ΓΕΝΙΚΕΥΜΕΝΑ ΚΡΙΤΗΡΙΑ ΑΣΤΟΧΙΑΣ ΑΡΧΙΚΩΣ ΑΝΙΣΟΤΡΟΠΩΝ ΕΛΑΣΤΙΚΩΝ ΜΕΣΩΝ ΜΕ ΙΔΙΑΙΤΕΡΗ ΕΜΦΑΣΗ ΣΤΑ ΣΥΝΘΕΤΑ ΥΛΙΚΑ

THE "ELASTIC STRUCTURE" OF LINEARLY ELASTIC ANISOTROPIC MEDIA WAS STUDIED IN TERMS OF SPECTRAL ANALYSIS THEORY OF 4TH RANK SYMMETRIC TENSORS. BY MEANS OF THE SPECTRAL DECOMPOSITION OF THE TRANSVERSELY ISOTROPIC COMPLIANCE TENSOR, ITS EIGENVALUES AND EIGENTENSORS WERE EXPLICITY DEFINED. IT WAS SHOWN THAT THESE EIGENTENSORS DECOMPOSE THE STRAIN ENERGY DENSITY OF TRANSVERSELY ISOTROPIC MEDIA IN WELL DEFINED PARTS ASSOCIATED WITH EIGENDEFORMATION STATES OF THE MEDIUM, AND AN INTERESTING GEOMETRIC INTERPRETATION WAS GIVEN FOR THESE ELASTIC EIGENSTATES.BY GENERALIZING THE CHARACTERIZATION OF ELASTIC SYMMETRY, THE INFLUENCE OF ORTHOTROPIC COMPLIANCE TENSOR COMPONENTS ON THE INCLUDED STRESS FIELD OF PLANE STRESS PROBLEMS WAS STUDIED. BY CALCULATING THE STRESS FIELD IN THE VICINITY OF ANELLIPTIC CUT OF AN ORTHOTROPIC PLATE, AS WELL AS THE STRESS CONCENTRATION INDUCED ON ITS BOUNDARY, IT WAS PROVED THAT FOR A SPECIFIC COUPLING OF THE COMPLIANCE TENSOR COMPONENTS, THE STRESS CONCENTRATION FACTOR TAKES MINIMUM VALUES. THUS, IT IS PROVED THAT IT IS POSSIBLE TO QUANTITATIVELY CORRELATE FRACTURE TOUGHNESS CHARACTERIZATION OF AN ANISOTROPIC LINEAR ELASTIC MEDIUM WITH THE VALUE OF ITS COMPLIANCE TENSOR COMPONENTS. IN THE SEQUEL, THE ISOTROPIC CRITERION OF THEPARABOLOIDAL FAILURE SURFACE OF REVOLUTION WAS GENERALIZED IN ORDER TO PREDICTFAILURE OF ANISOTROPIC MEDIA, AND EXTREMUM PROPERTIES OF THE FAILURE FUNCTION WERE STUDIED IN A GENERALIZED TENSOR INVARIANT FORM. VARIOUS FEATURES OF THE FAILURE CRITERION WERE STUDIED IN DETAIL AND COMPARISON OF ITS THEORETICAL PREDICTIONS WITH EXPERIMENTAL DATA, ESPECIALLY FROM FAILURE TESTS OF FIBER COMPOSITES, PROVED ITS CORRECTNESS. FINALLY, THE GENERALIZATION OF THE ELLIPTIC PARABOLOID FAILURE CRITERION FOR THE GENERALLY ANISOTROPIC ELASTIC SOLID WAS ATTEMPTED FOR THE CASE THAT HYDROSTATIC COMPRESSION IS NOT A SAFE LOADING ANYMORE, BUT SAFE LOADINGS ARE DEFINED IN A SPECIFIC WAY AS A FUNCTION OF THE ELASTIC PROPERTIES OF THE MEDIUM. THUS, ELASTIC STIFFNESS TENSOR AND 4TH RANK FAILURE TENSOR AREPROPERLY INTERRELATED.

Grantor dc:publisher

National Technical University of Athens (NTUA)

Year dc:date

1989

Author dc:creator

• Φιλιππίδης, Θεόδωρος

• Anisotropic elasticiry
• Failure criterion
• Failure surface
• FIBER COMPOSITE MATERIAL
• ORTHOTROPIC MEDIUM
• TRANSVERSELY ISOTROPIC MEDIUM
• ΑΝΙΣΟΤΡΟΠΟΣ ΕΛΑΣΤΙΚΟΤΗΣ
• ΕΓΚΑΡΣΙΩΣ ΙΣΟΤΡΟΠΟ ΜΕΣΟΝ
• Επιφάνεια αστοχίας
• Ινώδες σύνθετο υλικό
• ΚΡΙΤΗΡΙΟΝ ΑΣΤΟΧΙΑΣ
• ΟΡΘΟΤΡΟΠΟ ΜΕΣΟΝ
• Επιστήμες Μηχανικού και Τεχνολογία
• Μηχανική Υλικών
• Engineering and Technology
• Materials Engineering

Language dc:language

gre

Identifier

10.12681/eadd/1193

OAI identifier oai:identifier

oai:10442/1193