Stiffness Properties Research Articles

Flexible and lightweight carbon fiber/silicone resin composites with the “soft-rigid” structural interface for thermostable and antistatic applications

To avoid a large difference in modulus between carbon fiber (CF) and silicone resin (SR) and unstable thermal properties, the “soft-rigid” structural interface is constructed by coating polydopamine-polyethyleneimine@octaphenyl-silsesquioxane (PDA-PEI@octaphenyl-POSS) on the fiber surface. The tensile strength of the CF-AE@3P/SR composite was 24.35 % higher than that of the unmodified CF/SR. The mechanism of mechanical enhancement revealed that the rigid layer with nanoparticles effectively deflected the crack and prolonged the path, and the hydrogen bonds and van der Waals forces helped disperse the stress concentration at the interface. The defects in the soft–rigid structural interface were reduced, and the decomposition of the fibers and composites was effectively inhibited, thereby increasing the heat transmission in the composites. After heating for 20 s on the heating plate at 200 °C, the surface temperature of the CF-AE@3P/SR composite was 155.4 °C, which is higher than that of the unmodified CF/SR (131.4 °C). Therefore, the thermal stability of the CF-AE@3P/SR composites was significantly improved compared to that of unmodified CF/SR after holding at 350 °C for 3 h. Surface resistance analysis showed that the soft–rigid modification maintained the antistatic properties of the composites at room and high temperatures. It was also found that the CF-AE@P/SR composites exhibited good flexibility, lightweight, and hardness for application in sealing and electronic components. This work provides ideas for forming a seamless transition and effective bonding between high-modulus carbon fibers and a low-modulus elastomer matrix, increasing the thermal stability and mechanical properties, and maintaining the flexibility, stiffness, lightweight, and antistatic properties of composites at high temperatures

The Abrasive Water Jet Cutting Process of Carbon-Fiber-Reinforced Polylactic Acid Samples Obtained by Additive Manufacturing: A Comparative Analysis

Carbon-fiber-reinforced polymer (CFRP) composites are widely used across industries due to their enhanced strength and stiffness properties. Fused deposition modeling (FDM) enables the cost-effective production of polymer samples, such as carbon-fiber-reinforced PLA (CFR-PLA). However, CFRP’s hardness and anisotropic nature present significant challenges in conventional machining, including rapid tool wear and thermal sensitivity. Consequently, abrasive water jet machining (AWJM) has proven to be an effective alternative for machining CFRP materials, offering benefits such as reduced tool wear, minimized thermal damage, and improved cutting quality. This study focuses on a comparative analysis of the effects of AWJM parameters on PLA and CFR-PLA samples, specifically to evaluate the influence of carbon fiber reinforcement on machining performance. The findings highlight the critical role of reinforcements in machining behavior. The results suggest that optimizing cutting parameters significantly reduces taper formation and improves machining accuracy. In particular, adjustments to process parameters resulted in lower taper angles and reduced surface roughness in the cutting zones of the CFR-PLA samples.

Performance analysis of vertical smart isolator based on magnetorheological elastomer

ABSTRACT As one of the field-dependent smart materials whose stiffness and damping properties can change instantaneously and reversibly, magnetorheological elastomer (MRE) has been extensively utilized on base isolation for vibration reduction. However, most previous studies have focused on the shear dynamic performance of MRE isolators, and there are few reports on the vertical extrusion performance of basic isolators within construction equipment. In this paper, MRE materials with strong bearing capacity and suitable vertical stiffness were fabricated by comprehensively considering the selection of raw materials, particle ratio, and sample size. The tension-compression viscoelasticity of the prepared MRE under varying magnetic fields and strain amplitudes was experimentally evaluated using an MRE axial MR testing system. Eventually, a single-degree-of-freedom dynamic test rig for vibration isolation of equipment in buildings, which integrates a vertical isolator with MRE as the core component, was constructed to perform a series of experimental investigations on the alterable frequency vibration capability of the designed MRE vertical isolator. The test results reveal that the controllable stiffness-damping properties of the prepared MRE in the axial tension-compression mode can enable the developed vertical isolator to exhibit superior frequency shifting and vibration attenuating characteristics in structural vibration.

Design and Evaluation of a Novel Variable Stiffness Hip Joint Exoskeleton.

