Undrained Load Capacity of Torpedo Anchors Embedded in Cohesive Soils

Author(s):  
José Renato M. de Sousa ◽  
Cristiano S. de Aguiar ◽  
Gilberto B. Ellwanger ◽  
Elisabeth C. Porto ◽  
Diego Foppa ◽  
...  

This paper presents a numerical based study on the undrained load capacity of a typical torpedo anchor embedded in a purely cohesive isotropic soil using a three-dimensional nonlinear finite element model. In this model, the soil is simulated with solid elements capable of representing its nonlinear physical behavior and the large deformations involved. The torpedo anchor is also modeled with solid elements, and its geometry is represented in detail. Moreover, the anchor-soil interaction is addressed with contact finite elements that allow relative sliding with friction between the surfaces in contact. A number of analyses are conducted in order to understand the response of this type of anchor when different soil undrained shear strengths, load directions, and number and width of flukes are considered. The results obtained indicate two different failure mechanisms: The first one involves significant plastic deformation before collapse and, consequently, mobilizes a great amount of soil; the second is associated with the development of a limited shear zone near the edge of the anchor and mobilizes a small amount of soil. The total contact area of the anchor seems to be an important parameter in the determination of its load capacity, and, consequently, the increase in the undrained shear strength and the number of flukes and/or their width significantly increases the load capacity of the anchor.

Author(s):  
Cristiano S. de Aguiar ◽  
Jose´ Renato M. de Sousa ◽  
Gilberto Bruno Ellwanger ◽  
Elisabeth de Campos Porto ◽  
Cipriano Jose´ de M. Ju´nior ◽  
...  

This paper presents a numerical based study on the undrained load capacity of a typical torpedo anchor embedded in a purely cohesive isotropic soil using a three-dimensional nonlinear finite element (FE) model. In this model, the soil is simulated with solid elements capable of representing its nonlinear physical behavior as well as the large deformations involved. The torpedo anchor is also modeled with solid elements and its complex geometry is represented. Moreover, the anchor-soil interaction is addressed with contact finite elements that allow relative sliding with friction between the surfaces in contact. Various analyses are conducted in order to understand the response of this type of anchor when different soil undrained shear strengths, load directions as well as number and width of flukes are considered. The obtained results point to two different failure mechanisms: one that mobilizes a great amount of soil and is directly related to its lateral resistance; and a second one that mobilizes a small amount of soil and is related to the vertical resistance of the soil. Besides, the total contact area of the anchor seems to be an important parameter in the determination of its load capacity and, consequently, the increase of the undrained shear strength and the number of flukes and/or their width significantly increases the load capacity of the anchor.


2013 ◽  
Vol 361-363 ◽  
pp. 1765-1771
Author(s):  
Chong Wei Huang ◽  
Shuo Wang ◽  
Xian Zhi Shao ◽  
Xian Zhao Du ◽  
Er Hao Su

Based on the differences between the subgrade of tramcar with monolithic track-bed and the existing subgrade of railway, anew three-dimensional nonlinear finite element model is established in this paper. And then,the numerical analyses are conducted by considering weight load of track structure. The characteristics of mechanical response in the subgrade of tramcar with monolithic track-bed are found by finite analysis, which offers a reference for the future engineering, in terms of the design concept, design basis and theoretical support as well as the basis for decision making.


1987 ◽  
Vol 109 (3) ◽  
pp. 200-209 ◽  
Author(s):  
K. Ueno ◽  
Y. K. Liu

Torsion as a cause of failure in the lumbar intervertebral joint was studied using a three-dimensional nonlinear finite element model. The role of facets and ligaments as well as the stress distributions in the posterior elements, the disk, the ligaments, and the vertebral body were examined. For physiological range of torsion, the facets carried 10 to 40 percent of the torque. The fiber stresses in the disk were the highest at the lateral margin of the outer layer of the annulus. Therefore, torsion itself is unlikely to cause posterior or posterolateral disk prolapse.


1999 ◽  
Vol 121 (4) ◽  
pp. 565-572 ◽  
Author(s):  
R. F. Handschuh ◽  
G. D. Bibel

An aerospace-quality spiral bevel gearset was analytically and experimentally rolled through mesh to investigate tooth bending stress. A nonlinear finite element model utilized multiple teeth from the pinion and gear to simulate three-dimensional multitooth contact. The results were compared to those obtained experimentally with strain gages. A total of five strain gages, mounted in the root/fillet region of three teeth, were used. Effects of changing speed and load were measured. Tests were conducted from static (slow roll) to 14,400 rpm at power levels up to 537 kW (720 hp).


