Finite-Element Modelling of Multi-Planar Offshore Tubular Joints

2004 ◽  
Vol 126 (1) ◽  
pp. 120-128 ◽  
Author(s):  
Marcus M. K. Lee ◽  
Ellen M. Dexter
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
Finite Element Modelling ◽  
International Organization ◽  
Element Modelling ◽  
Calibration And Validation ◽  
Tubular Joints ◽  
Modelling Procedure ◽  
Test Database

This paper describes the calibration and validation of a finite-element modelling procedure that was used to conduct an extensive parametric study on the strength of multi-planar tubular joints. Various factors that influenced results were investigated. The modelling procedure was calibrated using the International Organization for Standards (ISO) design equations and the underlying test database for compression and tension loaded simple T and Y joints, and was further validated with balanced loaded K joints. Overall, the proposed procedure has been shown to be adequate in predicting the strength of the basic joint types, thereby giving confidence in its use for more complex joints.

scholarly journals Serviceability and flexural strength of lightweight floor made of cold formed steel joists.

2021 ◽  
Author(s):  
Quzzafi Rehman
Keyword(s):  
Finite Element ◽  
Flexural Strength ◽  
Ultimate Strength ◽  
Parametric Study ◽  
Finite Element Modelling ◽  
Dynamic Properties ◽  
Element Modelling ◽  
Floor Systems ◽  
Cold Formed Steel ◽  
Experimental Findings

The use of cold-formed steel (CFS) is becoming popular in residential and commercial building as a cost-effective alternative to traditional wood materials. CFS provides high strength-to-weight ratio, resulting in permitting lighter structure and longer spans. If proper design considerations are not made, this longer span and lighter structure can result in vibration serviceability issues that may affect building occupant comfort. The available design methods to calculate the dynamic properties of floor systems (i.e. Canadian Wood Council Method, CWC; Applied Design Council Design Method, ATC; and Eurocode, EC5) are used for the design of light-frame timber-based systems, CFS C-shape joists, and structural steel and concrete floor systems. The applicability of such methods to I-shape CFS joists is as yet unavailable. In addition, the North American Code for Cold-formed Steel structural Members (CSA-S136-07) provides specifications of ultimate and serviceability limit state design of C-shape joists rather than I-shape joists. As such, this research was divided into three parts. Part 1 presented the results of laboratory and field study on the vibration of a recently developed CFS I-shape joist called “iSPAN.” The main objective of the first part was to understand the dynamic characteristics of iSPAN floor system, recommend an adequate model for predicting the dynamic response and modal properties of floor systems, and correlate its results with engineered wood I-joists in order to aid the design process. Part 2 presented comparison between the experimental findings and available code provisions for the design of CFS joists at ultimate and serviceability limit states. The effect of web utility holes was also considered on the dynamic properties, and ultimate strength of iSPAN joists. Part 3 presented a finite-element modeling and its verification with the experimental findings of the tested samples. Also, part 3 extended the finite element modelling to analyse I- and C-shape CFS joists to determine their ultimate strength and serviceability, with and without the presence of utility holes in the webs. Since CSA-S137-07 does not provide design provisions for the edge-stiffened (i.e. lipped) holes, a practical-design-oriented parametric study, using the finite-element modelling, was conducted on CFS I- and C-shape members with circular, slotted and tri-slotted, edge-stiffened, holes under flexural loading. The optimized profile of the edge-stiffened holes was obtained using the elastic-buckling analysis. The post-buckling finite-element analysis was then utilized to determine member flexural strength as affected by utility hole geometry and web depth. Results showed that the edge-stiffened holes can significantly improve the flexural strength of CFS joists. The data generated from the parametric study was used to develop new design provisions to predict the flexural strength of such joists with the presence of edge-stiffened holes.

