Collapse of Tubes Under Combined Bending and Axial Compression Loads

Author(s):  
Shan Jin ◽  
Shuai Yuan ◽  
Yong Bai

In practical application, pipelines will inevitably experience bending and compression during manufacture, transportation and offshore installation. The mechanical behavior of tubes under combined axial compression and bending loads is investigated using experiments and finite element method in this paper. Tubes with D/t ratios in the range of 40 and 97 are adopted in the experiments. Then, the ultimate loads and the local buckling modes of tubes are studied. The commercial software ABAQUS is used to build FE models to simulate the load-shortening responses of tubes under combined loads. The results acquired from the ABAQUS simulation are compared with the ones from verification bending experiment, which are in good agreement with each other. The models in this paper are feasible to analyze the mechanical properties of tubes under combined axial compression and bending loads. The related results may be of interest to the manufacture engineers.

2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Melina Guimarães Alves ◽  
Francisco Carlos Rodrigues ◽  
Ricardo Hallal Fakury ◽  
Ana Lydia Reis de Castro e Silva

RESUMO: Este trabalho avaliou o desempenho relativo de perfis de alma senoidal quando comparados aos perfis de alma plana através do estudo numérico da flambagem local em mesas (FLM) de barras submetidas à compressão axial. Para a realização deste estudo foram discretizados dois modelos via Método dos Elementos Finitos (MEF) com o emprego do programa ABAQUS®. A metodologia numérica baseou-se em realizar análise de carga crítica de flambagem local, mantendo-se fixo os valores de largura de mesas, espessura e altura de alma para cada perfil e alterar gradativamente a espessura das mesas, sendo possível atingir vários resultados de tensão crítica para cada esbeltez, definindo-se a curva tensão versus esbeltez da fase elástica. A partir dos resultados numéricos obtidos foi possível realizar a parametrização analítica com as prescrições da norma ABNT NBR 8800:2008 e fazer uma proposição de metodologia de cálculo para os parâmetros de esbeltez das mesas. Posteriormente, realizaram-se comparativos entre o desempenho dos perfis de alma senoidal e o dos perfis de alma plana. Os resultados numéricos mostraram que o desempenho de um perfil de alma senoidal pode ser até 8% mais eficiente que o dos perfis de alma plana, no que tange a possibilidade de colapso do perfil sem a ocorrência de FLM quando submetidos à compressão axial.ABSTRACT: This work evaluated the relative performance of sinusoidal web profiles through the numerical study of flange local buckling (FLB) for simple bars under compressive strength, when compared to flat web profiles. For this study, two models were discretized using the Finite Element Method (FEM) through the ABAQUS® program. The numerical methodology was based on Buckle analysis, maintaining the values of table width, web thickness and web height for each profile and gradually changing the thickness of the flanges, this way was possible to reach several results of critical tension for each slenderness, being defined the curve of the elastic phase. From the numerical results obtained it was possible to perform the analytical parameterization with the norm ABNT NBR8800:2008 and to make a proposition of calculation for the parameters of slenderness that limit each buckling modes of the flanges. Considering these results, comparisons were made between the performance of the sinusoidal web profiles and those from the flat web profiles. The numerical results showed that the performance of a sinusoidal web profile can be up to 8% more efficient than flat soul profiles, regarding the possibility of collapse of the structure without the occurrence of FLB when subjected under compressive strength.


2006 ◽  
Vol 326-328 ◽  
pp. 1773-1776
Author(s):  
Jin Hwe Kweon ◽  
Sang Min Choi ◽  
Hee Jin Son ◽  
Ji Young Choi ◽  
Jin Ho Choi ◽  
...  

Progressive failure analysis based on the complete unloading method was conducted to investigate the crippling failure of carbon/epoxy composite stiffeners under axial compression. A modified arc-length algorithm was incorporated into a nonlinear finite element method to trace the equilibrium path after local buckling. For the validation of the finite element method, several carbon/epoxy Z-section stiffeners were tested in compression. The finite element results on the buckling and crippling stresses showed good agreement with the experimental results.


1992 ◽  
Vol 20 (4) ◽  
pp. 230-253 ◽  
Author(s):  
T. Akasaka ◽  
K. Kabe ◽  
M. Koishi ◽  
M. Kuwashima

Abstract The deformation behavior of a tire in contact with the roadway is complicated, in particular, under the traction and braking conditions. A tread rubber block in contact with the road undergoes compression and shearing forces. These forces may cause the loss of contact at the edges of the block. Theoretical analysis based on the energy method is presented on the contact deformation of a tread rubber block subjected to compressive and shearing forces. Experimental work and numerical calculation by means of the finite element method are conducted to verify the predicted results. Good agreement is obtained among these analytical, numerical, and experimental results.


