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A series of polymer concretes using furan resin, silica aggregates, and microfiller were prepared for statistically designed combinations. The combinations were designed based on the mixture-design concept of design of experiments. The fillers chosen for the present investigation were high-purity naturally occurring silica of different particle sizes, their mix proportion optimized to have minimum void. For each polymer concrete combination, the mechanical properties were studied. Each response (mechanical property) was individually optimized for maximum values and compared with the experimental data. To obtain a single-input combination, having maximum values in all the responses, a combined optimization was done and a mix design was recommended. The coefficient of correlation between the experimental values and predicted values was found to be high, proving the fitness of the selected model. The effect of individual variables on the response was discussed.

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Needle insertion, a standard process for various minimally invasive surgeries, results in tissue damage which sometimes leads to catastrophic outcomes. Opaqueness and inhomogeneity of the tissues make it difficult to...

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Separation of skin and stringer is likely to be a failure mode in co-cured composites stiffened panels where there is considerable out-of-plane deformation. Such deformations are possible when a stiffened skin structure is loaded in compression/shear beyond buckling or in structures which contain a disbond/delamination at the skin–stringer interface. Prediction of damage initiation and progressive growth in numerical simulations require parameters such as interface fracture toughness which have to be obtained through specimen tests. Since interface toughness is generally mode dependent, this study deals with the design and testing of three different configuration of blade stiffened co-cured composite skin–stringer specimens under mode-I and mode-II dominated loading. Finite element numerical models are developed using three-dimensional cohesive elements to predict the disbond growth under mode-I and mode-II dominated loading. The work also addresses the complexities in the convergence of numerical simulations that arise due to cohesive elements. A systematic way to obtain the best values for cohesive element parameters while finding a balance between accuracy of the results, computation time and numerical stability is presented. The present cohesive element modelling and analysis methodology successfully predicted the disbond growth in skin–stringer specimen and can be used to predict disbond/delamination onset or growth in composite stiffened structures subjected to high bending.