Ultimate Strength and Post-Ultimate Strength Behavior of Damaged Tubular Members in Offshore Structures

1988 ◽  
Vol 110 (3) ◽  
pp. 254-262 ◽  
Author(s):  
T. Yao ◽  
J. Taby ◽  
T. Moan
Keyword(s):  
Boundary Conditions ◽  
Ultimate Strength ◽  
Parametric Study ◽  
Structural Unit ◽  
Offshore Structures ◽  
Experimental Results ◽  
Lateral Deflection ◽  
Various Boundary Conditions ◽  
Unit Model ◽  
Strength Behavior

An idealized structural unit model is constructed to represent the pre and post-ultimate strength behavior of a damaged tubular member with various boundary conditions subjected to various end loads. Local denting and overall permanent lateral deflection are considered as a damage. The calculated results using this model are compared with a large number of previous and new experimental results. A parametric study regarding the influence of damages on the ultimate strength of tubular members is also performed.

Investigation on the Post-Ultimate Strength Behaviour of Sandwich Plate

2014 ◽  
Author(s):  
Wei Wang ◽  
Weijun Xu ◽  
Xiongliang Yao ◽  
Nana Yang
Keyword(s):  
Ultimate Strength ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Sandwich Plate ◽  
Experimental Results ◽  
Sandwich Plates ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Strength Behavior ◽  
Simulation Results

This paper focuses on the post-ultimate strength behavior of sandwich plates. With widely application of the laminate on the ship and offshore structures, the post-ultimate strength behavior is becoming more important for safety evaluation of structures. Since the post-ultimate strength behavior can reflect the collapse extent of sandwich plate when subjected to extreme loads. A sandwich plate was modeled by FEM, its load-displacement relationship was obtained and its collapse characteristics were analyzed. The load-displacement relationship indicates its post-ultimate strength behavior, which is shown as that the load carrying capacity has a rapidly reduction when the ultimate strength is exceeded, and that the failure modes of the sandwich plate are determined by the parameter of individual layer. The simulation results were validated against experimental results. Conclusions are drawn: the displacement of sandwich plate under axial compression increased slowly before reaching the ultimate strength, once the ultimate strength was exceeded, the loads exerted on the structures sharply decreased with slowly increased displacement until the plate cracked. The simulation results have a good agreement with the experimental results. The mainly failure modes of sandwich plates can be interpreted as delamination between skin & core and core compression fracture, which are typical failure modes in engineering. The stiffness of sandwich structures decreased due to the interlaminar cracking or skin fracture, further the load carrying capacity decreased, which is of significance for guiding the design of sandwich structures.

A Study of the Various Boundary Conditions for Electrical Analogue Solutions of the Extension and Flexure of Flat Plates

1961 ◽  
Vol 12 (3) ◽  
pp. 275-292 ◽  
Author(s):  
S. C. Redshaw ◽  
K. R. Rushton
Keyword(s):  
Boundary Conditions ◽  
Free Edge ◽  
Experimental Results ◽  
New Method ◽  
Flat Plates ◽  
Electrical Analogue ◽  
Various Boundary Conditions

SummaryThe application of electrical analogue methods to the analysis of the extension and flexure of flat plates is reviewed and the difficulties encountered in the satisfaction of the various boundary conditions are discussed. A new method for treating certain boundary conditions and the operation of the electrical analogue is described. New experimental results for two cases which present great analytical difficulty, the flexure of a plate with a free edge and a plate supported on columns, are given.

Idealized Structural Unit Method for Dynamic Collapse Analysis of Plates

2017 ◽  
Author(s):  
Anna Oksina ◽  
Thomas Lindemann ◽  
Patrick Kaeding
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Structural Unit ◽  
Fatigue Cracks ◽  
Offshore Structures ◽  
Dynamic Loads ◽  
Strength Analysis ◽  
Transient Effects ◽  
Marine Structures ◽  
Collapse Analysis

Marine and offshore structures are subjected to dynamic loads during the lifetime. The values or directions of dynamic loads rapidly change in time, causing a significant rise of inertial forces in structural elements. Dynamic loads appear as result of ship’s movement at sea, wind and wave acting, machinery operation, hull vibration and sometimes even as result of collision or explosion. The corresponding dynamic forces and moments act on the ship hull provoking the appearance of stresses, often leading to buckling, plastic deformations or fatigue cracks of the structural members. To ensure the safety and reliability of structures under dynamic loading it is necessary to estimate the transient effects on the collapse behavior of plate panels. According to the Common Structural Rules (CSR) the safety of marine structures must be proved performing the hull girder ultimate strength check. As a possible tool for the ultimate strength analysis, the Finite Element Method (FEM) is widely spread among engineers. In spite of the great effectiveness, the transient Finite Element Analysis (FEA) remains very time consuming and sometimes difficult to accomplish well. Therefore, the formulation of the Idealized Structural Unit Method (ISUM) is extended for the dynamic collapse analysis of marine structures.

Upon Impact Numerical Modeling of Foam Materials

2017 ◽  
Vol 54 (2) ◽  
pp. 195-202
Author(s):  
Vasile Nastasescu ◽  
Silvia Marzavan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Numerical Analysis ◽  
Numerical Methods ◽  
Boundary Conditions ◽  
General Character ◽  
Foam Material ◽  
Various Boundary Conditions ◽  
Specific Behaviour

The paper presents some theoretical and practical issues, particularly useful to users of numerical methods, especially finite element method for the behaviour modelling of the foam materials. Given the characteristics of specific behaviour of the foam materials, the requirement which has to be taken into consideration is the compression, inclusive impact with bodies more rigid then a foam material, when this is used alone or in combination with other materials in the form of composite laminated with various boundary conditions. The results and conclusions presented in this paper are the results of our investigations in the field and relates to the use of LS-Dyna program, but many observations, findings and conclusions, have a general character, valid for use of any numerical analysis by FEM programs.

scholarly journals Experimental/Numerical Evaluation of Steel Trapezoidal Corrugated Infill Panels with an Opening

2021 ◽  
Vol 11 (7) ◽  
pp. 3275
Author(s):  
Majid Yaseri Gilvaee ◽  
Massood Mofid
Keyword(s):  
Energy Dissipation ◽  
Ultimate Strength ◽  
Steel Plate ◽  
Shear Walls ◽  
Experimental Results ◽  
Structural Performance ◽  
Initial Stiffness ◽  
Infill Panels ◽  
Energy Dissipation Capacity ◽  
Ductility Ratio

This paper investigates the influence of an opening in the infill steel plate on the behavior of steel trapezoidal corrugated infill panels. Two specimens of steel trapezoidal corrugated shear walls were constructed and tested under cyclic loading. One specimen had a single rectangular opening, while the other one had two rectangular openings. In addition, the percentage of opening in both specimens was 18%. The initial stiffness, ultimate strength, ductility ratio and energy dissipation capacity of the two tested specimens are compared to a specimen without opening. The experimental results indicate that the existence of an opening has the greatest effect on the initial stiffness of the corrugated steel infill panels. In addition, the experimental results reveal that the structural performance of the specimen with two openings is improved in some areas compared to the specimen with one opening. To that end, the energy dissipation capacity of the specimen with two openings is obtained larger than the specimen with one opening. Furthermore, a number of numerical analyses were performed. The numerical results show that with increasing the thickness of the infill plate or using stiffeners around the opening, the ultimate strength of a corrugated steel infill panel with an opening can be equal to or even more than the ultimate strength of that panel without an opening.

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