Magnetic fabrics in characterization of magma emplacement and tectonic evolution of the Moyar Shear Zone,South India

The Moyar Shear Zone （MSZ） of the South Indian granulite terrain hosts a prominent syenite pluton （-560 Ma） and associated NW-SE to NE-SW trending mafic dyke swarm （-65 Ma and 95 Ma）. Preliminary magnetic fabric studies in the mafic dykes, using Anisotropy of Magnetic Susceptibly （AMS） studies at low-field, indicate successive emplacement and variable magma flow direction. Magnetic lineation and foliation in these dykes are identical to the mesoscopic fabrics in MSZ mylonites, indicating shear zone guided emplacement. Spatial distribution of magnetic lineation in the dykes suggests a common conduit from which the source magma has been migrated. The magnetic foliation trajectories have a sigmoidal shape to the north of the pluton and curve into the MSZ suggesting dextral sense of shear. Identical fabric conditions for magnetic fabrics in the syenite pluton and measured field fabrics in mylonite indicate syntectonic emplacement along the Proterozoic crustal scale dextral shear zone with repeated reactivation history.

Draping Behavior of Carbon Non-Crimp Fabrics and Its Effects on Mechanical Performance of the Hemispherical Composites

In order to investigate the draping behavior of non-crimp fabrics（NCFs）, two types of carbon NCFs with tricot-chain stitches or chain stitches were formed on a hemispherical mould via a stretch forming process. The shear angle and forming defects of the fabrics were measured on the hemisphere, under different blank holder forces（BHFs）. The results showed that increasing BHF could enhance the shear angle slightly, reduce the asymmetry for the deformation of the fabrics, and change the main type of the process-induced defects. Besides, compression tests were performed on the corresponding composite components. By analyzing the change of fiber volume fraction and structural parameters of the textile reinforcements, the effects of draping behavior of NCFs on the mechanical performance of the composites were studied. The results reveal that draping process has distinguishable impacts on the mechanical properties of the final components, which is closely related to the stitching pattern of the NCFs.

DEM investigation on the effect of sample preparation on the shear behavior of granular soil

The effect of initial fabric anisotropy produced by sample preparation on the shear behavior of granular soil is investigated by performing discrete element method （DEM） simulations of fourteen biaxial tests in drained conditions. Numerical test specimens are prepared by three means： gravitational deposition, multi-layer compression, and isotropic compression, such that different initial inherent soil fabrics are created. The DEM simulation results show that initial fabric anisotropy exerts a considerable effect on the shear behavior of granular soil, and that the peak stress ratio and peak dilatancy increase with an increase in the fabric index an that is estimated from the contact orientations. The stress-dilatancy relationship is found to be independent of the initial fabric anisotropy. The anisotropy related to the contact orientation and contact normal force accounts for the main contribution to the mobilized friction angle. Also, the occurrence of contractive shear response in an initial shearing stage is accompanied by the most intense particle rearrangement and microstructural reorganization, regardless of the sample preparation method. Furthermore, the uniqueness of the critical state line in e-logp＇ and q-p＇ plots is observed, suggesting that the influence of initial fabric anisotropy is erased at large shear strains.

Analytical Solution for Predicting In-plane Elastic Shear Properties of 2D Orthogonal PWF Composites

This paper proposes a new analytical solution to predict the shear modulus of a two-dimensional（2D） plain weave fabric（PWF） composite accounting for the interaction of orthogonal interlacing strands with coupled shear deformation modes including not only relative bending but also torsion,etc.The two orthogonal yarns in a micromechanical unit cell are idealized as curved beams with a path depicted by using sinusoidal shape functions.The internal forces and macroscopic deformations carried by the yarn families,together with macroscopic shear modulus of PWFs are derived by means of a strain energy approach founded on micromechanics.Three sets of experimental data pertinent to three kinds of 2D orthogonal PWF composites have been implemented to validate the new model.The calculations from the new model are also compared with those by using two models in the earlier literature.It is shown that the experimental results correlate well with predictions from the new model.