Author(s):  
Sayed A. Nassar ◽  
Zhijun Wu ◽  
Xianjie Yang

A three dimensional nonlinear finite element model is developed for achieving a uniform clamp load in gasketed bolted joints. The model is used for both multiple and single pass tightening patterns. Geometric nonlinearity of the gasket is taken into account and plastic model parameters are experimentally determined. The effect of the tightening pattern, gasket loading and unloading history, and the preload level is investigated. The validity of the FEA methodology is experimentally verified. This study helps improve the reliability of gasketed bolted joints by minimizing the bolt-to-bolt clamp load variation caused by elastic interaction among the various bolts in the joint during initial joint bolt-up.


2003 ◽  
Vol 1823 (1) ◽  
pp. 153-162 ◽  
Author(s):  
Mofreh F. Saleh ◽  
Bruce Steven ◽  
David Alabaster

A three-dimensional nonlinear finite element model (3D-FEM) was developed as part of a study of the effect of increasing axle load and tire pressure on pavement deterioration. The measured strains, interface stresses, and deflections were collected from the instrumented Canterbury Accelerated Pavement Testing Indoor Facility in New Zealand. In addition, two multilayer elastic models were used to compare the values from the finite element simulation and the actual measurements. The first elastic multilayer model was developed with ELSYM5 software, and the second model was developed with CIRCLY software. CIRCLY differs from ELSYM5 in the ability to account for material anisotropy; ELSYM5 considers the pavement materials to be isotropic. The actual strains and deformations were measured by Emu strain gauges embedded at different depths in the base and subgrade materials. Both the unbound granular base and the subgrade materials were modeled in 3D-FEM as elastic plastic materials. The results showed that for the unbound base layer, the strains calculated from the two elastic models were in reasonable agreement with the values measured in the instrumented test track, while the 3D-FEM model tended to overestimate the strains at the bottom of the base. While none of the models provided a perfect fit to the measured strains in the subgrade layer because the subgrade is less homogenous than assumed, 3D-FEM provided the closest fit. Also, CIRCLY provided better results than ELSYM5, which underestimated the displacement values compared with values obtained with CIRCLY and 3D-FEM.


2006 ◽  
Vol 129 (4) ◽  
pp. 575-585 ◽  
Author(s):  
Kathryn B. Higgins ◽  
David R. Sindall ◽  
Alberto M. Cuitino ◽  
Noshir A. Langrana

A three-dimensional nonlinear finite element model (FEM) was developed for a parametric study that examined the effect of synthetic augmentation on nonfractured vertebrae. The objective was to isolate those parameters primarily responsible for the effectiveness of the procedure; bone cement volume and bone density were expected to be highly important. Injection of bone cement was simulated in the FEM of a vertebral body that included a cellular model for the trabecular core. The addition of 10% and 20% cement by volume resulted in an increase in failure load, and the larger volume resulted in an increase in stiffness for the vertebral body. Placement of cement within the vertebral body was not as critical a parameter as cement amount. Simulated models of very poor bone quality saw the best therapeutic benefits.


2014 ◽  
Vol 543-547 ◽  
pp. 617-620
Author(s):  
Xiao Mei Sui ◽  
Zhang Rong Zhao ◽  
Wen Zuo Chen ◽  
Xiao Yu Zhang

This paper presents three dimensional nonlinear finite element modeling of giant magnetostrictive materials. The nonlinear relationship between magnetostrictive strain and magnetic field is described by experimental curve. Model is implemented using finite element software CMOSOL multiphysics 3.2a. A new method for precise machining non-cylinder pin hole of piston by using embedded giant magnetostrictive smart component is presented. The effects on smart component deformation and the system resonance frequencies are studied. This model is verified against experimental results, with a good agreement.


2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Sayed A. Nassar ◽  
Zhijun Wu ◽  
Xianjie Yang

A three-dimensional nonlinear finite element model is developed for achieving a uniform clamp load in gasketed bolted joints. The model is used for both multiple and single pass tightening patterns. Geometric nonlinearity of the gasket is taken into account and plastic model parameters are experimentally determined. The effect of the tightening pattern, gasket loading and unloading history, and the preload level is investigated. The validity of the FEA methodology is experimentally verified. This study helps improve the reliability of gasketed bolted joints by minimizing the bolt-to-bolt clamp load variation caused by elastic interaction among the various bolts in the joint during initial joint-bolt-up.


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