Computation of Pseudo Strain Energy and Paris Law Fracture Coefficients from Surface Energy and Uniaxial Strain-Controlled Tension Test Data
Dissipated pseudo strain energy (DPSE) and Paris' law fracture coefficients constitute input parameters for fracture characterization of hot-mix asphalt concrete (HMAC) mixtures in continuum fracture-damage mechanics and energy based fatigue analysis approaches. In this paper, numerical analysis models for computing DPSE and Paris' law fracture coefficients from surface energy (SE) and uniaxial strain-controlled tension test data are presented. The applicability of the DPSE, Paris' law fracture coefficients, and the associated laboratory tests for comparatively quantifying HMAC mixture fracture properties including investigating the effects of aging is also presented. Analysis of the results indicated that the models utilized together with the computed parameters and the related laboratory tests provide a fundamental methodology of comparatively characterizing the fracture properties of HMAC mixtures. The numerical values obtained were within theoretical expectations. The results further showed that aging...
We give a brief introduction to the study of the algebraic structures -- and their geometrical interpretations -- which arise in the BRST construction of a conformal string background. Starting from the chiral algebra $\cA$ of a string background, we consider a number of elementary but universal operations on the chiral algebra. From these operations we deduce a certain fundamental odd Poisson structure, known as a Gerstenhaber algebra, on the BRST cohomology of $\cA$. For the 2D string background, the correponding G-algebra can be partially described in term of a geometrical G-algebra of the affine plane $\bC^2$. This paper will appear in the proceedings of {\it Strings 95}.