creager - Paris. The results obtained show that for small radii, the stress intensity factor calculated by the weight function unit is close to those obtained by the models of Irwin and Creager-Paris. The increasing in the notch angle influences on the assessment of fracture toughness.

To obtain better fatigue resistance for marine engineering equipment welded joints in the design stage, the design method of the marine engineering equipment welded joint design stage needs to be studied.

Based on the structural stress theory, a design method of the marine engineering equipment welded joints with better fatigue performance is proposed. The effectiveness of the method is demonstrated through the simulation analysis and fatigue test of typical marine engineering equipment welded joints.

Methods based on the theoretical advantages of structural stress and the principle of ensuring that the welded joint has a low degree of stress concentration.

The design method of marine engineering equipment welded joints proposed in this study provides a set of operable design routes for technicians, which can better meet the needs of engineering applications.

This study investigates the fitting techniques for notch fatigue curves, seeking a more reliable method to predict the lifespan of welded structures.

Building on the fatigue test results of butt and cruciform joints, this research delves into the selection of fitting methods for the notch fatigue curve of welded joints. Both empirical formula and finite element methods (FEMs) were employed to assess the notch stress concentration factor at the toe and root of the two types of welded joints. Considering the mean stress correction and weld misalignment coefficients, the notch fatigue life curves were established using both direct and indirect methods.

An engineering example was employed to discern the differences between the direct and indirect approaches. The findings highlight the enhanced reliability of the indirect method for fitting the fatigue life curve.

While the notch stress approach is extensively adopted due to its accurate prediction of component fatigue life, most scholars have overlooked the importance of its curve fitting methods. Existing literature scantily addresses the establishment of these curves. This paper offers a focused examination of fatigue curve fitting techniques, delivering valuable perspectives on method selection.

Basically, connections are used to transfer the force supported by structural members to other parts of the structure. The flush end-plate bolted beam to column connection is one type that has been widely used because of its simplicity in fabrication and rapid site erection. The purpose of this study is to determine the moment-rotation curve, moment of resistance (MR) and mode of failure, and the results were compared with existing results for normal flat web connections.

In this study, the connection modeled was the flush end-plate welded with triangular web profile (TriWP) steel beam section and then bolted to a UKC column flange. The bolted flush end-plate semi-rigid beam to column connection was modeled using finite element software. The specimen was modeled using LUSAS 14.3 finite element software, with dimensions and parameters of the finite element model sizes being 200 × 200 × 49.9 UKC, 200 × 100 × 17.8 UKB and 200 × 100 with a thickness of 20 mm for the endplate.

It can be concluded that the MR obtained from the TriWP steel beam section is different from that of the normal flat web steel beam by 28%. The value of MR for the TriWP beam section is lower than that of the normal flat web beam section, but the moment ultimate is higher by 21% than the normal flat web. Therefore, it can be concluded that the TriWP section can resist more acting force than the normal flat web section and is suitable to be used as a new proposed shape to replace the normal flat web section for a certain steel structure based on the end-plate connection behavior.

As a result, the TriWP section has better performance than the flat web section in resisting MR behavior.

THE subject of this article is different from others in our series and offers less chance of the direct comparison of methods, because the size of the machine is great and the quantity built comparatively small. In another important respect it differs in that, hitherto, the approach has been from the point of view of the way in which a firm has laid itself out to produce one type, whereas in this case, it is the general working methods of the firm and its system of construction which is considered. It should be borne in mind throughout that the demand for flying‐boats, even military types, is limited, and jigs have to be large and costly to accommodate the big components, so that, to a certain extent, each boat is individually built. This individuality problem spreads, of course, even to the planning department; for each type of machine represents many thousands of parts, of which, at best, only a few off each will be required.

This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper contains references to papers, conference proceedings and theses/dissertations on the subject that were published between 1977‐1998. The following topics are included: ceramics – material and mechanical properties in general, ceramic coatings and joining problems, ceramic composites, ferrites, piezoceramics, ceramic tools and machining, material processing simulations, fracture mechanics and damage, applications of ceramic/composites in engineering; glass – material and mechanical properties in general, glass fiber composites, material processing simulations, fracture mechanics and damage, and applications of glasses in engineering.