scholarly journals Accuracy of finite element analyses of CT scans in predictions of vertebral failure patterns under axial compression and anterior flexion

2016 ◽  
Vol 49 (2) ◽  
pp. 267-275 ◽  
Author(s):  
Timothy M. Jackman ◽  
Alex M. DelMonaco ◽  
Elise F. Morgan
2002 ◽  
Vol 02 (01) ◽  
pp. 45-62 ◽  
Author(s):  
M. GILLIE ◽  
J. M. F. G. HOLST ◽  
M. MÜNCH ◽  
J. M. ROTTER

The controlling design condition in thin metal silos is generally buckling under axial compression. This compression is often assumed to be uniform but in many practical cases several failure modes interact as a result of a rather more complex pattern of stresses. Small silos are often supported on several columns with local brackets attached to the sides of the shell. Failure occurs with an interaction between buckling and yielding under a stress regime involving a combination of membrane and bending stresses developed by the applied loads. This paper firstly reviews the literature relevant to bracket supported silos and exposes the limitations in the available design guidance. The results of a series of finite element analyses are then presented to describe the underlying structural behaviour. It is shown that material and geometric non-linearity both play an important role in the behaviour of discretely supported silos. It is also established that the degree of bracket eccentricity is an important factor in determining the mechanism of failure and the associated strength of the silo. Finally, comparison is made between the numerical results and existing design guidelines.


Author(s):  
Nobuhisa Suzuki ◽  
Ryuji Muraoka ◽  
Alan Glover ◽  
Joe Zhou ◽  
Masao Toyoda

Local buckling behavior of API 5L X100 grade linepipes subjected to axial compression and/or bending moment is discussed in this paper based on results obtained by finite element analyses. Yield-to-tensile strength (Y/T) ratio and design factor were taken into account in the finite element analyses in order to discuss their effects on the local buckling behavior. The local bucking behavior of such lower strength linepipes as X60 and X80 grade linepipes is also discussed for comparison. Two-dimensional solid elements and four-node shell elements were used for the finite element modeling of the linepipes subjected to axial compression and bending moment, respectively. The study has improved the understanding of local buckling behavior of the X100 grade linepipes and observed the following trends. When a linepipe is subjected to axial compression, the critical axial stress decreases with increasing design factor and Y/T ratio. However, the nominal critical strain increases with increasing design factor and decreasing Y/T ratio. When a linepipe is subjected to bending moment, the critical bending moment decreases with increasing design factor and Y/T ratio. Similarly, the nominal critical strain increases with increasing design factor. However, the nominal critical strain increases with decreasing Y/T ratio when the design factor is less than and equal to 0.6 and decreases with decreasing Y/T ratio when the design factor is equal to 0.8.


Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.


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.


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