Search

The working environment of industrial fields where the Particulate Reinforced Composites (PRCs) are commonly used is complex. In these harsh environments, PRCs produce some nonlinear strains, such as plastic, thermal, and creep strains, which affect the performance of PRCs to some extent. In addition, the actual structure of PRCs contains a massive amount of inclusions, and the number of inclusions could reach the magnitude of millions or even tens of millions. For the large-scale numerical simulation of PRCs, ordinary displacement finite element requires a large number of meshes, which increases their computational complexity and unsolvability. For real PRCs with random particle distribution, homogenisation theory does not accurately capture the true state of stress concentration in PRCs. The Voronoi cell finite element method (VCFEM) can be a good solution to the drawbacks of the above two numerical simulation methods. The subject of the present work explores a modified complementary energy generalized function that takes the constitutive relationship of nonlinear strain into account, proposing a two-dimensional VCFEM, formulated with plastic, thermal, and creep strain. The simulation results are compared with the computed results of a commercial finite element software Marc to verify the validity and accuracy of the VCFEM. Results of the comparison show that the VCFEM has the advantages of simple meshing and faster computation under the same precision. The VCFEM, considering plastic, thermal, and creep strains proposed in this paper, lays the foundation for future large-scale numerical simulations of PRCs containing a large quantity of inclusion structures and can realistically capture the stress concentration state of PRCs. At the end of the article, the impact of the order of stress function on the calculation results is discussed. [ABSTRACT FROM AUTHOR]

• Thin-walled lenticular composite booms with different design parameters were prepared, and free-end loading experiments and coiling experiments are conducted on the established experimental platforms. • The finite element model of thin-walled lenticular composite booms are established and simulations are conducted to analyze the mechanical response during free-end loading and coiling process. • The influences of ply numbers, ply angles, fiber types and fiber contents on the performance of TLCBs were analyzed through experiments and finite element simulations. As a kind of lightweight composite structure, thin-walled lenticular booms made of fiber reinforced composite are widely used in the aerospace field because of its high stiffness in the unfolded state. In this paper, the load-bearing and coiling characteristics of the thin-walled lenticular composite booms were studied, and the effects of different design parameters and material properties were compared. Thin-walled lenticular composite booms with different ply numbers, ply angles, fiber types and fiber contents were prepared. Free-end loading experiments and coiling experiments were conducted to obtain the load-displacement curves, coiling torques and binding forces. The finite element model was established and the simulation results were compared with those of experiments. It is shown that increasing the ply number, increasing the fiber content and using fibers with lower elastic modulus can significantly enhance the load-bearing capacity of thin-walled lenticular composite booms, meanwhile reducing its coiling capacity. The booms with orthometric ply angle have greater load-bearing capacity, but the ply angle has less effect than the ply numbers, fiber types and fiber contents. The results provide feasibility for the design of thin-walled lenticular composite booms suitable for the aerospace field. [ABSTRACT FROM AUTHOR]

Pultruded Fiber-Reinforced Polymers (FRP) are innovative structural elements that are experiencing a steady increase in use for different structural applications. Due to their appealing properties that set them apart from traditional construction materials, such as magnetic transparency and excellent strength-to-weight ratio, numerous experimental and numerical studies have been performed in the last decades to assess their performance as structural components. The description of the micro- and macro-scale mechanical features of FRP elements requires multiple levels of information to be accurately characterized to predict their strength, and as a result, researchers have developed computational models with varying levels of complexity to parametrize their response and investigate design parameters through numerical simulations. This paper presents a critical review of the current state-of-the-art in numerical modeling of structural fiber-reinforced polymeric elements for the prediction of their mechanical behavior under serviceability and failure limit state conditions, with particular attention devoted to pultruded Glass Fiber Reinforced Polymers (GFRP), and their use as load-bearing structural elements. The most commonly adopted numerical methods for the solution of this set of problems range from classical Finite Element Method (FEM) approaches to eXtended Finite Element Method (XFEM), Virtual Crack Closure Technique (VCCT), Cohesive Zone Modeling (CZM), Multiscale Reduced Order Modeling (ROM), as well as Random Lattice Modeling (RLM) techniques recently developed by the co-authors. Each one of these methods has its own distinctive features and brings specific challenges and capabilities that will be presented and discussed in detail in the manuscript. This paper, therefore, aims at illustrating the reliability of existing numerical models for the simulation of FRP structural elements and draw conclusions and recommendations for future research, discussing 160 references from the available literature. [ABSTRACT FROM AUTHOR]