COUPON TESTS OF FIBER-REINFORCED PLASTICS AT ELEVATED-TEMPERATURES INOFFSHORE PROCESSING ENVIRONMENTS

A programme of tests has been conducted to characterise the strength r eduction of three GRP composite materials as a function of temperature and testing environment. The GRP materials and testing environments w ere selected to be of maximum relevance to the offshore industry. The materials were E-glass fibre reinforcement in matrices of three resins : two epoxies and phenolic. The testing environments were sea water an d crude oil condensate. The temperature range tested was ambient to 15 0 degrees C. The tests were performed on coupon specimens laminated us ing fibres in the form of woven mat. The fibres were aligned so as to allow testing in both fibre dominated and resin dominated failure mode s. A novel environmental tensile testing facility was developed for th is work, and this is described briefly. Results are presented for the strength of the three materials as a function of temperature in each f ailure mode when tested dry. These are then compared with equivalent r esults for the specimens tested in the liquid environments. This is th e first reported measurement of GRP strength in liquid environments at these very high temperatures. It is demonstrated from the results tha t strength reduction is exhibited predominantly in the matrix dominate d failure mode, though a small but significant strength reduction is a lso seen in the fibre dominated mode. Causes for these strength reduct ions are identified as lowered glass transition temperature and degrad ation of the glass and glass/resin interfaces respectively. The streng th reductions for each combination of material and environment are qua ntified. Finally, appropriate limits to operating temperature are sugg ested for each material when used in an offshore environment.