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Fully leaky optical-guided mode was employed to determine the difference in the splay and bend flexoelectric coefficient (e1-e3) in negative nematic liquid crystal MS-N01300-000. The experimental curves of reflectivity versus internal angle (angle of incident light to the liquid crystal) were obtained when a laser beam passed through the hybrid-aligned nematic in-plane switching liquid crystal cell; the cell was embedded in pyramid-coupled waveguide with different alternating current (AC) and direct current (DC) voltages. The curves of the applied DC with voltage similar to that of AC shift to the left or the right. Experimental results were then compared with theoretical results derived from elastic continuum theory and multi-layer optical theory of liquid crystals. The approximate value of the flexoelectric coefficient (e1-e3) of MS-N01300-000 is 9.0 x 10-11 C/m. [ABSTRACT FROM AUTHOR]

The effects of double-chamfer triggered pattern to the axial crushing energy absorption behavior of' glass/epoxy circular tubes with the ply pattern of [±0], is reported. Deliberate weakness of 45" chamfered triggers at both ends of the tube is introduced with thc aim of controlling thc crushing performance. Similar to single-chamfer triggered pattern, application of this trigger pattern is an efficient way to weaken the initial peak load P[subcr}, extend the triggering length L[subtr], reduce the probability of catastrophic failure and avoid unstable crushing. The crushing behaviors, the damage characteristics of untriggered, single-chamfer triggered and double-chamfer triggered tubes were studies in detail. Specific crushing stress was used to measure thc energy absorption for tubes of different winding angles. Investigations on the macroscopic collapse mode of the tube, the effects of ply angle, the effect of impact loading and quasi-static loading were performed in the presence of double-chamfer triggers. [ABSTRACT FROM AUTHOR]

Based on the experimental phenomena of flexoelectric response at defect sites in nematic inversion walls conducted by Kumar et al., we gave the theoretical analysis using the Frank elastic theory. When a direct-current electric field normal to the plane of the substrate is applied to the parallel aligned nematic liquid crystal cell with weak anchoring, the rotation of ±1 defects in the narrow inversion walls can be exhibited. The free energy of liquid crystal molecules around the +1 and –1 defect sites in the nematic inversion walls under the electric field was formulated and the electric-field-driven structural changes at the defect site characterized by polar and azimuthal angles of the local director were simulated. The results reveal that the deviation of azimuthal angle induced by flexoelectric effect are consistent with the switching of extinction brushes at the +1 and −1 defects obtained in the experiment conducted by Kumar et al. [ABSTRACT FROM AUTHOR]