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Acta Mechanica Solida Sinica
Journal Prestige (SJR): 0.542  Citation Impact (citeScore): 1 Number of Followers: 8  Hybrid journal (It can contain Open Access articles)ISSN (Print) 0894-9166 - ISSN (Online) 1860-2134 Published by Springer-Verlag  [2468 journals]
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- An Arbitrary Polygonal Stress Hybrid Element for Structural Dynamic
Response Analysis-
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Abstract: Abstract This paper constructs a new two-dimensional arbitrary polygonal stress hybrid dynamic (APSHD) element for structural dynamic response analysis. Firstly, the energy function is established based on Hamilton’s principle. Then, the finite element time–space discrete format is constructed using the generalized variational principle and the direct integration method. Finally, an explicit polynomial form of the combined stress solution is give, and its derivation process is shown in detail. After completing the theoretical construction, the numerical calculation program of the APSHD element is written in Fortran, and samples are verified. Models show that the APSHD element performs well in accuracy and convergence. Furthermore, it is insensitive to mesh distortion and has low dependence on selecting time steps.
PubDate: 2023-09-27
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- A Design of Tunable Band Gaps in Anti-tetrachiral Structures Based on
Shape Memory Alloy-
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Abstract: Abstract Benefitted from the properties of band gaps, elastic metamaterials (EMs) have attracted extensive attention in vibration and noise reduction. However, the width and position of band gaps are fixed once the traditional structures are manufactured. It is difficult to adapt to complex and changeable service conditions. Therefore, research on intelligent tunable band gaps is of great importance and has become a hot issue in EMs. To achieve smart control of band gaps, a design of tunable band gaps in anti-tetrachiral structures based on shape memory alloy (SMA) is proposed in this paper. By governing the phase transition process of SMA, the geometric configuration and material properties of structures can be changed, resulting in tunable band gaps. Therein, the energy band structures and generation mechanism of tunable band gaps in different states are studied, realizing intelligent manipulation of elastic waves. In addition, the influence of different geometric parameters on band gaps is investigated, and the desired bandgap position can be customized, making bandgap control more flexible. In summary, the proposed SMA-based anti-tetrachiral metamaterial provides valuable reference for the application of SMA materials and the development of EMs.
PubDate: 2023-09-27
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- Shock Characteristics and Protective Design of Equipment During Spacecraft
Docking Process-
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Abstract: Abstract The shock loads generated by spacecraft during docking can cause functional failure and structural damage to aerospace electronic equipment and even lead to catastrophic flight accidents. There is currently a lack of systematic and comprehensive research on the shock environment of spacecraft electronic equipment due to the diversity and complexity of the shock environment. In this paper, the validity of the finite element model is verified based on the sinusoidal vibration experiment results of the spacecraft reentry capsule. The method of shock dynamic response analysis is used to obtain the shock environment of electronic equipment under different shock loads. The shock response spectrum is used to describe the shock environment of aerospace electronic equipment. The results show that the resonance frequency error between the sinusoidal vibration experiment and the model is less than 4.06%. When the docking relative speed of the reentry capsule is 2 m/s, the shock response spectrum values of one of the equipment are 30 m2/s, 0.67 m/s, and 0.059 m, respectively. The wire rope spring on the mating surface can provide vibration isolation and shock resistance. An increase in spring damping coefficient results in a decrease in the amplitude and time of the vibration generated. An increase in spring stiffness reduces the input of shock load within a certain range. These research results can provide guidance for the design and evaluation of shock environmental adaptability of aerospace electronic equipment.
PubDate: 2023-09-21
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- Nonlinear Bifurcation and Post-buckling Analysis of Cylindrical Composite
Stiffened Laminates Based on Weak Form Quadrature Element Method-
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Abstract: Abstract This paper presents a weak form quadrature element formulation in the analysis of nonlinear bifurcation and post-buckling of cylindrical composite stiffened laminates subjected to transverse loads. A total Lagrangian updating scheme is used in combination with arc-length method, and the branch-switching method is adopted to identify the whole post-buckling procedure of the laminates. The formulation of the shell model and beam model are based on the basic concept of Ahmad. The coincidence of discrete nodes and integration points in quadrature element endows it with compactness and conciseness in the nonlinear buckling analysis of the cylindrical stiffened laminates. Several numerical examples are firstly presented to verify the effectiveness and accuracy of present formulation. Parametric studies on the effects of the height-to-breadth ratio, lamination schemes, positions, distribution, number of the stiffeners on the bifurcation and post-buckling behavior are performed.
