This paper proposes the finite element simplified fatigue analysis method for fatigue evaluation of the composite non-tubular joint structure of an offshore jacket subjected to wave loads. The skirt pile sleeve of the...This paper proposes the finite element simplified fatigue analysis method for fatigue evaluation of the composite non-tubular joint structure of an offshore jacket subjected to wave loads. The skirt pile sleeve of the offshore jacket, which had been in service, was taken as an example of the non-tubular joint structure. SACS software was used for global analysis of multi-directional wave loads for the jacket platform, and ALGOR software was used to build a finite element model, perform finite element analysis, post-process stress results for acquiring the stress range, and perform fatigue evaluation. The analysis results indicate that the extreme stress range is within the allowable stress range and meets the requirements of DNV code. That means the simplified fatigue analysis method is effective and can be used in fatigue design for the non-tubular joint structure of an offshore jacket.展开更多
The hot deformation behaviors of solution treated Mg-1.8Mn-0.4Er-0.2Al alloys were investigated by means of compression tests on Gleeble-1500 in strain rate range of 0.01-10s-1,deformation temperature range of 250-450...The hot deformation behaviors of solution treated Mg-1.8Mn-0.4Er-0.2Al alloys were investigated by means of compression tests on Gleeble-1500 in strain rate range of 0.01-10s-1,deformation temperature range of 250-450℃ and a true strain of 0.6.The constitutive relationships among flow stress,strain rate and deformation temperature were described by Arrhenius-type equations,based on the fact that the material constants could be calculated under a wide range of strains.The results show that the flow stress of the experimental alloy decreases with temperature increasing and strain rate decreasing.Under the experimental conditions,the products of constant α and n in the constitutive equation are stable within certain strains,and the deformation activation energy ranges from 160 to 220 kJ/mol.It is proved that the values of calculated flow stress are close to the experimental results with average error of 2.01%.展开更多
文摘This paper proposes the finite element simplified fatigue analysis method for fatigue evaluation of the composite non-tubular joint structure of an offshore jacket subjected to wave loads. The skirt pile sleeve of the offshore jacket, which had been in service, was taken as an example of the non-tubular joint structure. SACS software was used for global analysis of multi-directional wave loads for the jacket platform, and ALGOR software was used to build a finite element model, perform finite element analysis, post-process stress results for acquiring the stress range, and perform fatigue evaluation. The analysis results indicate that the extreme stress range is within the allowable stress range and meets the requirements of DNV code. That means the simplified fatigue analysis method is effective and can be used in fatigue design for the non-tubular joint structure of an offshore jacket.
基金Project(2008BA4036) supported by the Natural Science Foundation of Chongqing Science and Technology Commission, ChinaProject(081061130) supported by the National University Students Research Training Program and Sharing Fund of Chongqing University’s Large-scale Equipment
文摘The hot deformation behaviors of solution treated Mg-1.8Mn-0.4Er-0.2Al alloys were investigated by means of compression tests on Gleeble-1500 in strain rate range of 0.01-10s-1,deformation temperature range of 250-450℃ and a true strain of 0.6.The constitutive relationships among flow stress,strain rate and deformation temperature were described by Arrhenius-type equations,based on the fact that the material constants could be calculated under a wide range of strains.The results show that the flow stress of the experimental alloy decreases with temperature increasing and strain rate decreasing.Under the experimental conditions,the products of constant α and n in the constitutive equation are stable within certain strains,and the deformation activation energy ranges from 160 to 220 kJ/mol.It is proved that the values of calculated flow stress are close to the experimental results with average error of 2.01%.
