The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 1989
Filed:
May. 31, 1988
Shigeo Sakurai, Hitachi, JP;
Sadao Umezawa, Mito, JP;
Saburo Usami, Hitachi, JP;
Hiroshi Miyata, Mito, JP;
Hajime Toriya, Hitachi, JP;
Kuniyoshi Tsubouchi, Mito, JP;
Ryoichi Kaneko, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The life expectancy of a mechanical structure that undergoes repeated loading is estimated by determining the maximum crack length on the surface of the structure. The maximum length of the cracks on the surface of the structure is related to the life ratio of the structure, wherein the life ratio is a ratio of the number of loads the structure has undergone to the number of loads the structure will undergo until failure. An optical system is used to measure the crack length of the cracks on the surface of the structure being inspected. A statistical distribution of greatest length cracks for a sampling of areas within a larger area can be made. Apparatus is provided to statistically process such distribution data to obtain a statistically estimated maximum length crack for the larger area. The maximum crack length determination can be used to estimate the life expectancy of the structure from the relationship between crack length and life ratio.