An integrated modeling of the curing process and transverse tensile damage of unidirectional CFRP composites

The reduction of both energy consumption and production/maintenance costs in the industry requires the use of advanced engineering materials with remarkable features, including lightweight and long-term service life. As one of the advanced engineering materials, composites are widely applied in industry and civilian daily life. Nevertheless, there are some mechanical factors such as tensile strength restricting the application of such a material. To this end, this study is aimed to comprehensively review the recent research on the effects of fabrication characteristics on the tensile resistance of GFRP, CFRP, and AFRP composites. As revealed by recent progress, the epoxy resin is an advisable option for the production of high-performance polymeric composites due to the remarkable tensility, compression, and corrosion resistance. However, the high cost of epoxy resin is not favorable for mass production. In hybrid composites, stacking sequence is a vital factor that determines the ultimate tensile strength. In terms of higher mechanical performance, some researchers suggested using Kevlar fibers with woven orientation alongside the Carbon as axial fibers. At the same time, it is essential to carefully establish the value of fiber volume fraction. Otherwise, this can lead to dramatic internal defects such as agglomeration. In general, this review article was performed to investigate the impacts of composite fabrication characteristics such as fabrication method, reinforcing fibers orientation, fiber type, matrix phase type, and volume fraction of reinforcing phase on the tensile properties of composites used in aerospace, military, civil constructions, and automotive applications. In addition, the authors tried their best to make this research a credible source in the field of mechanical properties of CFRP, GFRP, and AFRP composites for future studies of other researchers. 

A review on fabrication techniques and tensile properties of glass, carbon, and Kevlar fiber reinforced rolymer composites

The effect of residual stress build-up on the transverse properties of thermoset composites is studied through direct and inverse process modeling approaches. Progressive damage analysis is implemented to characterize composite stiffness and strength of cured composites microstructures. A size effect study is proposed to define the appropriate dimensions of Representative Volume Elements (RVEs). A comparison between periodic (PBCs) and flat (FBCs) boundary conditions during curing is performed on converged RVEs to establish computationally efficient methodologies. Transverse properties are analyzed as a function of the fiber packing through the nearest fiber distance statistical descriptor. A reasonable mechanical equivalence is achieved for RVEs consisting of 40 fibers. It has been found that process-induced residual stresses and fiber packing significantly contribute to the scatter in composites transverse strength. Variation of ±5% in average strength and 18% in standard deviation are observed with respect to ideally cured RVEs that neglect residual stresses. It is established that process modeling is needed to optimize the residual stress state and improve composite performance.

https://www.mdpi.com/2073-4360/13/15/2491/pdf

Effect of Manufacturing on the Transverse Response of Polymer Matrix Composites.

An insight into the mechanical behavior of adhesively bonded plain-woven-composite joints using multiscale modeling

To reconcile the contradiction between the improvement of carbon fiber reinforced resin matrix (CFRP) composite performance and the increase of manufacturing cost, this paper proposes a collaborative optimization strategy for the cure process during the composite manufacture to reduce both the process-induced defects and the process time. Considering the multiscale characteristics of the composites, the temperature gradient is calculated by the macroscale laminate model through the nonlinear heat transfer thermochemical analysis, and the residual stresses are obtained by the representative volume element (RVE) microscale model, which involves the viscoelasticity, thermal expansion and cure shrinkage of the constituents during the thermomechanical analysis. The multi-objective optimization is implemented by an interface which combines the finite element based cure process analysis with the non-dominated sorting genetic algorithm-II (NSGA-II). The results show the proposed optimization strategy can significantly reduce the maximum temperature gradient, the maximum residual stress and the process time simultaneously. Besides, the self-organizing map (SOM) obtained from the Pareto front clarifies the relationship between the design variables and the objectives. 

Multiscale collaborative optimization for the thermochemical and thermomechanical cure process during composite manufacture

Microscale viscoplastic analysis of unidirectional CFRP composites under the influence of curing process

This paper develops a multi-objective optimization method for the cure of thick composite laminates. The purpose is to minimize the cure time and maximum temperature overshoot in the cure process by designing the cure temperature profile. This method combines the finite element–based thermo-chemical coupled cure simulation with the non-dominated sorting genetic algorithm-II (NSGA-II). In order to investigate the influence of the number of dwells on the optimization result, four-dwell and two-dwell temperature profiles are selected for the design variables. The optimization method obtains successfully the Pareto optimal front of the multi-objective problem in thick and ultra-thick laminates. The result shows that the cure time and maximum temperature overshoot are both reduced significantly. The optimization result further illustrates that the four-dwell cure profile is more effective than the two-dwell, especially for the ultra-thick laminates. Through the optimization of the four-dwell profile, the cure time is reduced by 51.0% (thick case) and 30.3% (ultra-thick case) and the maximum temperature overshoot is reduced by 66.9% (thick case) and 73.1% (ultra-thick case) compared with the recommended cure profile. In addition, self-organizing map (SOM) is employed to visualize the relationships between the design variables with respect to the optimization result.

/pdf/a-multi-dwell-temperature-profile-design-for-the-cure-of-4m481dbu70.pdf

A multi-dwell temperature profile design for the cure of thick CFRP composite laminates

Micro-mechanical modeling study of the influence of cure process on the interfacial cracking of Z-pinned laminates

In this study, the micro curing residual stresses of carbon fiber-reinforced thermoset polymer (CFRP) composites are evaluated using a multiscale modeling method. A thermochemical coupling model is developed at the macroscale level to obtain the distributions of temperature and degree of cure. Meanwhile, a representative volume element model of the composites is established at the microscale level. By introducing the information from the macroscale perspective, the curing residual stresses are calculated using the microscale model. The evolution of curing residual stresses reveals the interaction mechanism of fiber, matrix, and interphase period during the curing process. Results show that the curing residual stresses mostly present a tensile state in the matrix and a compressive state in the fiber. Furthermore, the curing residual stresses at different locations in the composites are calculated and discussed. Simulation results provide an important guideline for the analysis and design of CFRP composite structures.

Xinyu Hui

Papers

An integrated modeling of the curing process and transverse tensile damage of unidirectional CFRP composites

Microscale viscoplastic analysis of unidirectional CFRP composites under the influence of curing process

A multi-dwell temperature profile design for the cure of thick CFRP composite laminates

Micro-mechanical modeling study of the influence of cure process on the interfacial cracking of Z-pinned laminates

Multiscale model of micro curing residual stress evolution in carbon fiber-reinforced thermoset polymer composites