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Bistable reeled composite shells (BRCS) have been widely used in deployable space structures due to advanced properties of light weight and large volume reduction. A finite element simulation and experimental validation to study the transition of BRCS between their two stable states are performed. In this article, multiscale representative volume element (RVE) modeling is used to compute the equivalent mechanical properties of carbon/epoxy plain woven fabrics that were utilized to construct the deployable composite laminates, followed by experimental verification. The deformation characteristics and strain energy distribution of the deployable composite shell (DCS) during snap through and coiling up are investigated using finite element analysis (FEA) and verified by strain‐gauge and digital image correlation (DIC) tests. The results show that the strain energy distribution in the snap through and coiling up of the carbon/epoxy plain woven BRCS with laminate stacking sequence of [+45/−45] is approximately symmetric. Additionally, an offset phenomena is observed during the coiling up of the BRCS in the finite element modeling. A parametric analysis is complemented to investigate effects of fiber angles on the deformation characteristics and strain energy distribution of the shell structures during snap through and coiling up. Highlights: Shell deformation during snap through and coiling up was investigated.DIC test was performed to capture the shell deformation.Strain energy distribution of the deployable composite shell was discussed.Offset phenomena are observed during the coiling up. [ABSTRACT FROM AUTHOR]

In this study, elastic metamaterial sandwich plates with axially deformed Timoshenko beam cores, considering both the out-of-plane and in-plane deformations of the face plates, are designed and the vibration band-gap properties are explored. The beam cores act as local resonators that can bear axial force, bending moment and shearing force. The finite element method (FEM) and the spectral element method (SEM) are combined to create the finite/spectral element hybrid method (FE-SEHM) for establishing the dynamic model and calculating the frequency response functions (FRFs) of the elastic metamaterial sandwich plate with axially deformed beam cores. It is observed that the metamaterial sandwich plate possesses both the axial and transverse vibration band-gaps of the beams, and the two kinds of band-gaps are independent. Compared with the metamaterial sandwich plates with rod cores, those with axially deformed beam cores have more extensive application ranges for vibration reduction. [ABSTRACT FROM AUTHOR]

A new kind of elastic metamaterial plate is designed to control the vibration and elastic wave propagation based on the band-gap mechanism. For the proposed elastic metamaterial plate, local resonant rods are periodically distributed between the two cover plates of the metamaterial plate structure. The dynamic stiffness matrix and the frequency response function of the structure under the time-harmonic excitation are obtained by the finite element and spectral element hybrid method (FE-SEHM). The experiment and simulation validations have been carried out. The effects of the material and structural parameters on the band-gap characteristics are analyzed. It is shown that the band-gaps can be computed more accurately and efficiently based on the FE-SEHM to avoid confusion between the pass-bands and band-gaps. Three band-gaps of the elastic metamaterial plate appear near the odd-order natural frequencies of the local resonant rods. Increasing the damping and mass of the local resonant rods results in the enlargement of the band-gap width, this enhances the capacity of the vibration reduction and sound isolation more effectively. [ABSTRACT FROM AUTHOR]

This paper discusses a global buckling analysis approach for sandwich plates with stiffening ribs. The approach is based on theoretical study and is implemented by the finite element method (FEM). The equilibrium equation corresponding to critical global buckling of the sandwich plate with stiffening ribs under simple supported boundary condition is established by the energy method. The critical buckling solutions for a typical rectangular sandwich plate system (SPS) with a single stiffening rib in the longitudinal direction are then investigated while varying the potential influencing factors. The shear rigidity within the inner core exerts little effect on global buckling and can be neglected. An FEM study on elastic buckling was then conducted via ANSYS software. The advantages of the SPS were highlighted via its elastic eigenvalue buckling numerical analysis with multiple stiffeners. The ultimate buckling loads were computed similarly for different influential factors. Finally, an SPS specimen was tested in a compression test. The results showed that when the rib spacing is large, the local buckling of the plates in the grillage is controllable and the SPS is more resistant to both local and global buckling. The results based on our theoretical method agreed well with those of the FEM and experimental results. [ABSTRACT FROM AUTHOR]

In this study, the ballistic performance of the composite structure was investigated and studied by experiment and finite element analysis in order to study the anti-penetration performance of a polyurethane elastomer-coated honeycomb sandwich construction. Six kinds of target plate structures with different configurations were prepared by changing the hard segment content and coating position of polyurethane elastomer. The first-stage light gas gun device is used to conduct impact experiments at various speeds, and the finite element simulation computation is performed using LS-DYNA. Based on the experimental and finite element results, the ballistic limit velocity and specific energy absorption of different target configurations were analyzed, and the failure forms, damage areas, and failure mechanisms were discussed. The findings demonstrate that the polyurethane elastomer coating enhances the honeycomb sandwich structure's ballistic limit performance by 40.6% to 51% and that the honeycomb core of the target plate with the coating on the front panel has a larger area of collapse. This fully exploits the benefits of the honeycomb structure in the energy absorption process and makes up for the weaknesses of the honeycomb sandwich structure's subpar energy absorption effect under local impact loads. Therefore, the front panel coating has better ballistic limit performance. The coated polyurethane with medium hardness demonstrated the best ballistic limit performance for the various polyurethane hardness. The ballistic limit speeds of the front panel and back panel coatings increased by 51% and 48.8% respectively, in comparison to the uncoated target plate. After comparing the structure of polyurea coating, it is found that the ballistic limit performance of polyurethane coating with medium hardness is higher than that of polyurea coating structure, and the negative growth of the ballistic limit performance of the whole structure caused by the coating of rigid polyurea on the back panel is effectively avoided. • The polyurethane-coated honeycomb structure's anti-penetration theory was studied. • Coated structures have a greater ballistic limit speed than uncoated ones. • The panel coating significantly raises the structure's resistance to penetration. • The front coating structure's core layer is extensively crushed. • The structure performs best in ballistics when the polyurethane equivalent is 1.3. • Hard polyurea coating's effect on ballistic performance degradation was reduced. [ABSTRACT FROM AUTHOR]