ENGINEERING TRANSACTIONS
ROZPRAWY IN¯YNIERSKIE
A QUARTERLY JOURNAL
- T. Hiroe, K. Fujiwara, H. Hata, K. Natasato, K. Mizokami:
Damage reduction of explosively driven spallation by machining V-notch rows on the surfaces of 304 stainless steel plates
- M. Kawai, M. Futakawa, T. Naoe, H. Yamada, C.N. Xu:
Measurements of strain-rate distributions on material after SHPB impact
- M. Nishida, H. Ichihara, N. Fukuda:
Evaluation of dynamic compressive properties of PLA/PBAT polymer alloys using split Hopkinson pressure bar method
- J. Rychlewski:
Elastic energy decomposition and limit criteria
- T. Hiroe, K. Fujiwara, H. Hata, K. Natasato, K. Mizokami:
Damage reduction of explosively driven spallation by machining V-notch rows on the surfaces of 304 stainless steel plates
- Plane detonation waves generated in the explosive PETN with use of wire-row explosion
technique for initiation have been applied to study on spall behaviour for circular plates of 304
stainless steel, and the slanting surface effects on the damage phenomena for conic frustums
and circular cones. In this paper, V-notch rows are produced on the free surface of the square
plate specimens of the same material and plane shock waves are similarly transferred from the
other surface. The cross-sectional observation of tested and recovered specimens shows that
remarkable effects on the reduction of spall damages have been achieved in case of appropriate
V-notch configurations. The effect seems to come obviously from weakened interaction of release
waves due to the dispersion of directions for reflection waves, and a hydro-code. Autodyn
2D/3D has successfully reproduced the experimental results numerically, suggesting a notch
parameter chart for spall damage evaluation.
Contents
- M. Kawai, M. Futakawa, T. Naoe, H. Yamada, C.N. Xu:
Measurements of strain-rate distributions on material after SHPB impact
- We have proposed a sophisticated novel method of the SHPB experiment to measure
the local strain-rate distributions on a surface of the specimen by using mechanoluminescent
materials combined with a high-speed camera and an image intensifier. The feasibility study
was made for the aluminum specimens pasted by a typical mechanoluminescent material -Eu
doped SrAl2O4 film, in order to obtain the fundamental data for the method. Our results
showed that SrAl2O4: Eu emitted lights as a response to the stress. Increase of the light
intensity was swift enough to follow the strain change due to SHPB impact. The luminescence
intensity was experimentally verified and expressed as a product of strain and strain rate.
Accordingly, it can be said that this method gives a good tool for measuring time variation of
local strain distributions.
Contents
- M. Nishida, H. Ichihara, N. Fukuda:
Evaluation of dynamic compressive properties of PLA/PBAT polymer alloys using split Hopkinson pressure bar method
- Poly(lactic acid) (PLA) is a biodegradable biomass polymer. Polymer blends or polymer alloys
have been used to overcome its brittleness. Because poly(butylene/adipate/terephthalate)
(PBAT) is a ductile and biodegradable polymer, PLA/PBAT polymer alloys can potentially
exhibit high impact strengths. Different mixing ratios of PLA/PBAT (80:20, 70:30 and 60:40)
and the addition of dialkylperoxide as compatibilizing agent for each mixing ratio have been
examined. The stress-strain curves of the PLA/PBAT specimens (observed using a scanning
electron microscope) were measured using a split Hopkinson pressure bar (Kolsky bar) and
a universal testing machine. The PBAT ratios and addition of dialkylperoxide affected the
stress-strain curves. Yield stress decreased with increasing PBAT ratios. Addition of dialkylperoxide
did not change the yield stress of specimens when PLA:PBAT = 80:20. At high strain
rates, the addition of dialkylperoxide clearly reduced yield stress and Young's modulus when
PLA: PBAT = 70:30 and 60:40.
Contents
- J. Rychlewski:
Elastic energy decomposition and limit criteria
- Translated from the original paper in Russian from Advances in Mechanics, 7, 51-80 (1984) by Andrzej Blinowski, scientific editor Ryszard B. Pêcherski. The notes from the editor are added in brackets [...]
Contents
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