EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF DYNAMIC COMPRESSIVE BEHAVIOR OF INTACT AND DAMAGED CERAMICS

Persistent Link:
http://hdl.handle.net/10150/193906
Title:
EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF DYNAMIC COMPRESSIVE BEHAVIOR OF INTACT AND DAMAGED CERAMICS
Author:
Luo, Huiyang
Issue Date:
2005
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The mechanical responses of the comminuted ceramic under impact is important in understanding penetration resistance of the target, modeling the penetration process, developing ceramic models and designing better armor systems. To determine the dynamic compressive responses of ceramic rubbles, a novel loading/reloading feature in SHPB experiments was developed to produce two consecutive loading pulses in a single dynamic experiment with two strikers and two shapers. The first pulse pulverizes the intact specimen into rubble after characterizing the intact material. After unloading of the first pulse, a second pulse loads the comminuted specimen and gives the dynamic constitutive behavior of the rubble.With this new experimental technique, several series of experiments were conducted on an oxide ceramic -- alumina AD995 and a non-oxide ceramic--hot pressed silicon carbide, SiC-N, with different strain rates, various volume dilatations and damaged levels under 26 MPa, 56 MPa and 104 MPa confinement. The results show that the strength of the damaged ceramic is not very sensitive to strain rates within this research range and the pulse separation once the damage attains a critical level. When slightly damaged far below a critical level, the specimen remains nearly elastic; when transitionally damaged, the specimen strength gradually decrease from the slight damage level to the heavy damage level. Increasing confinement increases the strength of the ceramics. The crack patterns were dominantly axial splitting for the slight damage, axial splitting and fragmentation for the intermediate damage, and fragmentation and comminution for the heavy damage. For SiC-N, the volume dilatation history shows a delayed failure. SEM observations indicated that microstructural failure mechanism is intergranular fracture for alumina and transgranular fracture for SiC-N.Mohr-Coulomb criterion was successfully employed to describe the damaged ceramic and the parameters were determined. JH-1 model was employed to describe the failed SiC-N in the linearly segmentation description of the strength and the parameters were also determined. Through the analysis of JH-1 model for SiC-N, the critical damage level can be taken as D = 1.0. JH-2 model was used to describe analytically the damaged AD995 and the parameters were obtained. The critical damage value is 0.88 for alumina determined directly from JH-2 model. The description of JH-1 model is equivalent to Mohr-Coulomb criterion while it is unsuitable for JH-2 model due to the non-linear description. Based on the analysis of existing models and current experimental data, an empirical constitutive material model was developed for the damaged ceramic, which well described the completely damaged ceramic, but was unable to model the partially damaged ceramic.
Type:
text; Electronic Dissertation
Keywords:
Ceramics; Dynamic Compressive Response; SHPB; Constitutive Behavior; Silicon Carbide; Alumina
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Mechanical Engineering; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Chen, Weinong

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleEXPERIMENTAL AND ANALYTICAL INVESTIGATION OF DYNAMIC COMPRESSIVE BEHAVIOR OF INTACT AND DAMAGED CERAMICSen_US
dc.creatorLuo, Huiyangen_US
dc.contributor.authorLuo, Huiyangen_US
dc.date.issued2005en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe mechanical responses of the comminuted ceramic under impact is important in understanding penetration resistance of the target, modeling the penetration process, developing ceramic models and designing better armor systems. To determine the dynamic compressive responses of ceramic rubbles, a novel loading/reloading feature in SHPB experiments was developed to produce two consecutive loading pulses in a single dynamic experiment with two strikers and two shapers. The first pulse pulverizes the intact specimen into rubble after characterizing the intact material. After unloading of the first pulse, a second pulse loads the comminuted specimen and gives the dynamic constitutive behavior of the rubble.With this new experimental technique, several series of experiments were conducted on an oxide ceramic -- alumina AD995 and a non-oxide ceramic--hot pressed silicon carbide, SiC-N, with different strain rates, various volume dilatations and damaged levels under 26 MPa, 56 MPa and 104 MPa confinement. The results show that the strength of the damaged ceramic is not very sensitive to strain rates within this research range and the pulse separation once the damage attains a critical level. When slightly damaged far below a critical level, the specimen remains nearly elastic; when transitionally damaged, the specimen strength gradually decrease from the slight damage level to the heavy damage level. Increasing confinement increases the strength of the ceramics. The crack patterns were dominantly axial splitting for the slight damage, axial splitting and fragmentation for the intermediate damage, and fragmentation and comminution for the heavy damage. For SiC-N, the volume dilatation history shows a delayed failure. SEM observations indicated that microstructural failure mechanism is intergranular fracture for alumina and transgranular fracture for SiC-N.Mohr-Coulomb criterion was successfully employed to describe the damaged ceramic and the parameters were determined. JH-1 model was employed to describe the failed SiC-N in the linearly segmentation description of the strength and the parameters were also determined. Through the analysis of JH-1 model for SiC-N, the critical damage level can be taken as D = 1.0. JH-2 model was used to describe analytically the damaged AD995 and the parameters were obtained. The critical damage value is 0.88 for alumina determined directly from JH-2 model. The description of JH-1 model is equivalent to Mohr-Coulomb criterion while it is unsuitable for JH-2 model due to the non-linear description. Based on the analysis of existing models and current experimental data, an empirical constitutive material model was developed for the damaged ceramic, which well described the completely damaged ceramic, but was unable to model the partially damaged ceramic.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectCeramicsen_US
dc.subjectDynamic Compressive Responseen_US
dc.subjectSHPBen_US
dc.subjectConstitutive Behavioren_US
dc.subjectSilicon Carbideen_US
dc.subjectAluminaen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMechanical Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairChen, Weinongen_US
dc.contributor.committeememberKundu, Tribikramen_US
dc.contributor.committeememberShkarayev, Sergey V.en_US
dc.contributor.committeememberSeraphin, Supapanen_US
dc.contributor.committeememberLucas, Pierreen_US
dc.identifier.proquest1087en_US
dc.identifier.oclc137353918en_US
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