Delamination growth for composite laminated cylindrical shells under external pressure

The delamination growth may occur in delaminated cylindrical shells＇under external pressure. This will lead to failure of structure. By using the variational principle of moving boundary and considering the contact effect between delamination regions, in this work, the delamination growth was investigated for cylindrical shells under the action of external pressure. At the same time, according to the Griffith criterion, the formulas of energy release rate along the delamination front were obtained. In the numerical calculation, the delamination growth of axisymmetrical laminated cylindrical shells was analyzed, and the effects of delamination sizes and depths, the geometrical parameters, the material properties, and the laminate stacking sequences on delamination growth were discussed.

BUCKLING AND POSTBUCKLING OF LAMINATED THIN CYLINDRICAL SHELLS UNDER HYGROTHERMAL ENVIRONMENTS

The influence of hygrothermal effects on the buckling and postbuckling of composite laminated cylindrical shells subjected to axial compression is investigated using a micro-to-macro-mechanical analytical model. The material properties of the composite are affected hy the variation of temperature and moisture, and are hosed on a micromechanical model of a laminate. The governing equations are based on the classical laminated shell theory, and including hygrothermal effects. The nonlinear prebuckling deformations and initial geometric imperfections of the shell were both taken into account. A boundary layer theory of shell buckling was extended to the case of laminated cylindrical shells under hygrothermal environments, and a singular peturbation technique was employed to determine buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of perfect and imperfect, cross-ply laminated cylindrical shells under different sets of environmental conditions. The influences played by temperature rise, the degree of moisture concentration, fiber volume fraction, shell geometric parameter, total number of plies, stacking sequences and initial geometric imperfections are studied.

ANALYSIS OF LAMINATED PIEZOELECTRIC CYLINDRICAL SHELLS

A new method is developed for three-dimensional stress analysis of laminated piezoelectric cylindrical shell with simple support. The shell can be subjected to various applied loadings, including distributed body force, inner and outer surface traction and potential. Each layer of the shell can be piezoelectric or elastic/dielectric, with perfect bonding assumed between each interface. The governing equations are solved by the state-space technique. Numerical results are presented to show the sensing and actuating effects of three-layered piezoelectric cylindrical shell.

Transient impact responses of laminated composite cylindrical shells

The generalized ray method(GRM) has been successfully used to study the transient elastic wave transmitting in the beams,planar trusses,space frames and infinite layered media.In this letter,the GRM is extended to investigate the early short time transient responses of laminated composite cylindrical shells under impact load.By using the Laplace transformation and referring to the boundary conditions,the ray groups transmitting in the finite laminated cylindrical shells under the shock load are obtained and the transient response related to each ray group can be derived via FFT algorithm.From the numerical results,it is shown that the early short time transient accelerations of the laminated composite cylindrical shell under impact loads are very large.But the short time transient shear strain and displacement are very small.

EXACT SOLUTION FOR LAMINATED CONTINUOUSOPEN CYLINDRICAL SHELLS

Discarding any assumption about displacement models and stress distribution andintroducing δ-function into the present study, we established the state equation for thecontinuous orthotropic open cylindrical shells. An thentical exocl solution is presentedfor the statics of thin. moderately thick and thick laminated continuous openrylindrical shells. Numerical results are obtained and compared with those calculatedusing SAP5.

Wave transmission through laminated composite double-walled cylindrical shell lined with porous materials

A study on free harmonic wave propagation in a double-walled cylindrical shell, whose walls sandwich a layer of porous materials, is presented within the framework of the classic theory for laminated composite shells. One of the most effective components of the wave propagation through the porous core is estimated with the aid of a flat panel with the same geometrical properties. By considering the effective wave component, the porous layer is modeled as a fluid with equivalent properties. Thus, the model is simplified as a double-walled cylindrical shell trapping the fluid media. Finally, the transmission loss （TL） of the structure is estimated in a broadband frequency, and then the results are compared.

The Exact Solution for Thick Laminated Cantilever Cylindrical Shell

Discarding any ussumption regarding displacement or strers models, the stateequation for orthotropy is established in a cylindrical system. The exact solution ispresented for the statics of thick closed laminated cantilever cylindrical shells. Everyequation of elasticity can be satisfied and all the elastic constants are taken intoaccount. Arbitrary precision of a desired order can be obtained.

STACKING SEQUENCE OPTIMIZA-TION OF LAMINATED COMPOSITE CYLINDER SHELL FOR MAXIMAL BUCKLING LOAD

A new optimization method for the optimization of stacking of composite glass fiber laminates is developed. The fiber orientation and angle of the layers of the cylindrical shells are sought considering the buckling load. The proposed optimization algorithm applies both finite element analysis and the mode-pursuing sampling （MPS）method. The algorithms suggest the optimal stacking sequence for achieving the maximal buckling load. The procedure is implemented by integrating ANSYS and MATLAB. The stacking sequence designing for the symmetric angle-ply three-layered and five-layered composite cylinder shells is presented to illustrate the optimization process, respectively. Compared with the genetic algorithms, the proposed optimization method is much faster and efficient for composite staking sequence plan.

Dynamic Structure-Fluid Interaction Response of a Composite Cylindrical Shell Submerged in Water

This paper analyzes the dynamic structure-fluid interaction response of a submerged composite cylindrical shell. Dynamic equations based on the first-order shear deformation theory include the initial stresses and structure-fluid interaction forces due to fluid. The field equation is solved by expanding the velocity potential into series similar to transverse deflection of the cylindrical shell and the structure-fluid interaction force is obtained. The dynamic response is investigated by means of series expansion method. The effects of structure-fluid interaction on dynamic response are discussed.