Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
MODE-MIXITY AND DYNAMIC FAILURE MODE TRANSITIONS IN POLYCARBONATE
Autore:
RITTEL D; LEVIN R;
Indirizzi:
TECHNION ISRAEL INST TECHNOL,FAC MECH ENGN IL-32000 HAIFA ISRAEL
Titolo Testata:
Mechanics of materials
fascicolo: 3, volume: 30, anno: 1998,
pagine: 197 - 216
SICI:
0167-6636(1998)30:3<197:MADFMT>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOADED PRENOTCHED PLATES; PROPAGATING SHEAR BANDS; CRACK INITIATION; FRACTURE INITIATION; FIELD; PMMA; TIP;
Keywords:
DYNAMIC FRACTURE; FAILURE MODE TRANSITIONS; MODE-MIXITY; POLYMERIC MATERIALS; FINITE ELEMENTS; FRACTOGRAPHY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
31
Recensione:
Indirizzi per estratti:
Citazione:
D. Rittel e R. Levin, "MODE-MIXITY AND DYNAMIC FAILURE MODE TRANSITIONS IN POLYCARBONATE", Mechanics of materials, 30(3), 1998, pp. 197-216

Abstract

The combination and transition of a shear to opening type of failure mechanism has been reported by for dominant mode II loading of notchedor cracked plates (metallic alloys and polycarbonate). The present paper addresses additional aspects of the phenomenon in relation to mode-mixity for actual fatigue cracks in polycarbonate specimens. Two distinct experimental setups are used and systematically compared throughout the work, by means of numerical simulations and scanning electron fractographic analysis. The first setup allows for dominant mode II loading with a minor mode I component (side impact of cracked plates). A preliminary numerical study accounting for contact and friction between the fatigue crack flanks is carried out. This study shows that, due to the fatigue crack, the initial loading mode is close to ''pure modeII'' followed at a later stage by mixed-mode. The experiments show that by varying the impact velocity, adiabatic shear band formation and fracture can be provoked and controlled, as observed in previous work. For these experiments, a threshold value of K-II (4 MPa m(1/2)) is proposed to trigger shear band formation in the adiabatically heated crack-tip material. The second setup allows for dominant mode I loading with a minor mode II component, using compact compression specimens (CCS). Here, mixed-mode is experienced from the onset of the crack-tip loading throughout the experiment. The comparative fractographic analysis shows that identical characteristic failure mechanisms operate irrespective of the specimen geometry (i.e. mode-mix) and crack-tip nature (notch or crack) for a similar range of impact velocities. Specifically, a shear failure mechanism is also observed in those ''mode I'' (CCS) specimens which were impacted at a higher velocity. This comparativestudy therefore extends the phenomenon of failure mode transition to general mixed-mode loading. (C) 1998 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 02:18:47