Monolithic ceramics have been fabricated from coated green fibers to create fibrous microstructures. The fibrous monoliths consist of high aspect ratio polycrystalline regions (cells) of a primary phase separated by thin secondphase regions (cell boundaries) designed to improve fracture resistance. The cells are the remnants of the green fiber which consists of ceramic powder and a polymer bind...

Mollusk nacre is a prototypical biological inorganic-organic composite that combines high toughness, stiffness, and strength by its brick-and-mortar microstructure, which has inspired several synthetic mimics. Its remarkable fracture toughness relies on inelastic deformations at the process zone at the crack tip that dissolve stress concentrations and stop cracks. The micrometer-scale structure...

Weakly bonded particle mixtures of mullite and alumina are assessed as candidate matrixes for use in porous matrix ceramic composites. Conditions for the deflection of a matrix crack at a fiber-matrix interface are used to identify the combinations of modulus and toughness of the fibers and the matrix for which damage-tolerant behavior is expected to occur in the composite. Accordingly, the pre...

This paper documents the effectiveness of a recycle-in-place (Remixer) process on US175, using results from GPR, FWD, PSPA, condition surveys (crack mapping) and laboratory testing. FWD and PSPA results indicate that the remixed sections are stiff, and the deflection values are in the range typically observed in the Interstate Highway system. This recycling process removes 38mm of AC and adds 2...

Quasi-static and dynamic compression and three-point bending tests have been carried out on Strombus gigas (conch) shells. The mechanical response is correlated with its microstructure and damage mechanisms. The mechanical response is found to vary significantly from specimen to specimen and requires the application of Weibull statistics in order to be quantitatively evaluated. The conch exhibi...

This paper investigates the distribution of principal strain by micro mechanical measurement of concrete axial strain in Reinforced Cement Concrete (RCC) moderate deep beams across its width and depths for various span-to-depth ratios. A complete shear deformational behavior along with load-deflection response, crack patterns and modes of failure were studied experimentally. Twelve beams were t...

Beams, made in brittle materials like concrete or cement, show increasing crack development during their service life due to mechanical and environmental loadings. This local damage can often be translated into reduction of the local bending stiffness values. This paper presents a scanning method to identify the local stiffness values of thin beams using experimentally measured resonance freque...

In this paper, a series of studies to reinforced concrete cracks have been done by image graying, calibrating, image denoising, image enhancement and image segmentation, and the binary image of cracks is finally obtained. Using the Box Method, the fractal dimension of cracks is determined. The relationships between the fractal dimension of surface cracks in the cracking beam under three-point l...

this article studied static deflection, natural frequency and nonlinear vibration of a clamped-clamped microbeam under discontinues electrostatic actuation. the electrostatic actuation was induced by applying ac-dc voltage between the microbeam and electrode plate. in contrast to previous works, it was assumed that length of the electrode plate was smaller than that of the microbeam. in additio...