Weld defect frequency, size statistics and probabilistic models for ship structures

Amirafshari, Peyman; Barltrop, Nigel; Wright, Mark; Kolios, Athanasios

doi:10.1016/j.ijfatigue.2020.106069

Cited by 25 publications

(11 citation statements)

References 14 publications

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“…The welds are generally a weak point of the structure, due to the presence of possible crack-like defects along with high stress concentration effects and tensile residual stresses caused by the thermal welding process itself, so a fatigue design is required (Figure 3) for the fatigue life prediction of ship welded details [2][3][4]. The offshore infrastructure has extended its application from the oil and gas industry to the emerging offshore wind industry.…”

Section: Introductionmentioning

confidence: 99%

“…Figure 4 shows the crack at the weld seam of an offshore platform [9]. The welds are generally a weak point of the structure, due to the presence of possible crack-like defects along with high stress concentration effects and tensile residual stresses caused by the thermal welding process itself, so a fatigue design is required (Figure 3) for the fatigue life prediction of ship welded details [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…For thickness below 8 mm, UT cannot be used, so RT, able to detect nonplanar defects, should be used in conjunction with MPT or DPT. The weld defect length data, mainly collected by RT from the inspection of two ships, were investigated and analyzed in [3]. An overview of weld quality control and assurance of welded structures subjected to fatigue loading was provided by Stenberg et al [16] The ships can contain hundreds of kilometers of weld lines, so only a limited number of welded joints can be inspected, and the Classification Societies specify a number of checkpoints for the inspection.…”

Section: Introductionmentioning

confidence: 99%

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Review of Fatigue Assessment Approaches for Welded Marine Joints and Structures

Corigliano

Crupi²

2022

Metals

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Welded joints are widely used in many sectors and represent the main joining technique also in the marine industry. The welded joints are sites of high stress concentrations and are subject to severe conditions for the marine environment. The design of marine welded joints has to consider the effects from wave loads, ship motions and loading/unloading operations and corrosion effects. The aim of this scientific work is to discuss about the state of the art of the standards and the approaches for predicting the fatigue life of welded joints used for the marine industry. Several approaches are examined in order to provide an overview and highlight the advantages and limitations of each method. Furthermore, recent advances in welding of dissimilar metals and autonomous welding are considered.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Review of Fatigue Assessment Approaches for Welded Marine Joints and Structures

Corigliano

Crupi²

2022

Metals

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“…Welding is an important step in hull assembly and an important factor affecting the quality of the hull. [4][5][6]21 Many stations and processes in the processing of sub-assemblies and unit-assemblies in shipbuilding must rely on welding. Most of the subassemblies and unit-assemblies of shipbuilding enterprises still use the traditional manual welding method, which has low welding efficiency, low degree of automation and high labor intensity.…”

Section: Introductionmentioning

confidence: 99%

Research on trajectory planning of sub-assembly and unit-assembly robot in shipbuilding industry

Yang

et al. 2022

Advances in Mechanical Engineering

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In shipbuilding, welds in sub-assemblies and unit-assemblies are long and various type. The robot arm needs the gantry movement to cooperate with the welding operation. However, there are joint redundancy and double-arm coordination problems, which cause difficulties in the welding trajectory planning. This paper proposes a strategy of decoupling the dual-arm system into a single-arm system for separate planning and prioritizing joint motion, and conducts welding trajectory planning research based on Matlab’s Simscape Multibody. Firstly, the 3D model of the welding workstation is established, its structure, the operation mode of the joint link and the degree of freedom are analyzed. The 17-DOF welding workstation is decoupled into a single-arm 9-DOF system, a kinematic model is established, kinematic analysis is carried out. The Matlab robot toolbox is used for simulation verification. Then the discretization of weld types and poses in sub-assemblies and unit-assemblies workpieces is analyzed. Finally, the welding workstation and workpiece model are imported into Simscape Multibody of Matlab to simulate the trajectory planning of different types of welds. The simulation results prove the effectiveness of the strategy and have certain reference significance for on-site welding in shipbuilding.

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“…Ship hull structures consist of plating connected to longitudinal and transverse members by welded joints, which are sites of high stress concentrations, and undergo fatigue loading, which, combined with weld defects, can cause the failure of the hull structures. The defect number and the size statistics of welded joints in ship hull construction were investigated by analyzing nondestructive technique (NDT) data collected from inspection of two ships and analyzed using the maximum likelihood estimate (MLE) [27]. It was found that hybrid laser-arc welding (HLAW) process has significantly better quality in terms of defect occurrence and, consequently, the fatigue strength compared to flux-cored arc welding (FCAW) and submerged arc welding (SAW).…”

Section: Introductionmentioning

confidence: 99%

Influence of Weld-Porosity Defects on Fatigue Strength of AH36 Butt Joints Used in Ship Structures

Crupi

Guglielmino

Marinò

2021

Metals

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Experimental tests were carried out to assess the fatigue strength of four types of welded joints, made of AH36 steel and used for ship structures. The joints differ for the presence of weld defects and for the thickness value. Fatigue tests were carried out applying axial cyclic loads at a frequency of 20 Hz and at a stress ratio R = 0.5. The temperature e increment of the specimen surface was detected during the load application by means of an infrared camera. The analysis of the thermographic images allowed the assessment of both the fatigue strength of the welded joints, applying the rapid thermographic method, and the S-N curve by the energy approach. Moreover, 3D computed tomography was used for the analysis of the defective welded joints.

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Weld defect frequency, size statistics and probabilistic models for ship structures

Cited by 25 publications

References 14 publications

Review of Fatigue Assessment Approaches for Welded Marine Joints and Structures

Review of Fatigue Assessment Approaches for Welded Marine Joints and Structures

Research on trajectory planning of sub-assembly and unit-assembly robot in shipbuilding industry

Influence of Weld-Porosity Defects on Fatigue Strength of AH36 Butt Joints Used in Ship Structures

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