Carbon fiber reinforced plastic (CFRP) composites have been extensively used in fabrication of primary structures for aerospace, automobile and other engineering applications. With continuous and widespread use of these composites in several advanced technology, the frequency of failures is likely to increase. Therefore, to establish the reasons for failures, the fracture modes should be understood thoroughly and unambiguously. In this paper, CFRP composite have been tested in tension, compression and flexural loadings; and microscopic study with the aid of Scanning Electron Microscope (SEM) has been performed on failed (fractured) composite surfaces to identify the principle features of failure. Efforts have been made in correlating the fracture surface characteristics to the failure mode. The micro-mechanics analysis of failure serves as a useful guide in selecting constituent materials and designing composites from the failure behavior point of view. Also, the local failure initiation results obtained here has been reliably extended to global failure prediction.

We present magnetoresistance measurements on a metallic n-type InP sample on both sides of the metal-insulator transition (MIT). On the metallic side of the MIT, we have observed negative magnetoresistance behaviour, and the experimental data are interpreted in terms of the weak localization and the effect of electron-electron interactions. On the insulator side of the MIT, we have observed positive magnetoresistance associated with variable range hopping conduction. In both cases, experimental data are compared with available theoretical models.

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