PubDate: 2023-09-18
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- Bending of a Saturated Ferromagnetoelastic Plate Under a Local Mechanical
Load-
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Abstract: Abstract We study the bending of a magnetically saturated ferromagnetoelastic plate. The plate is rectangular and simply-supported along its edges. It is under a local distribution of normal mechanical load on its top surface, simulating a mechanical probe or manipulation of the magnetization field. The three-dimensional equations of saturated ferromagnetoelasticity for small fields superposed on finite biasing fields due to spontaneous magnetization are used. The plate is effectively piezomagnetic under the biasing fields. A trigonometric series solution is obtained. The perturbation of the magnetization field by the mechanical load is calculated and examined. It is found that the magnetization is sensitive to the mechanical load, particularly near the loading area. The perturbation of the magnetization is found to be associated with the transverse shear stresses in bending.
PubDate: 2023-09-08
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- Sound Reduction Control in Acoustic Enclosure with Air Ventilation
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Abstract: Abstract An acoustic enclosure system with both interior sound reduction and air ventilation is designed and demonstrated. The system consists of a rectangular enclosed space coupled with ventilated metamaterials and microperforated panels (MPPs). By modeling the ventilated metamaterial as an impedance boundary condition, an analytic model is developed to characterize the frequency response of interior acoustic fields and evaluate the sound reduction performance of MPP structures. Numerical simulations are conducted to validate the accuracy of the theoretical model. It is found that the resonance response of the enclosure system can be suppressed by proper arrangement of the MPPs. Even with open area for airflow, the system still possesses good sound isolation originating from the low-transmission behavior of the ventilated metamaterial. The proposed model system may find potential applications in noise control engineering.
PubDate: 2023-08-28
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- Size Effect on the Fracture Strength and Toughness of Nano-cracked CoSb3:
A Molecular Dynamics Study-
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Abstract: Abstract Molecular dynamics simulations are implemented to study the mechanical fracture of CoSb3 with penetrated nanocracks under the mode-I stress. The crack surface and crack front direction are (100) and [001], respectively. It is found that, at a fixed initial crack length, the fracture strength varies with the sample size, but the calculated value of fracture toughness KIC, by employing the classical formula of linear elastic fracture mechanics, maintains constant. When the crack is short in length relative to the sample, the variation of the fracture strength with the initial crack length is well fitted mathematically, and the extrapolation shows rationality even up to the macroscale. More general analyses reveal that, the fracture toughness increases monotonically with increasing the initial crack length until reaching the limit, and the increment is particularly noticeable below 36 nm. Furthermore, different atomic configurations at the crack tip are considered, which show an evident influence on the strength of nano-cracked CoSb3.
PubDate: 2023-08-28
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- Accelerating Optimization Design of Bio-inspired Interlocking Structures
with Machine Learning-
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Abstract: Abstract Structural connections between components are often weak areas in engineering applications. In nature, many biological materials with remarkable mechanical performance possess flexible and creative sutures. In this work, we propose a novel bio-inspired interlocking tab considering both the geometry of the tab head and neck, and demonstrate a new approach to optimize the bio-inspired interlocking structures based on machine learning. Artificial neural networks for different optimization objectives are developed and trained using a database of thousands of interlocking structures generated through finite element analysis. Results show that the proposed method is able to achieve accurate prediction of the mechanical response of any given interlocking tab. The optimized designs with different optimization objectives, such as strength, stiffness, and toughness, are obtained efficiently and precisely. The optimum design predicted by machine learning is approximately 7.98 times stronger and 2.98 times tougher than the best design in the training set, which are validated through additive manufacturing and experimental testing. The machine learning-based optimization approach developed here can aid in the exploration of the intricate mechanism behind biological materials and the discovery of new material designs boasting orders of magnitude increase in computational efficacy over conventional methods.