The Effects of Crack Growth History on Fracture Toughness

2019 ◽  
Author(s):  
M. A. Probert ◽  
H. E. Coules ◽  
C. E. Truman ◽  
M. Hofmann
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Crack Growth ◽  
Parametric Study ◽  
Finite Element Modelling ◽  
Crack Tip ◽  
High Yield ◽  
Element Modelling ◽  
History Effects ◽  
Apparent Fracture Toughness

Abstract The introduction of cracks into loaded versus unloaded components has a significant effect on the apparent fracture toughness within finite element modelling. The history effects of crack introduction can be beneficial to defect assessment procedures that do not consider prior plasticity specifically from crack introduction. It is assumed that as strain energy is released due to plastic deformation during crack formation a reduction in the energy available for crack propagation under fracture conditions is experienced. This can be characterized by the formation of a plastic wake behind the crack tip and leads to significant increases in load at critical J and other crack growth parameters for modelling situations. However experimental evidence validating this apparent fracture toughness increase are needed. A beneficial increase in apparent fracture toughness can prolong the life of components that might be taken out of service prematurely if history effects are not considered. This paper discusses a series of experimental and modelling approaches that have been taken to assess the magnitude of the benefit in increase of apparent fracture toughness by the manipulation of crack introduction history effects. An initial parametric study of material properties on the effect of introducing cracks into loaded and unloaded components indicates that most benefit be derived from high hardness, high yield materials such as Aluminum 7000 series alloys. Further work has been carried out with experimental C(T) specimens of Aluminum Alloy 7475 T7351. Cracks were introduced by fatigue into the samples. One set of specimens was fatigued with a low mean load and the other with a high mean load, this was achieved by keeping a consistent ΔKI between specimens and changing the load ratio one set of specimens. Fracture test results indicate that the influence of prior plasticity on fracture initiation is much subtler in experimental trials than in the finite element model. Crack growth resistance curves and neutron diffraction results measuring the residual stress created ahead of the crack tip by this method are be discussed and contrasted with the parametric study and finite element modelling of the two different crack introduction scenarios.

scholarly journals Analytical and Finite Element Modelling of Circular Glare Plates under Indentation Loading and Unloading

2011 ◽  
Vol 20 (4) ◽  
pp. 096369351102000 ◽  
Author(s):  
George J. Tsamasphyros ◽  
George S. Bikakis
Keyword(s):  
Finite Element ◽  
Finite Element Modelling ◽  
Circular Plates ◽  
Element Modelling ◽  
Modelling Procedure ◽  
Static Indentation ◽  
Analytical Formulas ◽  
Loading And Unloading ◽  
Analytical Expressions ◽  
Dent Depth

In this paper, analytical expressions are derived and a finite element modelling procedure is proposed in order to predict the static load-indentation curves of circular GLARE fibre-metal laminates during loading and unloading by a hemispherical indentor. Analytical formulas have been recently published for the static indentation of circular GLARE plates which are now used during the loading stage. Here, considering that aluminum layers are in a state of membrane yield and employing energy balance during unloading, the unloading path is determined. Using this unloading path, an algebraic equation is derived and solved for calculating the permanent dent depth of the GLARE plate after the indentor's withdrawal. ANSYS software is used and a non-linear analysis is employed with geometric and material non-linearities for FEM calculations. The derived formulas and the proposed finite element modelling procedure are applied to GLARE 2-2/1-0.3 and to GLARE 3-3/2-0.4 circular plates. The analytical results are compared with corresponding FEM results and a good agreement is found. The analytically calculated permanent dent depth is within 6 % for the GLARE 2 plate, and within 7 % for the GLARE 3 plate, of the corresponding numerically calculated result. No other solution of this problem is known to the authors.

scholarly journals Serviceability and flexural strength of lightweight floor made of cold formed steel joists.

2021 ◽  
Author(s):  
Quzzafi Rehman
Keyword(s):  
Finite Element ◽  
Flexural Strength ◽  
Ultimate Strength ◽  
Parametric Study ◽  
Finite Element Modelling ◽  
Dynamic Properties ◽  
Element Modelling ◽  
Floor Systems ◽  
Cold Formed Steel ◽  
Experimental Findings

