scholarly journals Simulation of peak tension loads in Subsea power cables during installation

2021 ◽  
Vol 1201 (1) ◽  
pp. 012010
Author(s):  
L Okkerstrøm ◽  
O T Gudmestad ◽  
E Pedersen

Abstract At present, most of the insurance claims in the offshore wind industry are due to cable failures where a large percentage occurs during the installation of the array and export cables. As the reliability of the cables depends on the location and installation method, it is important to map the risks involved, which can compromise the cable’s integrity in individual projects. This paper presents sensitivity analyses conducted on crucial parameters in the cable laying process, with an objective of successful installation of subsea power cables without any damages to the cable. The analyses focus on the peak tension loads with reference to key parameters as cable self-weight and laying geometry, as well as the cable deployment position on the installation vessel. Finite element analyses were conducted with both static forces and dynamic forces for irregular vessel motions, by the aid of the well-tested software OrcaFlex.

Author(s):  
S. Thöns ◽  
M. H. Faber ◽  
W. Rücker

This paper establishes the model basis regarding the ultimate limit state consisting of structural, loading, and probabilistic models of the support structure of offshore wind energy converters together with a sensitivity study. The model basis is part of a risk based assessment and monitoring framework and will be applied for establishing the “as designed and constructed” reliability as prior information for the assessment and as a basis for designing a monitoring system. The model basis is derived considering the constitutive physical equations and the methodology of solving these which then in combination with the ultimate limit state requirements leads to the specific constitutive relations. As a result finite element models based on shell elements incorporating a structural and a loading model are introduced and described in detail. Applying these models the ultimate capacity of the support structure and the tripod structure are determined with a geometrically and materially nonlinear finite element analysis. The observed failure mechanisms are the basis for the definition of the ultimate limit state responses. A probabilistic model accounting for the uncertainties involved is derived on the basis of literature review and measurement data from a prototype Multibrid M5000 support structure. In combination with the developed structural and loading models, sensitivity analyses in regard to the responses are performed to enhance the understanding and to refine the developed models. To this end, as the developed models necessitate substantial numerical efforts for the probabilistic response analysis predetermined designs of numerical experiments are applied for the calculation of the sensitivities using the Spearman rank correlation coefficient. With this quantification of the sensitivity of the random variables on the responses including nonlinearity the refinement of the model is performed on a quantitative basis.


1997 ◽  
Vol 8 (1) ◽  
pp. 90-104 ◽  
Author(s):  
T.W.P. Korioth ◽  
A. Versluis

In this paper, we provide a review of mechanical finite element analyses applied to the maxillary and/or mandibular bone with their associated natural and restored structures. It includes a description of the principles and the relevant variables involved, and their critical application to published finite element models ranging from three-dimensional reconstructions of the jaws to detailed investigations on the behavior of natural and restored teeth, as well as basic materials science. The survey revealed that many outstanding FE approaches related to natural and restored dental structures had already been done 10-20 years ago. Several three-dimensional mandibular models are currently available, but a more realistic correlation with physiological chewing and biting tasks is needed. Many FE models lack experimentally derived material properties, sensitivity analyses, or validation attempts, and yield too much significance to their predictive, quantitative outcome. A combination of direct validation and, most importantly, the complete assessment of methodical changes in all relevant variables involved in the modeled system probably indicates a good FE modeling approach. A numerical method for addressing mechanical problems is a powerful contemporary research tool. FE analyses can provide precise insight into the complex mechanical behavior of natural and restored craniofacial structures affected by three-dimensional stress fields which are still very difficult to assess otherwise.


2016 ◽  
Author(s):  
Patrick Gilman ◽  
Ben Maurer ◽  
Luke Feinberg ◽  
Alana Duerr ◽  
Lauren Peterson ◽  
...  

Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.


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