NON-LINEAR ANALYSIS OF THREE-PINNED CIRCULAR ARCHES

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Yong-Lin Pi ◽  
Mark Andrew Bradford ◽  
Kai Luo ◽  
Wei Gao
Keyword(s):  
Compressive Force ◽  
Bending Moment ◽  
Elastic Buckling ◽  
Radial Load ◽  
Bending Moments ◽  
Uniform Load ◽  
Axial Compressive Force ◽  
Plane Analysis ◽  
Linear Behavior ◽  
Non Linear

Because a three-pinned circular arch is statically determinate, when it is subjected to a uniform radial load q, linear in-plane analysis has shown that the uniform load will produce quite simple internal actions: a uniform axial compressive force N = qR and zero-bending moment, where R is the radius of the arch. This is consistent with equations in textbooks for structural mechanics. However, the non-linear behavior and buckling of three-pinned arches are very different from their linear counterparts. The uniform radial load can produce significant bending moments in the three-pinned arches, and the value of the uniform axial compressive force in the three-pinned arches is greater than qR. In addition, it is also shown in this paper that the solutions for the in-plane elastic buckling load of three-pinned arches available in the open literature cannot predict their in-plane buckling loads correctly.

Evaluation of Sealing Performance of Pipe Flange Connection Subjected to External Bending Moments

2009 ◽  
Author(s):  
Yoshio Takagi ◽  
Hiroyasu Torii ◽  
Toshiyuki Sawa ◽  
Kensuke Funada
Keyword(s):  
Bending Moment ◽  
Bending Moments ◽  
Stress Strain ◽  
Flange Connection ◽  
Strain Behavior ◽  
Leakage Test ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Non Linear

The sealing performance of pipe flange connection subjected to an external bending moment was evaluated with the FEM and the experiments. The experimental leakage test using water revealed that the bending moment had an important effect on the sealing performance. The FE analyses suggested that the contact gasket stress, which was a function of the bolt preload, determines the leakage. The changes in contact gasket stress at tension side and compression side when the external bending moment applied were not symmetrical. The reduction in the contact gasket stress of tension side was larger than that of compression side due to the non-linear stress-strain behavior of the gasket. In addition, the hub stress of the flange when external bending moment applied, was evaluated from FE result and the discussion for optimizing the flange design subjected to external bending moment was done in this paper.

EFFECTS OF THE INITIAL DEFLECTION SHAPE ON THE MOMENT AMPLIFICATION FACTOR OF BEAM-COLUMNS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Haruna Utsunomiya ◽  
Masayuki Haraguchi ◽  
Masae Kido ◽  
Keigo Tsuda
Keyword(s):  
Amplification Factor ◽  
Slenderness Ratio ◽  
Compressive Force ◽  
Bending Moment ◽  
Load Ratio ◽  
Longitudinal Direction ◽  
Initial Deflection ◽  
Axial Compressive Force ◽  
Beam Columns ◽  
The Moment

In the design of slender steel beam-columns, the moment amplification factor is used to estimate the maximum moment along with the longitudinal direction. While formulas for evaluating the factor have been presented on the basis of elastic or elastic-plastic analysis, the initial deflection of the column is not considered. The effect that the initial deflection on the strength and behavior of the column has been shown only when the initial deflection shape is half sine wave. This paper discusses the effect of the initial deflection shape on the value of the moment amplification factor by performing the analytical work. The analytical model is the hinged-end beam-column subjected to constant axial compressive force and end moments. First of all, the equilibrium differential equation which governs the problem is solved and the formula for calculating the bending moment is presented. In the parametric study, magnitude of initial deflection, initial deflection shape, axial load ratio, slenderness ratio and end moment ratio are selected as the parameters. In this paper, we discuss the effects of the amount of the initial deflection and the initial deflection shape.

scholarly journals Simplified Design Equations for a Class of Rhombic Auxetic Plates

2018 ◽  
Vol 206 ◽  
pp. 01009 ◽  
Author(s):  
Teik-Cheng Lim
Keyword(s):  
Bending Moment ◽  
Empirical Models ◽  
Simplified Model ◽  
Bending Moments ◽  
Uniform Load ◽  
Load Curve ◽  
Simply Supported ◽  
Exact Data ◽  
Second Derivatives ◽  
Auxetic Materials

Equations for solving the deflection and bending moments of rhombic plates by exact method are known to be highly tedious. A set of simplified equations is developed for design purposes of such simply supported plates under uniform load. Curve-fitting from exact data allows the deflection and its second derivatives, evaluated at the plate centre, to be expressed in greatly simplified and yet sufficiently accurate empirical models for thin rhombic plates. Using the simplified model, it is shown that the maximum bending moment can be reduced by using auxetic materials. By including the effects of shear deformation for thick rhombic plates, it is demonstrated that the ratio of shear-to-bending deformation decreases as the rhombic plate approaches a square shape and as the plate’s Poisson’s ratio becomes more negative.

