Rong Guo Wang

Numerical Analysis of Delamination Behavior in Laminated Composite with Double Delaminations Embedded in Different Depth Positions

In this article, the finite element method (FEM) using cohesive element is applied to predict the delamination behavior in laminated composite with double delaminations embedded in different depth positions under compressive load. In particular, compared with single delamination composites, the interaction between delaminations and the complicated propagation behavior are discussed. Furthermore, the study is focused on the significant effects of double delaminations on delamination buckling and growth behavior, such as the distance between double delaminations and the delaminations’ depth position.

Damping Analysis of Fibre-Reinforced Composites and Structure

The purpose of the paper is to analyze the damping characteristics of several advanced fibre-reinforced composites, and ulteriorly optimize the damping performance of a composite structure. Numerical modelling of the damping was developed considering the finite element method based on the modal strain energy. The modal damping characteristics of the fibre-reinforced composites were evaluated, including the modal frequencies, modal shapes and modal loss factors. The damping performances of different fibre-reinforced composites were compared. Furthermore, the damping performance of a laminated composite structure was optimized by considering the effects of different lay-up sequences and layer orientations. An optimum design scheme of the composite structure was presented.

Optimum Design of Composite Armor against Transverse Impact

This study presents an effective methodology for the optimum design of two-component armor. The armor consists of two plates: one is boron carbide ceramic and the other is kevlar/epoxy composites. The effect of the thickness of two plates on the ballistic limit velocities of the armor was investigated by Florence model. A finite element model was created using MSC.DYTRAN to simulate the impact of a rigid projectile on the composite armor. The optimum thickness of the ceramic and composite was obtained by evaluating the ballistic resistance efficiency.

Structural Design and Multi-Objective Evaluation of Composite Bladed Propeller

This paper describes the work to design a composite bladed marine propeller. The hydrodynamic load and the nonlinear structural responses are predicted by the coupled FEM/CFD method. A pre-twist strategy is used to determine a new geometry of the composite bladed propeller for improving the hydrodynamic performance. Different material schemes and symmetric stacking sequences are considered as the design parameters. An evaluation method of multi-objective function is presented for optimizing the strength, deflection and mass at design conditions. Numerical results are obtained and the optimal design scheme of the composite bladed propeller is obtained.

Dynamic Responses of Composite Marine Propeller in Spatially Wake

Dynamic responses of a composite marine propeller in spatially wake were investigated in this paper. A hydroelastic model was developed to identify the response characteristics of the composite propeller blades using a finite element method (FEM) coupled with a computational fluid dynamics (CFD) method. Rotational effects and added mass were considered. A coupled matrix was established and solved by the Newton-Raphson numerical procedure. The dynamic characteristics and responses of the composite blade were calculated and compared with those of the counterpart rigid blade. Effects of various parameters, including the layer lamination and fiber orientation were investigated.

Manufacture and Testing of a Moderate Size Integrated Marine Composite Propeller

The composite material has high strength-to-weight, stiffness-to-weight ratios and it has the layer designing property to satisfy special mechanical requirement. Nowadays, the marine produce industry makes efforts to use composites for marine propeller to improve the hydrodynamic and structural performance. In this paper, the authors use FEA coupled CFD to design the layer sequence of composite propeller and develop ANSYS subroutine to simulate resin flow in the mould. The composite propeller is produced by RTM (resin transfer molding) and tested to measure the performance of composite propeller. Compared to the same size aluminum propeller, the composite propeller saves 39% weight and has less noise.

Effect of Thermal-Oxidative Aging on the Mechanical Properties of Carbon Fiber Reinforced Bis-Maleimide Composites

Bis-maleimide (BMI) resins are widely applied in carbon fiber reinforced polymer composites in aerospace fields, for their excellent thermal and mechanical properties. The effects of thermo-oxidative aging on mechanical properties of carbon fiber reinforced BMI composites were investigated by SEM with the combination of flexural strength test and inter-laminar shear strength (ILSS) test. The results indicated that the thermal-oxidative aging had some effects on mechanical properties of carbon fiber/BMI composites; however the testing temperature or service temperature had much more effects than aging time. With aging time increased, the flexural strength at 150 oC and the ILSS at 25 oC slightly increased, while the ILSS at 150 oC decreased gradually. Both test results of mechanical properties and fracture models of damaged flexural specimens by SEM indicated that the matrix resin in the composites showed some viscoelastic behaviors that resulted in the remarkable dependence of mechanical properties of the composites on temperature. Therefore, the carbon fiber reinforced BMI composites had lower flexural strength and ILSS at 150 oC than that at 25 oC.

The Study on Buckling Deformation of Composite Pressure Vessel Based on Acoustic Emission Signals

The buckling deformation of the liner within composite pressure vessel is investigated using acoustic emission (AE) signals. The liner will fail with buckling deformation which is casued by compression stress induced by deformation compatibility beween composite layer and the liner. The experimental results show that these high-amplitude signals higher than 80dB are responsible for the buckling deformation of the liner within composite pressure vessel during unloading process.

The Study of Thermal Boundary Condition for CFRP Pressure Vessel with Metallic Liner during Manufacture Process

The heat convection was considered the main heat exchange type in the autoclave where CFRP pressure vessel was cured in this analysis. To determine the heat convection coefficient, it needed the combination of theoretical calculation and temperature test. In the theoretical calculation, the determination of the heat convection coefficient was considered as an inversion problem of thermal conduction. By adjusting convection coefficient value in the finite element calculation, optimization method was employed to obtain a good agreement between calculated temperature and measured temperature. In the temperature test, the metallic liner of CFRP pressure vessel was used as test component to record temperature data which was compared with the calculated temperature. The calculated results reveal that the maximum value in convection coefficient sequence is 19.87 W/m2/K; the minimum value is 0.16 W/m2/K; the maximum temperature deviation between calculation and test is 1.67 °C. The results present the equivalent thermal boundary condition for the simulation of curing process of CFRP pressure vessel.