Impact-related damage in glass roving reinforced laminate
Andrzej Bełzowski, Zdzisław Rechul, Jan Stasieńko Politechnika Wrocławska, Wydział Mechaniczny, ul. Smoluchowskiego 25, 50-370 Wrocław
Annals 2 No. 5, 2002 pages 394-398
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abstract Transverse impact loads lower laminate properties and especially its compressive strength as measured parallel to the fibre ply plane. The present paper gives an account of investigations on 4 mm thick glass-epoxy laminate reinforced with woven roving. The compressive strength was found to be reduced by as much as 33% throughout the energy range used (0÷18 J). The material exhibited threshold behaviour with impact energies below 6÷7 J resulting in no strength decrease (Fig. 3). The compressive strength evaluation cannot be decisive, however, since even the low-energy impacts (3÷5 J) gave rise to microstructural damage that, though raising no concern when looked at macroscopically, could accelerate corrosion of the strengthening phase and as such can in no way be neglected (Figs 5-7, 9). The presented study is a clear demonstration that microscope examination is a reliable diagnostic technique that should accompany strength tests since the latter give overly optimistic estimates of the safe impact energy value.