2011 ◽  
Vol 374-377 ◽  
pp. 2430-2436
Author(s):  
Gang Shi ◽  
Zhao Liu ◽  
Yong Zhang ◽  
Yong Jiu Shi ◽  
Yuan Qing Wang

High strength steel sections have been increasingly used in buildings and bridges, and steel angles have also been widely used in many steel structures, especially in transmission towers and long span trusses. However, high strength steel exhibits mechanical properties that are quite different from ordinary strength steel, and hence, the local buckling behavior of steel equal angle members under axial compression varies with the steel strength. However, there is a lack of research on the relationship of the local buckling behavior of steel equal angle members under axial compression with the steel strength. A finite element model is developed in this paper to analyze the local buckling behavior of steel equal angle members under axial compression, and study its relationship with the steel strength and the width-to-thickness ratio of the angle leg. The finite element analysis (FEA) results are compared with the corresponding design method in the American code AISC 360-05, which provides a reference for the related design.


2013 ◽  
Vol 281 ◽  
pp. 112-115 ◽  
Author(s):  
Dan Jin ◽  
Zhao Hui Li

Wedge-shaped transducers have been widely used in industry as probes for ultrasonic flowmeters or for ultrasonic flaw detectors. But by now, few studies have focused on the influence to the performance of the wedge-shaped transducers brought by their limited size. In this paper, the effect of the shape and size of wedge-shaped substrates on the whole transducer system is discussed and the shape and size of a transducer (0.5MHz) is optimized to eliminate the influence of the boundary effect by using a 2-D Finite Element (FE) model. Lastly, wedge-shaped transducers have been manufactured for experiment which shows a good agreement with the simulation.


2018 ◽  
Vol 934 ◽  
pp. 24-29
Author(s):  
Prapasiri Pongprayoon ◽  
Attaphon Chaimanatsakun

Graphene nanopore has been widely employed in nanofilter or nanopore devices due to its outstanding properties. The understanding of its mechanical properties at nanoscale is crucial for device improvement. In this work, the mechanical properties of graphene nanopore is thus investigated using atomistic finite element method (AFEM). Four graphene models with different pore shapes (circular (CR), horizontal rectangle (RH), and vertical rectangle (RV)) in sub-nm size which could be successfully fabricated experimentally have been studied here. The force normal to a pore surface is applied to mimic the impact force due to a fluid flow. Increasing pore size results in the reduction in its strength. Comparing among different pore shapes with comparable sizes, the order of pore strength is CR>RH>RV>SQ. In addition, we observe that the direction of pore alignment and geometries of pore edge also play a key role in mechanical strength of nanopores.


2017 ◽  
Vol 09 (05) ◽  
pp. 1750076 ◽  
Author(s):  
Şeref Doğuşcan Akbaş

The purpose of this study is to investigate the thermal effects on the free vibration of functionally graded (FG) porous deep beams. Mechanical properties of the FG deep beam are temperature-dependent and vary across the height direction with different porosity models. The governing equations problem is obtained by using the Hamilton’s principle. In the solution of the problem, plane piecewise solid continua model and finite element method are used. The effects of porosity parameters, material distribution, porosity models and temperature rising on the vibration characteristics are presented and discussed with porosity effects for FG deep beams.


2022 ◽  
Vol 12 (2) ◽  
pp. 575
Author(s):  
Guangying Liu ◽  
Ran Guo ◽  
Kuiyu Zhao ◽  
Runjie Wang

The existence of pores is a very common feature of nature and of human life, but the existence of pores will alter the mechanical properties of the material. Therefore, it is very important to study the impact of different influencing factors on the mechanical properties of porous materials and to use the law of change in mechanical properties of porous materials for our daily lives. The SBFEM (scaled boundary finite element method) method is used in this paper to calculate a large number of random models of porous materials derived from Matlab code. Multiple influencing factors can be present in these random models. Based on the Monte Carlo simulation, after a large number of model calculations were carried out, the results of the calculations were analyzed statistically in order to determine the variation law of the mechanical properties of porous materials. Moreover, this paper gives fitting formulas for the mechanical properties of different materials. This is very useful for researchers estimating the mechanical properties of porous materials in advance.


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