Method of determining internal stresses in structural members

US4155264A · kind A · utility

Assignee

• Kraftwerk Union Aktiengesellschaft · DE

Inventors

• Norbert Bender · Nuremberg, DE
• Gerhard Hofer · Königsee, DE
• Olaf Lenz · Molfsee, DE
• Erwin Stucker

Key dates

• Filing date: May 16, 1978
• Grant date: May 22, 1979
• Expiry date: May 16, 1998

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L5/0047
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Method for determining internal stresses in structural members in machine or apparatus manufacturing by machining, around a measuring location provided with strain gages, a circular slot into the surface of the structural member that is to be measured, measuring changes in strain of the core of the measuring location left standing, and calculating the internal stresses from the measured strains and a depth-dependent decay function determined on a calibrating material sample, the improvement therein affording the determination of internal stresses in the structural members at depths greater than about 5 mm, includes the steps of mechanically removing the measuring-location core down to a new surface at the base of the circular slot, securing a strain gage to a new measuring location at the new surface, machining another circular slot around the new measuring location, measuring changes in strain of the core of the new measuring location left standing while measuring changes in strain thereof and repeating the foregoing steps for respective slot depths until a given depth at which internal stresses in the structural members are to be determined is reached, a separate depth-dependent …