3-D Stress Analysis of Cross-Ply Laminated Composites

1994 ◽  
Vol 116 (3) ◽  
pp. 240-249 ◽  
Author(s):  
C. C. Chao ◽  
T. P. Tung ◽  
H. H. Li

A consistent higher-order theory is presented for static deformation and stress analysis of cross-ply thick laminates. Emphasis is placed on consistence with the 3-D boundary conditions and interlaminar stress continuity, exterior and interior, respectively, to the simply supported rectangular plate. All edges and lateral surfaces are considered stress-free, while surface traction and applied load equilibrium is maintained in the loading area. Individual layer displacement fields are expressed in terms of in-plane double Fourier series and cubic polynomials in thickness coordinates with continuity of interlaminar displacements and transverse stresses observed. A system of equations is derived with all these necessary conditions satisfied by means of the higher-order terms of the displacement fields in the extended Rayleigh-Ritz procedure. 3-D displacement and stress components, as compared well with exact solution cases available, can be found throughout the plate for 3-D analysis of localized damage. Thickness shrinking is noted with no mid-surface symmetry of stress distribution.

1994 ◽  
Vol 116 (3) ◽  
pp. 371-378 ◽  
Author(s):  
C. C. Chao ◽  
T. P. Tung ◽  
C. C. Sheu ◽  
J. H. Tseng

A consistent higher-order theory is developed for cross-ply laminated thick plates under transverse normal impact via an energy variational approach, in which the 3-D surface/edge boundary conditions and interlaminar displacement/stress continuities are satisfied, in an attempt to find the dynamic deformation and all six stress components throughout the plate during the impact process. The dynamic displacement field is expressed in a mixed form of in-plane double Fourier series and cubic polynomials through thickness as 12 variables for each layer. A system of modified Lagrange’s equations is derived with all surface and interface constraints included. The nonlinear impact modal analysis is performed using the Hertz contact law in a patch loading simulation and Green’s function for small time-steps linearization. The 3-D displacements are found with thickness shrinking and stresses generally unsymmetric with respect to the mid-surface. Tensile cracks are predicted at the unimpacted side.


2019 ◽  
Author(s):  
Hakwan Lau

I introduce an empirically-grounded version of a higher-order theory of conscious perception. Traditionally, theories of consciousness either focus on the global availability of conscious information, or take conscious phenomenology as a brute fact due to some biological or basic representational properties. Here I argue instead that the key to characterizing the consciousness lies in its connections to belief formation and epistemic justification on a subjective level.


Author(s):  
J. Christopher Maloney

Carruthers proposes a subtle dispositionalist rendition of higher order theory regarding phenomenal character. The theory would distinguish unconscious movement management from conscious attitude management as perceptual processes. Each process takes perceptual representations as inputs. A representation subject to attitude management is apt to induce a higher order representation of itself that secures a self-referential aspect of its content supposedly determinative of phenomenal character. Unfortunately, the account requires a problematic cognitive ambiguity while failing to explain why attitude, but not movement, management, determines character. Moreover, normal variation in attitudinal management conflicts with the constancy typical of phenomenal character. And although an agent denied perceptual access to a scene about which she is otherwise well informed would suffer no phenomenal character, dispositionalist theory entails otherwise. Such problems, together with the results of the previous chapters, suggest that, whether cloaked under intentionalism or higher order theory, representationalism mistakes content for character.


Author(s):  
J. Christopher Maloney

Rosenthal's rendition of representationalism denies intentionalism. His higher order theory instead asserts that a perceptual state's phenomenal character is set by that state's being related to, because represented by, another, but higher order, cognitive state. The theory arises from the doubtful supposition of unconscious perception and mistakenly construes intrinsic phenomenal character extrinsically, as one state's serving as the content of another. Yet it remains mysterious how and why a higher order state might be so potent as to determine phenomenal character at all. Better to resist higher order theory’s embrace of dubious unconscious perceptual states and account for states so-called simply in terms of humdrum mnemonic malfeasance. Moreover, since the suspect theory allows higher order misrepresentation, it implies sufferance of impossible phenomenal character. Equally problematic, representationalism pitched at the higher order entails the existence of bogus phenomenal character when upstairs states represent downstairs nonperceptual states.


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