A mechanical model to determine upheaval buckling of buried submarine pipelines

Thermal loads in submarine pipelines generate an axial compressive load that can force the pipeline to buckle, leading to failure if these loads are not considered in the design. Buried pipes are constraint to displacements in all directions, which leads to a high compressive load in the longitudinal axis and makes the pipes more vulnerable to buckling. If buried pipes under thermal loads do not buckle, a high-stresses state takes place when it is combined with high-pressure conditions. In this work, a simple mechanical model to determine the axial buckling load of a buried pipeline is proposed. The model is based on a simply supported beam subjected to a distributed transverse load representing the soil uplift resistance obtained from a referenced model, and an axial compressive load that represents the effective axial force and is computed according to the DNV-RP-F110. Additionally, the pipe–soil system is analyzed through a non-linear finite element model to compare the results with the analytical solution. The proposed simple mechanical model can capture the upheaval buckling behavior and provides results that are consistent with the numerical analysis, specifically for the two main parameters evaluated, namely, the initial pipe curvature and the magnitude of the transverse load.

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Experimental and Numerical Analyses on the Buckling Characteristics of Woven Flax/Epoxy Laminated Composite Plate under Axial Compression

Polymers ◽

10.3390/polym13070995 ◽

2021 ◽

Vol 13 (7) ◽

pp. 995

Author(s):

Venkatachalam Gopalan ◽

Vimalanand Suthenthiraveerappa ◽

Jefferson Stanley David ◽

Jeyanthi Subramanian ◽

A. Raja Annamalai ◽

...

Keyword(s):

Environmental Sustainability ◽

Composite Plate ◽

Compressive Load ◽

Laminated Composite ◽

Green Composite ◽

Laminated Composite Plate ◽

Axial Compressive Load ◽

Number Of Layers ◽

Structural Applications ◽

Ply Orientation

The evolution of a sustainable green composite in various loadbearing structural applications tends to reduce pollution, which in turn enhances environmental sustainability. This work is an attempt to promote a sustainable green composite in buckling loadbearing structural applications. In order to use the green composite in various structural applications, the knowledge on its structural stability is a must. As the structural instability leads to the buckling of the composite structure when it is under an axial compressive load, the work on its buckling characteristics is important. In this work, the buckling characteristics of a woven flax/bio epoxy (WFBE) laminated composite plate are investigated experimentally and numerically when subjected to an axial compressive load. In order to accomplish the optimization study on the buckling characteristics of the composite plate among various structural criterions such as number of layers, the width of the plate and the ply orientation, the optimization tool “response surface methodology” (RSM) is used in this work. The validation of the developed finite element model in Analysis System (ANSYS) version 16 is carried out by comparing the critical buckling loads obtained from the experimental test and numerical simulation for three out of twenty samples. A comparison is then made between the numerical results obtained through ANSYS16 and the results generated using the regression equation. It is concluded that the buckling strength of the composite escalates with the number of layers, the change in width and the ply orientation. It is also noted that the weaving model of the fabric powers the buckling behavior of the composite. This work explores the feasibility of the use of the developed green composite in various buckling loadbearing structural applications. Due to the compromised buckling characteristics of the green composite with the synthetic composite, it has the capability of replacing many synthetic composites, which in turn enhances the sustainability of the environment.

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Axial Crushing of Multicorner Sheet Metal Columns

Journal of Applied Mechanics ◽

10.1115/1.3176030 ◽

1989 ◽

Vol 56 (1) ◽

pp. 113-120 ◽

Cited By ~ 319

Author(s):

W. Abramowicz ◽

T. Wierzbicki

Keyword(s):

Sheet Metal ◽

Compressive Load ◽

Structural Plasticity ◽

Finite Deformations ◽

Kinematic Parameters ◽

Arbitrary Angle ◽

Axial Compressive Load ◽

Crushing Force ◽

Thin Walled ◽

Theory And Experiments

A method is developed for predicting crush behavior of multicorner prismatic columns subjected to an axial compressive load. The corner element of an arbitrary angle is analyzed first using rigorous methods of structural plasticity with finite deformations and rotations. On that basis, crush predictions are made for multicorner columns with an even number of corners. Static crush tests on square, hexagonal, and rhomboidal thin-walled columns are also reported here. Good correlation between the theory and experiments was obtained for the magnitude of a mean crushing force and kinematic parameters describing the process of progressive folding.

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Basic Experimental Studies of the Local Buckling Strength of Carbon Steel Square Pipes with Circular Hole Subjected to Eccentric Axial Compressive Load. 1st Report. In the Case of Equal Eccentric at the Upper and Lower Ends.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A ◽

10.1299/kikaia.59.1126 ◽

1993 ◽

Vol 59 (560) ◽

pp. 1126-1131

Author(s):

Toshiyuki Kitazawa

Keyword(s):

Carbon Steel ◽

Circular Hole ◽

Experimental Studies ◽

Local Buckling ◽

Compressive Load ◽

Buckling Strength ◽

Axial Compressive Load

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Experimental Characterization and Finite Element Modeling of Film Capacitors for Automotive Applications

Volume 2: Advanced Manufacturing ◽

10.1115/imece2016-65489 ◽

2016 ◽

Author(s):

D. Croccolo ◽

T. M. Brugo ◽

M. De Agostinis ◽

S. Fini ◽

G. Olmi

Keyword(s):

Finite Element ◽

Mechanical Response ◽

High Reliability ◽

Three Dimensional ◽

Strain Analysis ◽

Life Time ◽

Element Model ◽

Image Correlation ◽

Thermal Loads ◽

Mechanical Shock

As electronics keeps on its trend towards miniaturization, increased functionality and connectivity, the need for improved reliability capacitors is growing rapidly in several industrial compartments, such as automotive, medical, aerospace and military. Particularly, recent developments of the automotive compartment, mostly due to changes in standards and regulations, are challenging the capabilities of capacitors in general, and especially film capacitors. Among the required features for a modern capacitor are the following: (i) high reliability under mechanical shock, (ii) wide working temperature range, (iii) high insulation resistance, (iv) small dimensions, (v) long expected life time and (vi) high peak withstanding voltage. This work aims at analyzing the key features that characterize the mechanical response of the capacitor towards temperature changes. Firstly, all the key components of the capacitor have been characterized, in terms of strength and stiffness, as a function of temperature. These objectives have been accomplished by means of several strain analysis methods, such as strain gauges, digital image correlation (DIC) or dynamic mechanical analysis (DMA). All the materials used to manufacture the capacitor, have been characterized, at least, with respect to their Young’s modulus and Poisson’s ratio. Then, a three-dimensional finite element model of the whole capacitor has been set up using the ANSYS code. Based on all the previously collected rehological data, the numerical model allowed to simulate the response in terms of stress and strain of each of the capacitor components when a steady state thermal load is applied. Due to noticeable differences between the thermal expansion coefficients of the capacitor components, stresses and strains build up, especially at the interface between different components, when thermal loads are applied to the assembly. Therefore, the final aim of these numerical analyses is to allow the design engineer to define structural optimization strategies, aimed at reducing the mechanical stresses on the capacitor components when thermal loads are applied.

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