Estimation of hull girder vertical bending moments including non-linear and flexibility effects using closed form expressions

2009 ◽  
Vol 223 (3) ◽  
pp. 377-390 ◽  
Author(s):  
P T Pedersen ◽  
J J Jensen
Keyword(s):  
Closed Form ◽  
Linear Response ◽  
Bending Moment ◽  
Phase Lag ◽  
Bending Moments ◽  
Hull Girder ◽  
Strip Theory ◽  
Non Linear ◽  
Bow Flare ◽  
Wave Induced

A simple but rational procedure for prediction of extreme wave-induced hull girder bending moment in slender mono-hull displacement vessels is presented. The procedure takes into account main ship hull characteristics such as length, breadth, draught, block coefficient, bow flare coefficient, forward speed, and hull flexibility. The wave-induced loads are evaluated for specific operational profiles. Non-linearity in the wave bending moment is modelled using results derived from a second-order strip theory and water entry solutions for wedge-type sections. Hence, bow flare slamming is accounted for through a momentum type of approach. The stochastic properties of this non-linear response are calculated through a monotonic Hermite transformation. In addition, the impulse loading attributable to, for example, bottom slamming or a rapid change in bow flare is included using a modal expansion in the two lowest vertical vibration modes. These whipping vibrations are added to the wave frequency non-linear response, taking into account the rise time of the impulse response as well as the phase lag between the occurrence of the maximum non-linear load and the maximum impulse load. Previous results for the sagging bending moment are validated by comparison with fully non-linear strip theory calculations and supplemented with new closed form results for the hogging bending moment. Focus is on the extreme hull girder hogging bending moment. Owing to the few input parameters, this procedure can be used to estimate the wave-induced bending moments at the conceptual design phase. Another application area is for novel single-hull ship types not presently covered by the rules of the classification societies. As one application example the container ship MSC Napoli is considered. Further validations are needed, however, in order to select proper values of the parameters entering the analytical form of the slamming impulse.

Bending Capacity of Corroded Pipeline Subjected to Internal Pressure and Axial Loadings

2018 ◽  
Author(s):  
Jie Gao ◽  
Zengli Peng ◽  
Xin Li ◽  
Jing Zhou ◽  
Wenxing Zhou
Keyword(s):  
Internal Pressure ◽  
Local Buckling ◽  
Compressive Force ◽  
Bending Moment ◽  
Corrosive Media ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Offshore Pipelines ◽  
Bending Capacity ◽  
The Moment

Offshore pipelines operating in a harsh environment are usually subjected to combinations of bending moment and axial loadings in addition to internal pressure. Due to the corrosive media transported in the pipelines and corrosive substances within seawater and soil outside the pipelines, local corrosion defects will generate on the pipeline’s inner and outer walls, reducing its ultimate bearing capacity. This paper presents a series of full-scale failure tests and nonlinear finite element analysis (FEA) to study the bending capacity and failure mode of corroded pipelines with outside locally-thinned-areas (LTAs) subjected to combinations of internal pressure, axial compressive force and bending moment. The LTAs are loaded in compression to simulate corrosion. Material tests of API 5L X56 seamless pipe steel were conducted and the stress-strain relationship was obtained. FEA results of the moment versus curvature relation, bending capacity and local buckling behavior of each specimen model matched the experimental results very well, validating the accuracy of this simulation. Additional FEA is then performed to investigate the effect of corrosion geometric parameters, such as corrosion depth, corrosion width, and corrosion length, on the ultimate moment. Among them, the width is of the greatest impact, followed by is the depth, the length impact can be ignored.

MOMENT AMPLIFICATION FACTOR OF BEAM-COLUMNS WITH INITIAL DEFLECTION

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Haruna Utsunomiya ◽  
Masayuki Haraguchi ◽  
Masae Kido ◽  
Keigo Tsuda
Keyword(s):  
Amplification Factor ◽  
Slenderness Ratio ◽  
Compressive Force ◽  
Bending Moment ◽  
Load Ratio ◽  
Initial Deflection ◽  
Axial Compressive Force ◽  
Beam Columns ◽  
Moment Ratio ◽  
The Moment

In the design of slender steel beam-columns, the moment amplification factor is used to estimate the maximum bending moment. The formulas for evaluating the factor have been presented on the basis of the elastic or elastic-plastic analysis, however the initial deflection of beam-columns is not considered. This paper discusses the effect of initial deflection on the value of the moment amplification factor by performing the analytical work. The analytical model is a simply supported beam-column subjected to constant axial compressive force and end moments. First of all, the equilibrium differential equation which governs the problem is solved and the formula for calculating the bending moment is obtained. In the parametric study, magnitude of the initial deflection, the axial load ratio, the slenderness ratio and the end moment ratio are selected as the parameters. The effects of magnitude of the initial deflection and the end moment ratio on the moment amplification factor are discussed.

Postbuckling Analysis of Snaked-Lay Pipelines Based on a New Deformation Shape

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Yuxiao Liu ◽  
Xin Li ◽  
Jing Zhou ◽  
Hualing Song
Keyword(s):  
Control Method ◽  
Compressive Force ◽  
Bending Moment ◽  
Element Model ◽  
Design Criterion ◽  
Lateral Buckling ◽  
Axial Compressive Force ◽  
Nonlinear Finite Element Model ◽  
Pipeline Design ◽  
Control Criterion

Lateral buckling must be considered in exposed HP/HT pipeline design. The snaked-lay method is an effective lateral buckling control method, a new deformation shape of snaked-lay pipeline is presented, and a control criterion of offset angle is also presented. When the offset angle is small or offset angle is large while the pipeline length of snaked-lay is too short or long, the maximum moments of postbuckling pipeline are large. For these problems, a new controlling method combined with snaked-lay and sleeper is proposed, which is named the SS method. Using Ansys, a nonlinear finite element model considering the interaction of seabed-sleeper-pipeline is established. The SS method is proved to be feasible to control lateral buckling for submarine pipelines. Based on critical axial compressive force and maximum bending moment, a design criterion of sleeper height is suggested.

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