Computational Implementation of a Thermodynamically Based Work Potential Model For Progressive Microdamage and Transverse Cracking in Fiber-Reinforced Laminates

A continuum-level, dual internal state variable, thermodynamically based, work potential model, Schapery Theory, is used capture the effects of two matrix damage mechanisms in a fiber-reinforced laminated composite: microdamage and transverse cracking. Matrix microdamage accrues primarily in the form of shear microcracks between the fibers of the composite. Whereas, larger transverse matrix cracks typically span the thickness of a lamina and run parallel to the fibers. Schapery Theory uses the energy potential required to advance structural changes, associated with the damage mechanisms, to govern damage growth through a set of internal state variables. These state variables are used to quantify the stiffness degradation resulting from damage growth. The transverse and shear stiffness of the lamina are related to the internal state variables through a set of measurable damage functions. Additionally, the damage variables for a given strain state can be calculated from a set of evolution equations. These evolution equations and damage functions are implemented into the finite element method and used to govern the constitutive response of the material points in the model. Additionally, an axial failure criterion is included in the model. The response of a center-notched, buffer strip-stiffened panel subjected to uniaxial tension is investigated and results are compared to experiment

Image dehazing using two‐dimensional canonical correlation analysis

Image dehazing is an important issue that interests both image processing and computer vision. In this study, image dehazing is modelled as an example‐based learning problem, and a novel dehazing algorithm using two‐dimensional (2D) canonical correlation analysis (CCA) is proposed. By assuming that the hazy‐free image patches are smooth and the pixel intensities in the same patch are approximate to constant, the authors deduce an underlying linear correlation between the observed hazy image patches and corresponding transmission patches. By maximising the correlation between the patch‐pairs of hazy image and corresponding transmission map, 2D CCA is able to learn a subspace to reconstruct the reliable transmission. Thus, given a test hazy image, the transmission map is aggregated by the nearest neighbour patches in the subspace and then globally refined by a local mean adaptive guided filter. The final hazy‐free image is obtained by using the dichromatic atmospheric model. Experimental results demonstrate the efficiency of the proposed method in single image dehazing