MODE OF STRETCHING OF MATERIAL OF A CYLINDRICAL TUBE Russian patent published in 2005 - IPC

FIELD: the invention refers to the field of testing constructional materials of action.

SUBSTANCE: the mode is in weighting with rotation of principal axes of strained state representing whirling stretching of material of the tube. It is executed by means of simultaneous application of axis force, inner pressure and a rotational moment. At that to the whirling stretching spiral increasing or/and decreasing character is added. The weighting is executed with the aid of quasi whirling stretching which means that the rotation of principal axes is executed along four phases forming one cycle of weighting: the first phase - proportional weighting, the second - biaxial stretching with twisting in conditions of proportional weighting, the third - tangential stretching, the fourth - biaxial stretching with twisting in the opposite direction. The weighting on each phase of each cycle is accompanied by following full unloading and the increasing or/and decreasing of stretching tension is provided at the expense of changing its step in each following phase. The step of changing tensions is calculated phase-by-phase in equal portions determinate ratio of difference between the end working tension on the last cycle and working tension on the initial phase of the first cycle to number of steps.

EFFECT: expands functional capabilities.

4 dwg