The use of cold-formed steel (CFS) is becoming popular in residential and commercial building as a cost-effective alternative to traditional wood materials. CFS provides high strength-to-weight ratio, resulting in permitting lighter structure and longer spans. If proper design considerations are not made, this longer span and lighter structure can result in vibration serviceability issues that may affect building occupant comfort. The available design methods to calculate the dynamic properties of floor systems (i.e. Canadian Wood Council Method, CWC; Applied Design Council Design Method, ATC; and Eurocode, EC5) are used for the design of light-frame timber-based systems, CFS C-shape joists, and structural steel and concrete floor systems. The applicability of such methods to I-shape CFS joists is as yet unavailable. In addition, the North American Code for Cold-formed Steel structural Members (CSA-S136-07) provides specifications of ultimate and serviceability limit state design of C-shape joists rather than I-shape joists. As such, this research was divided into three parts. Part 1 presented the results of laboratory and field study on the vibration of a recently developed CFS I-shape joist called “iSPAN.” The main objective of the first part was to understand the dynamic characteristics of iSPAN floor system, recommend an adequate model for predicting the dynamic response and modal properties of floor systems, and correlate its results with engineered wood I-joists in order to aid the design process. Part 2 presented comparison between the experimental findings and available code provisions for the design of CFS joists at ultimate and serviceability limit states. The effect of web utility holes was also considered on the dynamic properties, and ultimate strength of iSPAN joists. Part 3 presented a finite-element modeling and its verification with the experimental findings of the tested samples. Also, part 3 extended the finite element modelling to analyse I- and C-shape CFS joists to determine their ultimate strength and serviceability, with and without the presence of utility holes in the webs. Since CSA-S137-07 does not provide design provisions for the edge-stiffened (i.e. lipped) holes, a practical-design-oriented parametric study, using the finite-element modelling, was conducted on CFS I- and C-shape members with circular, slotted and tri-slotted, edge-stiffened, holes under flexural loading. The optimized profile of the edge-stiffened holes was obtained using the elastic-buckling analysis. The post-buckling finite-element analysis was then utilized to determine member flexural strength as affected by utility hole geometry and web depth. Results showed that the edge-stiffened holes can significantly improve the flexural strength of CFS joists. The data generated from the parametric study was used to develop new design provisions to predict the flexural strength of such joists with the presence of edge-stiffened holes.

Parametric Study of Concentrated Contact of Rigid Indenter with Elastic-Plastic Material

2016 ◽  
Vol 368 ◽  
pp. 29-32
Author(s):  
Dušan Zíta ◽  
Jaroslav Menčík
Keyword(s):  
Finite Element ◽  
Rigid Body ◽  
Rough Surface ◽  
Parametric Study ◽  
Finite Element Modelling ◽  
Plastic Material ◽  
Contact Problems ◽  
Element Modelling ◽  
Elastic Plastic ◽  
Elastic Plastic Material

This paper shows the results of finite element modelling of contact problems between perfectly rigid body with rough surface and an indenter from elastic-plastic material. In the first phase, spherical indenter from elastic – plastic material is considered, which is pressed into a body with a rough surface. Results show the influence of the amplitude and distances of various undulations at the rough surface to response surface.

Impact of Different Boundary Conditions on the Response of Glare Fiber-Metal Laminates under Lateral Indentation

2016 ◽  
Vol 25 (2) ◽  
pp. 096369351602500
Author(s):  
George S.E. Bikakis ◽  
Alexander Savaidis
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Finite Element Modelling ◽  
Strain Energy ◽  
Tensile Fracture ◽  
Element Modelling ◽  
Different Boundary Conditions ◽  
Simply Supported ◽  
Modelling Procedure ◽  
Load Indentation

In this paper, a finite element modelling procedure is implemented in order to predict the static load-indentation curves and the defection shape of simply supported circular GLARE fibre-metal laminates subjected to lateral indentation by a hemispherical indentor. ANSYS software is used and a non-linear analysis is employed with geometric and material non-linearities for FEM calculations. The finite element modelling procedure is applied to GLARE 2–2/1–0.3 and to GLARE 3–3/2–0.4 simply supported circular plates with various diameters. It is found that the simply supported circular GLARE plates deform axisymmetrically from the beginning of the indentation process up to the point of their first failure due to glass-epoxy tensile fracture. By comparison of the obtained load-indentation curves to corresponding previously published load-indentation curves of clamped circular GLARE plates, the effect of the different boundary conditions on their lateral indentation response is studied. Furthermore, the strain energy-indentation curves of the considered circular GLARE 2 and GLARE 3 plates with simply supported and clamped boundaries are calculated and compared. It is found that the simply supported GLARE plates have reduced stiffness and demonstrate an increased first failure defection due to glass-epoxy tensile fracture versus the clamped GLARE plates, whereas the first failure load is not significantly affected by the different boundary conditions. It is also found that for the same lateral indentation, simply supported GLARE plates absorb lower strain energy levels than clamped GLARE plates. Referring to a specific lateral indentation level, the influence of the different boundary support on the corresponding indentation load and the absorbed strain energy is strong and can reach a deviation level of 45 % between the two support types. To our knowledge, a research concerning the response of simply supported GLARE plates under lateral indentation has not been published elsewhere.

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