PubDate: 2023-08-23
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- Analysis and Prediction of Hole Penetrated in Thin Plates under
Hypervelocity Impacts of Cylindrical Projectiles-
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Abstract: Abstract The hole penetrated in thin metallic plates due to hypervelocity impacts of cylindrical projectiles was analyzed by experimental method. The projectile caused a hole-expanding effect when penetrating the target plate because of dynamic shear failure and extrusion. A new empirical model was presented to predict the perforation diameter in thin plates impacted by high-velocity cylindrical projectiles. The fitting coefficients resulted in a root-mean-square of 0.0641 and a correlation coefficient of 0.991. The errors between the predicted and the experimental values were less than 7.251%, and less than 4.705% for 93.333% cases of the dataset. The accuracy of the proposed model is much higher than that of Hill’s model. Compared with historical equations, the new model is more accurate and can well describe the variations of different parameters with the normalized penetrated hole. The model takes into account the strength of materials, which contributes to the excellent results. This paper could provide important theoretical support for the analysis of the perforation process and its mechanism.
PubDate: 2023-08-16
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- Energy Absorption Performance of Bionic Multi-cell Tubes Inspired by
Shrimp chela-
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Abstract: Abstract This research introduced the design, analysis and optimization of bionic shrimp chela multi-cell tubes (BSCMTs) in bending by embedding an arthropod's microstructure inside a thin-walled square structure. A three-point impact bending finite element model was, in the first instance, correlated with physical tests and then modified to assess the energy absorption performance of bionic multi-cell tubes considering initial peak force, specific energy absorption and mean crushing force. Following a complex proportional assessment (COPRAS) approach and optimization phases, results demonstrated that the BSCMT with a W-shape section had the best energy absorption characteristics and should be considered in future as a possible contender for vehicle B-pillar structures that are subjected to bending and require excellent energy absorption properties to protect the occupants in high-speed impact collisions.
PubDate: 2023-08-10
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- Semi-analytical Modeling of the Influence of Macro Bending Effects on
Micro Contact-Inhomogeneity Problems-
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Abstract: Abstract This study examines the effects of macroscopic bending and microscopic contact loading in inhomogeneous materials using a semi-analytical model based on Eshelby's equivalent inclusion method. The model accounts for bending effects through the beam theory, with bending stress included in the Eshelby's equivalent inclusion equations. The macroscopic displacement resulting from bending effects is incorporated into the microscopic contact solver, and the final displacement is determined using the conjugate gradient method in an iterative solution. Computational efficiency can be improved by incorporating the discrete convolution and fast Fourier transform. The core scheme is validated using the finite element method, yielding accurate and efficient results for bending-contact problems in inhomogeneous materials. Simulations reveal the interplay between bending, contact loading, and inhomogeneity, as stress around the inhomogeneity alters and the stress concentration area expands under increasing bending moments. Conversely, low-magnitude negative bending moments reduce both contact pressure and stress around the inhomogeneity. The position where inhomogeneities are least affected shifts from the neutral surface depending on the coupling effect. The model provides a valuable bridge for connecting the macroscopic bending effect and microscale contact-inhomogeneity problems by visualizing stress fields and assessing pressure distributions.
PubDate: 2023-08-10
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- Hybrid Finite Element Method Based on Polygon-Quadtree Meshes for Heat
Transfer and Thermal Elastic Analysis-
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Abstract: Abstract A steady-state thermal hybrid element model is proposed to calculate particle-reinforced composites divided by an improved quadtree mesh. The functional of hybrid flux finite element method (HF-FEM) is constructed using the weighted residual method. This functional independently assumes a heat flux field in the cell domain and a temperature field along cell boundaries. The construction of a universal heat flux function is put forward, which is approximated by a complete polynomial, and the temperature at the cell boundary is obtained by linear interpolation. Also, the hybrid stress finite element method (HS-FEM) is constructed to solve the thermal stress. In this paper, an improved quadtree grid that can accurately describe the shape of elliptical inclusions is built. By comparing several numerical examples with the traditional FEM, it is demonstrated that the hybrid element of the thermal analysis proposed in this paper is practical.
