Accession Number : ADP006010

Title :   Stiffness and Residual Strength Variations on Mechanical Joints in CFRP Specimens in Cycling Loading,

Corporate Author : POLITECNICO DI MILANO (ITALY)

Personal Author(s) : Caprile, C. ; Sala, G.

Report Date : MAR 1988

Pagination or Media Count : 24

Abstract : An experimental study of the fatigue behaviour of jointed specimens made of carbon fibre reinforced plastic has been carried out. Four different configurations and four laminations have been taken into account, to point out the influence of by-pass load/transfer load ratio and stacking sequence on specimen fatigue behaviour. Loading frequence has been maintained at 20 C.P.S. in tension-tension tests at room temperature with dry test conditions. Fatigue loads have consisted in an alternate component (20% of failure load) superimposed on a constant tensile force (60% of failure load). The influence of different sequences of constant amplitude load blocks have been also investigated. Residual strength and stiffness versus number of load cycles have been compared for the same stacking sequence by varying specimen configuration, and for different stacking sequences and equal configuration. Elastic and tensile characteristics have been monitored on-line by means of load-cells, LVDT transducers and strain gauges. Damage growth has been inspected by making use of N.D.T. like X-rays radiography with opaque enhanced penetrant liquids and electronic microscope photography. The final results have consisted in a correlation between damage growth and residual strength and stiffness of jointed specimens. (SDW)

Descriptors :   *JOINTS, *RESIDUALS, *STRENGTH(MECHANICS), BEHAVIOR, CARBON FIBERS, CONFIGURATIONS, CYCLES, DAMAGE, ELASTIC PROPERTIES, ELECTRONICS, FATIGUE, FATIGUE(MECHANICS), GROWTH(GENERAL), LAMINATES, LIQUIDS, LOADS(FORCES), MECHANICAL COMPONENTS, MICROSCOPES, ONLINE SYSTEMS, PENETRATION, PHOTOGRAPHY, RADIOGRAPHY, REINFORCED PLASTICS, ROOM TEMPERATURE, SEQUENCES, STACKING, STIFFNESS, STRAIN GAGES, TENSILE PROPERTIES, TENSION, TEST AND EVALUATION, TRANSDUCERS, VARIATIONS, X RAYS.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE