Accession Number : ADA256782


Title :   Nonlinear Finite Element Analysis of Metals and Metal Matrix Composites: A Local-Global Investigation


Descriptive Note : Technical rept.


Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB


Personal Author(s) : House, M B ; Bhagat, R B


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a256782.pdf


Report Date : Oct 1992


Pagination or Media Count : 105


Abstract : A computational investigation of the fracture mechanics of metals and metal matrix composites has been carried out. The ductile fracture of structural alloys was analyzed through a two dimensional non-linear finite element approach, while the mechanics of load transfer in silicon carbide (SCS-6) fiber reinforced titanium alloy (Ti-15V-3Cr-3Al-3Sn) were studied using a local-global finite element analysis procedure. The computed values of the J-Integral for compact tension specimens of steel and aluminum alloys (0.533 or - a/W or - 0.884) remain path independent up to a certain load which is attributed to crack initiation, and then diverge. There is a unique signature of the strain energy density (dW/dV) ahead of the crack in the O deg direction: the strain energy first decreases, reaches a minimum and then increases with increasing distance from the crack tip. The minimum strain energy shows a unique dependence on the applied load. This leads to the prediction of the fracture loads for the cracked specimens. A novel coordinate system rotation was employed in extracting the boundary conditions from the two-dimensional global model to the three- dimensional local model for the local-global finite element analysis of the unidirectional composite.


Descriptors :   *FINITE ELEMENT ANALYSIS , *INTEGRALS , *METAL MATRIX COMPOSITES , *MECHANICS , *FRACTURE(MECHANICS) , STRESS STRAIN RELATIONS , METALS , DENSITY , LOAD DISTRIBUTION , FIBERS , FIBER REINFORCED COMPOSITES , PATHS , COORDINATES , ALUMINUM , CRACK PROPAGATION , THREE DIMENSIONAL , BOUNDARIES , STEEL , STRENGTH(MECHANICS) , TOUGHNESS , CARBIDES , J INTEGRALS , STRUCTURAL STEEL , UNIDIRECTIONAL , TITANIUM ALLOYS , SILICON CARBIDES , ROTATION , YIELD STRENGTH , TRANSFER , TITANIUM , TENSION , ENERGY , CRACKS , GLOBAL , ALUMINUM ALLOYS , PREDICTIONS , MODELS , TWO DIMENSIONAL


Subject Categories : Laminates and Composite Materials
      Properties of Metals and Alloys
      Theoretical Mathematics


Distribution Statement : APPROVED FOR PUBLIC RELEASE