Abstract: A method of controlling the location at which yielding initiates a load bearing component and the collapse mode that is activated at the site of yielding for a designated type of loading is claimed. The steps include selecting a desired area of deformation and a kinematic mode of collapse; selecting a strength-altering pattern including at least a strengthening or weakening zone to control the location in a component where plastic deformation occurs, such that the pattern causes deformation to proceed into a desired collapse mode or shape with the component is subjected to design loading; and applying the strength-altering pattern to the component by friction stir processing, forming at least a strengthened or weakened zone relative to the base material of the component.

Abstract: A method of controlling the location at which yielding initiates a load bearing component and the collapse mode that is activated at the site of yielding for a designated type of loading is claimed. The steps include selecting a desired area of deformation and a kinematic mode of collapse; selecting a strength-altering pattern including at least a strengthening or weakening zone to control the location in a component where plastic deformation occurs, such that the pattern causes deformation to proceed into a desired collapse mode or shape with the component is subjected to design loading; and applying the strength-altering pattern to the component by friction stir processing, forming at least a strengthened or weakened zone relative to the base material of the component.

Abstract: Apparatus and method for specific gravity measurement of an object having a known geometry and weight is provided which is particularly adaptable for determining the specific gravity of a gemstone. The apparatus includes a fluid circuit and a pump therefor with the fluid circuit having an adjustable fluid flow rate. The fluid circuit also includes a test chamber element for receiving the object and a flow measuring element for determining fluid flow rate. Preferably, the test chamber is vertically oriented and has zones of decreasing fluid velocity from its lower to upper ends for a constant fluid flow rate through the circuit. The method of measurement is made in one of two modes. In one mode, the flow rate is held constant so that the vertical position of the object of unknown specific gravity in the test chamber yields data allowing calculation of its specific gravity.