An exoskeleton is a wearable device with human-machine interaction characteristics. An ideal exoskeleton should have kinematic and kinetic characteristics similar to those of the wearer. Most traditional exoskeletons are driven by rigid actuators based on joint torque or position control algorithms. In order to achieve better human-robot interaction, flexible actuators have been introduced into exoskeletons. However, exoskeletons with fixed stiffness cannot adapt to changing stiffness requirements during assistance. In order to achieve collaborative control of stiffness and torque, a bionic variable stiffness hip joint exoskeleton (BVS-HJE) is designed in this article. The exoskeleton proposed in this article is inspired by the muscles that come in agonist-antagonist pairs, whose actuators are arranged in an antagonistic form on both sides of the hip joint. Compared with other exoskeletons, it has antagonistic actuators with variable stiffness mechanisms, which allow the stiffness control of the exoskeleton joint independent of force (or position) control. A BVS-HJE model was established to study its variable stiffness and static characteristics. Based on the characteristics of the BVS-HJE, a control strategy is proposed that can achieve independent adjustment of joint torque and joint stiffness. In addition, the variable stiffness mechanism can estimate the output force based on the established mathematical model through an encoder, thus eliminating the additional force sensors in the control process. Finally, the variable stiffness properties of the actuator and the controllability of joint stiffness and joint torque were verified through experiments.

Harnessing plasticity in sequential metamaterials for ideal shock absorption.

Mechanical metamaterials exhibit interesting properties such as high stiffness at low density1-3, enhanced energy absorption3,4, shape morphing5-7, sequential deformations8-11, auxeticity12-14 and robust waveguiding15,16. Until now, metamaterial design has primarily relied on geometry, and materials nonlinearities such as viscoelasticity, fracture and plasticity have been largely left out of the design rationale. In fact, plastic deformations have been traditionally seen as a failure mode and thereby carefully avoided1,3,17,18. Here we embrace plasticity instead and discover a delicate balance between plasticity and buckling instability, which we term 'yield buckling'. We exploit yield buckling to design metamaterials that buckle sequentially in an arbitrary large sequence of steps whilst keeping a load-bearing capacity. We make use of sequential yield buckling to create metamaterials that combine stiffness and dissipation-two properties that are usually incompatible-and that can be used several times. Hence, our metamaterials exhibit superior shock-absorption performance. Our findings add plasticity to the metamaterial toolbox and make mechanical metamaterials a burgeoning technology with serious potential for mass production.

Fabrication of Green Composite Materials Using the Weight Sum Method (WSM) Method

The quest for sustainable materials the investigation into natural fibers for composite materials has been prompted by this development., aiming to reduce the environmental impact of traditional synthetic composites. In this study, we investigate the potential of flax, hemp, jute, kenaf, and ramie fibers as reinforcements in green composites fabricated using the Water Soaking Method (WSM). The evaluation parameters considered include density (g/cm3), fiber diameter (μm), tensile strength (MPa), Young’s modulus (GPa), and elongation at break (%). Through meticulous experimentation and analysis, it is revealed that jute emerges as the frontrunner among the alternatives, exhibiting superior performance across multiple evaluation parameters. Jute-based green composites demonstrate commendable strength and stiffness properties, coupled with a moderate density, making them promising candidates for various structural applications. Conversely, kenaf fiber-based composites exhibit the lowest performance in terms of evaluated parameters, indicating potential limitations in its suitability for high-performance applications. The comparative assessment underscores the significance of material selection in composite fabrication, emphasizing the diverse mechanical properties exhibited by different natural fibers. Furthermore, the utilization of the WSM method showcases its effectiveness in producing green composites with desirable characteristics, signifying its potential as a viable manufacturing technique for sustainable materials. eco-friendly composites, highlighting the importance of considering multiple factors such as fiber type and fabrication method in achieving optimal performance and environmental sustainability in composite materials. Further research may delve into refining fabrication techniques and exploring novel fiber combinations applications.

Stochastic optimization of a mass-in-mass cell with piecewise hybrid nonlinear–linear restoring force

This article investigates the optimization under uncertainty of a mass-in-mass meta-cell for its potential use within a metamaterial. The specificity of the proposed mass-in-mass system stems from the hybrid nonlinear–linear stiffness at the inner level. It is well known that these systems are highly sensitivity to small perturbations in loading conditions or design parameters. In fact, the sensitivity is such that the system can exhibit discontinuous behaviors. Therefore the proposed optimization approach not only accounts for sources of uncertainties but also can handle discontinuous responses. The objective of the stochastic optimization is to find the stiffness properties of the mass-in-mass system which minimize the expected value of a specific efficiency metric. In order to better understand the system’s dynamic behavior and the origins of the discontinuities, slow invariant manifolds and frequency response curves are provided. The efficiency of the optimized system with hybrid stiffness is compared with that of a similar optimized system featuring pure cubic nonlinearity.

