Sophia University

About: Sophia University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Nonlinear system & Catalysis. The organization has 4986 authors who have published 7657 publications receiving 106567 citations. The organization is also known as: Jōchi Daigaku.

Damage initiation and growth in composite laminates during open hole compression tests

Abstract: The damage initiation and growth near the edges of a circular open hole of laminated composite plates under compressive load were experimentally studied to understand the physical meaning of the open hole compression strength. Damage growth sequence was investigated mainly through optical micrographs of various sections of damaged specimens. When comparatively tough interface laminates were tested, various damages occurred following initial kink band damage in the 0° layers, such as zigzag damage composed of kink bands and transverse cracks in ±45° layers, matrix cracks in 0° layers, and delaminations above and below the 0° layers. High-speed video images showed that unstable growth of the delaminations near the surface was observed prior to the final failure, accompanying buckling of the delaminated layer. The possible sequences of the damage growth were discussed through consideration of the above damage data.

Compressive behavior of multiply delaminated composite laminates. Part 2 : Finite element analysis

Abstract: Postbuckling behavior of rectangular composite plates with multiple circular delaminations is studied numerically using finite element analysis. Embedded circular delaminations are placed at regular intervals in the thickness direction at the plate center. The plate is fixed along its loading edges and simply supported at its side edges. The three-dimensional block element is adopted to accurately obtain distributions of energy release rates G I , G II , and G III , along the delamination fronts based on the virtual crack closure technique. The contact problem of the delaminated surface is considered through introducing a spring element between nodes at the upper and lower surfaces of the delaminations, which resist only compression force. Buckling loads obtained in the present analysis agree well with those obtained from experiment and classical Rayleigh-Ritz analysis (see companion paper). The complex compressive behavior observed in the experiment can be explained through the results obtained in the present finite element method, which strongly depends on initial imperfections. The distribution of energy release rates in the postbuckling region is also consistent with the failure of the delaminated laminates observed in the experiment

Effects of cueing on visuospatial processing in unilateral spatial neglect.

Abstract: Patients with typical left unilateral spatial neglect bisected lines after cueing to the left end-point, the fixation point being monitored with an eye camera. They persisted with the point of initial fixation made after cueing and placed the mark there without searching leftwards again. The rightward shift of fixation to the initial point of fixation thus determined the location of the subjective midpoint. We consider that rightward attentional bias increased the amplitude of this shift that was planned on the basis of the perception of the whole line while cueing. This hypothesis may explain smaller but obvious rightward bisection errors found in the cueing condition.

Degradation of a REBCO conductor due to an axial tensile stress under edgewise bending: a major stress mode of deterioration in a high field REBCO coil’s performance

Abstract: The influence of an axial tensile stress under edgewise bending on the current transport property of a REBCO-coated conductor is described from the viewpoint of it being one of the major stress modes of degradation in a high field REBCO coil's performance due to electromagnetic forces. A new type of a tensile experiment for the combination of an axial tensile stress, edgewise bending and flatwise bending on a REBCO conductor demonstrates that the combined stress increases tensile strain at the outer edge of the conductor and generates mechanical cracks in the superconducting layer, which causes an earlier degradation than a pure tensile stress. This combined stress mode can cause degradation of a high field REBCO coil's performance below an operating hoop stress and countermeasures need to be developed.