Describe the concepts of stress-relaxation and creep?
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The creep of a material can be divided into three stages. First stage, or primary creep, starts at a rapid rate and slows with time. Second stage (secondary) creep has a relatively uniform rate. Third stage (tertiary) creep has an accelerating creep rate and terminates by failure of material at time for rupture.\n\nTo determine creep properties, a material is subjected to prolonged constant tension or compression loading at constant elevated temperature. Deformation is recorded at specified time intervals and a creep vs. time diagram is plotted. Slope of curve at any point is creep rate. If failure occurs, it terminates the test and the time for rupture is recorded. If specimen does not fracture within the test period, creep recovery may be measured.\n\nTo determine stress-relaxation of a material, the specimen is deformed a given amount and decrease in stress is recorded over prolonged period of exposure at constant elevated temperature. The stress-relaxation rate is the slope of the curve at any point.
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http://en.wikipedia.org/wiki/Strain_%28materials_science%29\nhttp://en.wikipedia.org/wiki/Specific_gravity\nhttp://en.wikipedia.org/wiki/Stress_%28physics%29\nhttp://en.wikipedia.org/wiki/Reynold%27s_number
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melting physical\nrusting chemical\nburning chemical
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Kinetic, potential, nuclear, chemical and electrical.
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Stress pulls apart. Pressure pushes down.
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Friction, Heat generated to name 2 reasons.
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1. Phys.\n2.Phys..\n3.Phys.\n4.Phys.\n5.Phys.\n6.Chem.\n7.Chem.\n\nChem. Ex:Burning, rusting. irreversable\n\nPhys:ripping, tearing, changes of state. reversable
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The engineering graph is plotted using force vs. elongation.  Stress is then calculated using force divided by cross sectional area, which is a constant.  This cannot simulate true stress because it doesn't account for "necking."\n\nNecking occurs when the sample is about to break.  Usually you can see with your own eyes that the sample begins to thin out before it breaks, thus reducing the cross sectional area (which was held constant in engineering graph).  When necking starts to happen, even the force applied may be smaller, the stress does not decrease, since Stress = Force / Area.
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Natural magnetic variations and decay.  It is like waves of variation.
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They are the stresses normal to a rectangular element of the item being analyzed for stress.  A good explanation can be found here.......\n\n\nhttp://acm.uva.es/p/v104/10429.html
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www.seismology.harvard.edu/\n\nConsult the above link, textbooks will be helpful.
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Tension is a force. It is an external stress tending to pull and object apart. If the force of tension is greater than the inward force of the object, then the object will stretch. Many objects, such as ropes and cables, can only be loaded with tension. If these objects are compressed, then they deform.
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The highest "concentration" of stress will occur at "stress risers."  For example if a shaft is divided along its length with two different diameters, each half will flex depending on its diameter but at the transition there may be a sudden change in stress causing the local stress (in psi - pounds per square inch) to rise well above the average stress of either half on a microscopic basis.  This is where cracks may first form under heavyload.  A very sharp "corner" (small radius) at the change in diameter will increase stress concentration while a large rounded corner will lessen stress concentration (and stress!).  A coone-shhaped transition may be even better.  Any reduction in uniformity of the shaft cross-section (perhaps a key slot) will form a stress riser perhaps requiring the entire shaft to be larger and stronger to compensate for the key-way design.  The yoke you mention would constitute a nonuniformity and could create stress risers and stress concentration.  This is a factor to be considered in good design since it can not be eliminated but only recognized and minimized.  Curved parts are often better than parts with sharp corners or tight bends.  That is why service life tests of components and failure analysis leads to improved designs.  A better design may require a different steel alloy or larger radii when machining or grinding parts or even de-rating allowable loads.  Hope that helps a little.
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The most coherent description I could find was at wikipedia under "spin glass". It's about the time-dependent magnetic characteristic of certain materials that can enter a spin glass phase above a critical temperature. Mean field theory (click the link to this on the referenced page) has been used in theorizing on these dynamics.
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Bernoulli Effects\n\nSee how to demonstrate it here --> http://www.physics.umn.edu/outreach/pforce/Bernoulli.html
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Try,\n\nhttp://www.personal.psu.edu/faculty/d/x/dxh40/MBLemma.pdf
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Le Chåtelier's principle - when a system at equilibrium is disturbed by application of a stress, it attains a new equilibrium position that minimized the stress.\n\nif a liquid substance is added, regardless if the substance is acidic or basic, the shift in equilibrium would be to the right\n\nBecause there would be a net movement of molecules from the liquid phase to the vapor phase, the number of liquid molecules has decreased.  The equilibrium has therefore shifted to the right