FACTORS CONTROLLING THE STRENGTH OF COMPOSITE BODIES (INTERPHASE FRACTURING OF COMPOSITE BODIES)
Abstract
The factors that control the fracture toughness of adhesive joints at ambient temperature and humidity are the adherend material, its surface finish and geometry, the adhesive composition and curing procedure, the bond thickness, the loading rate and resulting crack velocity and fracture type. Of major concern is the fracture type and the range of crack velocities associated with each type. The major effort during this first quarterly period was directed toward assembling and evaluating high strain rate recording equipment. It is possible by means of an oscilloscope to record load-deflection, deflection-time, load-time and crack length-time simultaneously up to and during crack propagation. The fracture surface can be marked with a ripple pattern of known frequency so that the cracking rate can be measured over microscopic distances. Preliminary test were made on a stoichiometric composition of an epoxy resin and hardener system. The crack extension force for a running crack is 75 % that of a stationary crack, and aluminum bond surface finished of 10 and 25 micro-inch (rms) produce identical toughness.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 17, 1964
- Accession Number
- AD0444163
Entities
People
- E. J. Ripling
- S. Mostovoy
Organizations
- Materials Research Laboratory