Analysis of mechanical stress field and experimental study on marine band brake

Various lineages of amniotes display keratinized skin appendages (feathers, hairs, and scales) that differentiate in the embryo from genetically controlled developmental units whose spatial organization is patterned by reaction-diffusion mechanisms (RDMs). We show that, contrary to skin appendages in other amniotes (as well as body scales in crocodiles), face and jaws scales of crocodiles are random polygonal domains of highly keratinized skin, rather than genetically controlled elements, and emerge from a physical self-organizing stochastic process distinct from RDMs: cracking of the developing skin in a stress field. We suggest that the rapid growth of the crocodile embryonic facial and jaw skeleton, combined with the development of a very keratinized skin, generates the mechanical stress that causes cracking.

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Robot navigation using a pressure generated mechanical stress field: "the biharmonic potential approach"

Proceedings of the 1994 IEEE International Conference on Robotics and Automation ◽

10.1109/robot.1994.351000 ◽

2002 ◽

Cited By ~ 33

Author(s):

A.A. Masoud ◽

S.A. Masoud ◽

M.M. Bayoumi

Keyword(s):

Stress Field ◽

Mechanical Stress ◽

Robot Navigation ◽

Potential Approach

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Numerical and experimental study of mixed-mode cracks in non-uniform stress field

Procedia Engineering ◽

10.1016/j.proeng.2011.04.282 ◽

2011 ◽

Vol 10 ◽

pp. 1691-1696 ◽

Cited By ~ 3

Author(s):

Daniel Camas ◽

Irene Hiraldo ◽

Pablo Lopez-Crespo ◽

Antonio Gonzalez-Herrera

Keyword(s):

Experimental Study ◽

Stress Field ◽

Mixed Mode ◽

Uniform Stress ◽

Uniform Stress Field

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Finite Element Analysis of the Effect of Mechanical Stress Improvement Process on Weld Residual Stress and Flaw Growth in a Thick-Walled Pressurizer Safety Nozzle

Volume 6B: Materials and Fabrication ◽

10.1115/pvp2017-66104 ◽

2017 ◽

Author(s):

Giovanni G. Facco ◽

Patrick A. C. Raynaud ◽

Michael L. Benson

Keyword(s):

Residual Stress ◽

Finite Element Analysis ◽

Finite Element ◽

Stress Field ◽

Mechanical Stress ◽

Residual Stress Field ◽

Element Analysis ◽

Wide Range ◽

Improvement Process ◽

Stress Prediction

The Mechanical Stress Improvement Process (MSIP) is generally accepted as an effective method to modify the residual stress field in a given component to mitigate subcritical crack growth in susceptible components [1] [2] [3]. In order to properly utilize MSIP, residual stress prediction is needed to determine the parameters of the MSIP application and the expected final residual stress field in the component afterwards. This paper presents the results of a 2D axisymmetric finite element study to predict weld residual stresses (WRS), and associated flaw growth scenarios, in a thick-walled pressurizer safety nozzle that underwent mitigation by application of MSIP. The authors have developed a finite-element analysis methodology to examine the effect of MSIP application on WRS and flaw growth for various hypothetical welding histories and boundary conditions in a thick-walled pressurizer safety nozzle. In doing so, a wide range of repair scenarios was considered, with the understanding that some bounding scenarios may be impractical for this geometry.

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