PubDate: 2023-08-03
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- Tuning of Multi-stability Profile and Transition Sequence of Stacked
Miura-Origami Metamaterials-
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Abstract: Abstract Multi-stable origami structures and metamaterials possess unique advantages and could exhibit multiple stable three-dimensional configurations, which have attracted widespread research interest and held promise for applications in many fields. Although a great deal of attention has been paid to the design and application of multi-stable origami structures, less knowledge is available about the transition sequence among different stable configurations, especially in terms of the fundamental mechanism and the tuning method. To fill this gap, with the multi-stable dual-cell stacked Miura-ori chain as a platform, this paper explores the rules that govern the configuration transition and proposes effective methods for tuning the transition sequence. Specifically, by correlating the energy evolution, the transition paths, and the associated force–displacement profiles, we find that the critical extension/compression forces of the component cells play a critical role in governing the transition sequence. Accordingly, we summarize the rules for predicting the transition sequence: the component cell that first reaches the critical force during quasi-static extension or compression will be the first to undergo a configuration switch. Based on these findings, two methods, i.e., a design method based on crease-stiffness assignment and an online method based on internal pressure regulation, are proposed to tune the stability profile and the transition sequence of the multi-stable origami structure. The crease-stiffness design approach, although effective, cannot be employed for online tuning once the prototype has been fabricated. The pressure-based approach, on the other hand, has been shown experimentally to be effective in adjusting the constitutive force–displacement profiles of the component cells and, in turn, tuning the transition sequence according to the summarized rules. The results of this study will advance the state of the art of origami mechanics and promote the engineering applications of multi-stable origami metamaterials.
PubDate: 2023-08-01
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- Foldcore Structures with Origami Initiators for Energy-Absorbing Sandwich
Panels-
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Abstract: Abstract Origami foldcore structures can be used in thin-walled sandwich panels to provide unique advantages over traditional honeycomb structures. For instance, their continuously connected space is available for flowing through cooling liquid or compact pipeline placement. However, origami foldcores suffer from relatively low-energy absorption. This paper proposes a new design of energy-absorbing foldcore structures for sandwich panels, including the geometric design, experimental tests, numerical parametric study, and theoretical estimation of energy absorption. Origami initiators are introduced to the Miura foldcores to induce a failure mode with more transverse folds, which is not common for regular foldcore structures. As a result, 60% higher energy absorption and tunable load uniformity can be achieved.
PubDate: 2023-08-01
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- Editorial for the Special Issue on “Origami/Kirigami Structures and
Engineering Applications”-
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PubDate: 2023-07-17
DOI: 10.1007/s10338-023-00411-1
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- Stiffness-Tunable Origami Structures via Multimaterial Three-Dimensional
Printing-
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Abstract: Abstract Origami structure has been employed in many engineering applications. However, there is currently no strategy that can systematically achieve stiffness-tunable origami (STO) structures through proper geometric design. Here, we report a strategy for designing and fabricating STO structures based on thick-panel origami using multimaterial 3D printing. By adjusting the soft hinge position, we tune the geometric parameter ψ to program the stiffness and strength of origami structures. We develop origami structures with graded stiffness and strength by stacking Kresling origami structures with different ψ. The printed structures show great cyclic characteristics and deformation ability. After optimizing combinations of structures with different ψ, the multi-layer Kresling STO structures can effectively reduce the peak impact, showing a good energy absorption effect. The proposed approach can be implemented in various origami patterns to design and tune the mechanical properties of origami structures for many potential applications.
PubDate: 2023-06-27
DOI: 10.1007/s10338-023-00403-1
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- Magnetic Kirigami by Laser Cutting
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Abstract: Abstract Magnetic kirigami with tunable configurations under magnetic actuation is of significant interest in various emerging fields. However, there remains a grand challenge to develop magnetic kirigami with a facile fabrication strategy, programmable magnetization, and functionality. In this work, we present a novel magnetic kirigami that is readily fabricated by the laser cutting technique. The magnetic kirigami consists of an array of magnetic microplates, each with a programmed magnetization. By applying an actuation magnetic field, each microplate can rotate and even flip, allowing for predesigned kirigami configurations. By further coating the surface of the microplate array, the magnetic kirigami can be programmed with functionality. We demonstrate a potential application of information encryption by engineering magnetic kirigami into a magneto-responsive QR code. Providing a simple fabrication strategy, our work paves the way for other applications of magnetic kirigami.
