Fatigue failure load indicator

US4145933A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Leland A. Imig · Seward, US
• William T. Davis · Yorktown, US
• David Davis · Darlington, GB

Key dates

• Filing date: Mar 24, 1978
• Grant date: Mar 27, 1979
• Expiry date: Mar 24, 1998

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N3/32
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An indicator for recording the load at which a fatigue specimen breaks during the last cycle of a fatigue test. A load cell is attached to the specimen which is alternately subjected to tension and compression loads. The output of the load cell which is proportional to the load on the specimen is applied to the input of a peak detector. Each time that the specimen is subjected to a compression load, means are provided for appyling a positive voltage to the reset of the peak detector to reset it. Hence, during the last cycle of the tension load the peak detector measures the maximum load on the specimen. Means are also provided for disconnecting the load cell from the peak detector when there is a failure in the specimen.