Three-Dimensional Transient Analysis of a Dynamically Loaded Three- Point-Bend Ductile Fracture Specimen
Abstract
A transient three dimensional full field analysis of a three point bend fracture specimen dynamically loaded into the fully yielded plastic state has been carried out. The specimen is rapidly loaded by means of a concentrated transverse force applied at midspan on the uncracked surface of the specimen. The material is ductile and fracture initiation occurs after substantial plastic deformation has developed in the uncracked ligament. Furthermore it is supposed that the crack tip conditions are such that the J integral may be adopted as a characterizing parameter. An expression is derived for the local energy flux appropriate to a three dimensional crack front. Based on this fundamental crack tip flux integral, a domain integral representation for J, suited for the finite element method is obtained. Using the domain integral, accurate pointwise/local values of J along a three dimensional crack front can be extracted from numerically determined field quantities. Transient loading, geometry and plastic deformation on the variation of J along the crack front are examined. The present study determines conditions under which the value of J at initiation may be inferred from quantities that are directly measurable in a dynamic fracture experiment. Earlier a transition time was introduced to provide a practical bound on the time range over which conditions of J dominance prevailed and the deep crack formula was applicable under transient loadings. The transition time concept is further examined. The full field solutions allow comment on the suitability of proposed surface locations for measurement of moment deep crack formula for J, Implications for fracture testing of tough materials at relatively high loading rates are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1986
- Accession Number
- ADA174782
Entities
People
- C. F. Shih
- Lambert Ben Freund
- T. Nakamura
Organizations
- Brown University