METHODS FOR EVALUATION OF OPERATIONAL EFFICIENCY OF PROFILED SHEET FROM POLYMER COMPOSITE MATERIALS Russian patent published in 2020 - IPC G01M5/00 G01N3/20 

FIELD: testing technology; production of composite materials.

SUBSTANCE: invention relates to investigation of strength properties of articles based on profiled sheet (PS) for various purposes from polymer composite materials (PCM). Method comprises testing for three-point bending of sheet specimen by load to close to destructive values of load and deflection and comparing said values with corresponding design values. At the first stage of the test, the submarine sample mounted on the support locating blocks of the test rig is loaded with a linearly distributed load of the specified value, transmitted through loading beam and simulating operating load for specified distance between supports, and for specified time check sheet state and its deflection. At that, it is considered that the sample has passed check under condition of absence of visually observed signs of destruction, and its maximum deformation/deflection under action of rated load during 5 minutes is not higher than allowable design values. At the second stage, the sample is further loaded with a linearly distributed load of a given nominal value, transmitted through loading beam and imitating maximum design value, under conditions of PS control and deflection. At the same time it is considered that the sample has passed the test provided that without the visually observed signs of destruction it has sustained maximum load during 60 minutes. At the third stage, loaded shaped sheet is unloaded and residual deflection state is controlled, wherein it is considered that the sample has passed the test provided that its residual deformations/deflection do not exceed allowable design values. Based on the results of tests carried out at three stages, conclusion is made on workability of the profiled sheet and articles based on it under bending in conditions of use for the intended purpose. Summary: sheet specimen is subjected to bending test to load close to destructive values of load and deflection and comparing said values with corresponding design values, however, the sample of the submarine installed on the supporting locating blocks of the test rig is loaded with a linearly distributed load of the press type, which imitates the operational load for a given distance between the supports, until preset deformations are achieved under conditions of monitoring its state. Sample is considered to have passed the test provided that without the visually observed signs of failure it has withheld maximum deformation/deflection during 60 minutes. Based on the results of the test, a conclusion is made on operational performance of the profiled sheet and articles based on it under bending in conditions of use for the intended purpose.

EFFECT: high accuracy and efficiency of determining mechanical characteristics of profiled sheet products from PCM based on a technique which is easy to implement in practice.

2 cl, 16 dwg