TY - THES

T1 - Improvement of the Impact Properties of Centrifugally Cast Glass Fibre Reinforced Plastics Pipes

AU - Kucher, Georg

N1 - embargoed until null

PY - 2006

Y1 - 2006

N2 - Impacts on GRP-pipes cause cracks in the wall structure in the liner. This thesis focuses on comparing investigations of different liner resin types on their crack resistance with the objective to identify the best material and the most suitable testing method. Furthermore it was intended to learn more about the impact process. Charpy tests with razor notched specimens (in wet condition) showed which materials have the best performance. But fracture mechanics tests of the liner resins showed a quite different ranking. Impact strike tests on laboratory pipes come close to reality and were therefore performed to prove the suitability of the other test methods. Charpy test results with razor notched specimens are similar to the impact strike tests and seem to be a suitable test substitution. Deformation and liner surface strains of a GRP pipe during an impact were measured with a high-speed camera system. DMA exhibited the E-modulus increase of each pipe wall layer. Thus the single layer stresses could approximately be calculated for the moment of maximum strain. The influence of already existing cracks on long term properties was investigated by burst pressure regression tests. It emerged that pipes with impact damages show the same long term behaviour as intact pipes, but on lower service pressure levels depending on the degree of applied impact energy.

AB - Impacts on GRP-pipes cause cracks in the wall structure in the liner. This thesis focuses on comparing investigations of different liner resin types on their crack resistance with the objective to identify the best material and the most suitable testing method. Furthermore it was intended to learn more about the impact process. Charpy tests with razor notched specimens (in wet condition) showed which materials have the best performance. But fracture mechanics tests of the liner resins showed a quite different ranking. Impact strike tests on laboratory pipes come close to reality and were therefore performed to prove the suitability of the other test methods. Charpy test results with razor notched specimens are similar to the impact strike tests and seem to be a suitable test substitution. Deformation and liner surface strains of a GRP pipe during an impact were measured with a high-speed camera system. DMA exhibited the E-modulus increase of each pipe wall layer. Thus the single layer stresses could approximately be calculated for the moment of maximum strain. The influence of already existing cracks on long term properties was investigated by burst pressure regression tests. It emerged that pipes with impact damages show the same long term behaviour as intact pipes, but on lower service pressure levels depending on the degree of applied impact energy.

KW - Impact Schlagbeanspruchung GFK GRP Rohr Liner Innendruck Regression Charpy Bruchmechanik Fallversuch DMA Aramis Linerrisse Mikrorisse

KW - impact GRP CC-GRP pipe regression Charpy fracture mechanics DMA liner cracks microcracks Aramis pressure FEM

M3 - Diploma Thesis

ER -