PubDate: 2023-06-23
DOI: 10.1007/s10338-023-00394-z
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- Volume Optimisation of Multi-stable Origami Bellows for Deployable Space
Habitats-
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Abstract: Abstract Origami bellows are formed by folding flat sheets into closed cylindrical structures along predefined creases. As the bellows unfold, the volume of the origami structure will change significantly, offering potential for use as inflatable deployable structures. This paper presents a geometric study of the volume of multi-stable Miura-ori and Kresling bellows, focusing on their application as deployable space habitats. Such habitats would be compactly stowed during launch, before expanding once in orbit. The internal volume ratio between different deployed states is investigated across the geometric design space. As a case study, the SpaceX Falcon 9 payload fairing is chosen for the transportation of space habitats. The stowed volume and effective deployed volume of the origami space habitats are calculated to enable comparison with conventional habitat designs. Optimal designs for the deployment of Miura-ori and Kresling patterned tubular space habitats are obtained using particle swarm optimisation (PSO) techniques. Configurations with significant volume expansion can be found in both patterns, with the Miura-ori patterns achieving higher volume expansion due to their additional radial deployment. A multi-objective PSO (MOPSO) is adopted to identify trade-offs between volumetric deployment and radial expansion ratios for the Miura-ori pattern.
PubDate: 2023-06-23
DOI: 10.1007/s10338-023-00401-3
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- The Compressive and Shear Characteristics of Miura-ori Forms as Core
Materials of Sandwich Structures-
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Abstract: Abstract The mechanical properties of Miura-ori foldcore metamaterials were studied using finite element simulations. The responses of foldcores with various topological parameters to quasi-static out-of-plane compression and shear loading were analyzed using the relative density as a governing parameter. The non-unique relationships between the core density and the materials’ strength in the examined loading directions were revealed, pointing out the strong influence of the Miura-ori topology. Linear relationships were established between the elastic moduli and relative densities of the Miura-ori metamaterials while power-law functions of the relative density with different exponent constants were established for the strength in different loading directions. It was shown that the Miura-ori materials possess the highest strength under shear in the \({X}_{1}-{X}_{3}\) plane and it increases with the increase in the relative density. However, this characteristic is strongly influenced by the sector angle \(\alpha \) . In general, the difference between the two shear strengths increases when increasing the relative density by using thicker cell walls. It is noted that the strength of the Miura-ori materials as a function of the relative density is nearly constant with respect to the cell dimensions if the values of folding angle \({\gamma }_{0}\) and sector angle \(\alpha \) are given. The mechanical characteristics of the Miura-ori material with equal relative density, which exhibits the highest strength among the analyzed origami models, are compared with the out-of-plane compression and shear responses of prismatic hexagonal honeycomb. It is observed that compression and shear responses of the honeycomb outperform the Miura-ori foldcore in all loading directions when considering large deformations.
PubDate: 2023-06-16
DOI: 10.1007/s10338-023-00405-z
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- Imperfection Insensitivity of Origami-Inspired Tubular Structures
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Abstract: Abstract Axially loaded tubular structures are known to be highly sensitive to initial geometric imperfections, which can significantly reduce their design bearing capacity. To address this issue, this study explores the potential of an origami-inspired design for tubular structures to achieve a lower sensitivity to imperfections. The study considers various designs, including diamond-shaped, pyramid-shaped, new Kresling, and pre-embedded rhombic origami tubes, and employs knockdown factors (KDFs) to illustrate the reduction of the design bearing capacity of these structures with initial geometric imperfections for safety purposes. Finite element analysis shows that some of the origami tubes have superior design bearing capacity, mass efficiency, and KDFs when compared to standard circular tubes. Among the origami tubes considered, the rhombic tube demonstrates the best performance and is further studied through parametric analyses of geometric design, aspect ratio, and wall thickness to achieve additional performance enhancements. Furthermore, the superior performance of the rhombic tube is evaluated and verified for various loading scenarios, including eccentric compression and compression-torsion combination. The findings of this study provide a promising approach to designing and fabricating imperfection-insensitive tubes using advanced processing technologies such as additive manufacturing. This work can potentially lead to the development of innovative tubular structures with enhanced safety and reliability in various engineering applications.
PubDate: 2023-06-14
DOI: 10.1007/s10338-023-00402-2
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