Initial monitoring of a six-story lightweight timber frame building under different environmental conditions

AbstractThis study presents a comprehensive investigation of the dynamic behavior of a six-story lightweight timber frame building through periodic and continuous ambient vibration tests. Seasonal changes in temperature and relative humidity can influence the dynamic response of timber buildings, by affecting stiffness, strength, and connection properties due to changes in moisture content. Systematic tests were performed from October 2022 until May 2024 to identify natural frequencies, damping ratios, and mode shapes of the building using five battery-driven data acquisition units equipped with 15 uni-axial accelerometers. Two different only-output frequency and time domain Operational Modal Analysis (OMA) methods were used to evaluate the dynamic properties of the building. Additionally, the building has been continuously monitored with temperature and humidity sensors since its construction. Results obtained from the periodic measurements highlighted the need for a permanent system to capture the transient changes in the modal parameters. A complementary permanent system to record the accelerations at the roof level was installed in May 2024. The modal parameters from in situ measurements were compared with those obtained from the Finite Element (FE) model of the structure. The FE model, calibrated through a multi-stage approach, incorporating non-structural elements, and varying imposed loads, showed good agreement with experimental data. Comparative analysis of the results obtained under different temperature and humidity conditions showed the effect of the environmental conditions on the building dynamics properties, for both periodic and permanent measurements. This study highlights the importance of continuous monitoring and detailed FE modeling in understanding the dynamic properties and long-term structural behavior under varying conditions. This information can be used to ensure that the building meets safety and performance requirements and to identify potential issues that may need to be addressed during the design and maintenance phases.

Trio/hybrid fiber effect on the geopolymer reinforced concrete for flexural and shear behavior

AbstractGeopolymer concrete (GC) is an innovative and sustainable type of composite resulting from the chemical reaction between waste materials containing and alkaline activators. The researchers have been focused to reduction of the greenhouse‐gas release, especially during the production of cement. Although numerous studies have been conducted on alkali‐activated cement or GC at the material level, there is limited research in the literature on the structural performance of reinforced GC members. The aim of this study is to investigate the effect of fiber combination on the shear and flexural performance of RC beams with maximum and minimum reinforcement ratio. To investigate the shear and flexural behavior of GC beam, four‐point and three‐point tests were performed on 12 GC with hybrid fibers, 4 GC with trio fibers, and 2 GC fiber‐free as references beams. The test parameters were the combination of fibers (steel, glass, carbon, and basalt), the longitudinal reinforcement ratio, and loading type. The key test results include the load‐deflection behavior, characteristics of the cracks, the effect of fiber type on the shear and flexural performance, ductility and stiffness properties, microstructure, the strain in the concrete, and the bars and code predictions. The test results showed that as expected, reducing the longitudinal reinforcement ratio decreased the strength, but the decrease in strength was tolerated by using different types of fibers. The use of trio fibers in beams under bending increased the strength capacity, considerably. Finally, the capacity prediction performance of current codes, that is, GB50010, EuroCode‐2, TS500, and ACI318, were also examined, and the calculations resulted that the current code equations had a percentage error of approximately 25% and 82% on average for flexural and shear, respectively, although EuroCode‐2 equations performed slightly better.

Comprehensive Analysis of the Effect of Braiding Angle on the Wettability and Mechanical Properties of 3D Braided Carbon Fiber Fabric-Reinforced Composites

Fiber-reinforced composites are designed to enhance strength, stiffness, and lightweight properties. However, while the use of continuous fibers offer substantial performance benefits it presents challenges in achieving complex configurations. This study focused on evaluating the effects of different braiding angles on the mechanical properties of braided fabric-reinforced composites (B-CFRP). Continuous fiber tows were braided around a mandrel, with meticulous control over the key process parameters to ensure consistency. The composites were then processed using the Vacuum Assisted Resin Transfer Molding (VARTM) technique to achieve optimal impregnation of the resin. Mechanical properties, including tensile, flexural, compressive strength, interlaminar shear strength (ILSS), and impact strength, were performed to establish the relationship between resin impregnation and mechanical properties with different braid angles. Additionally, resin flow experiments and scanning electron microscopy (SEM) analysis were conducted to investigate how variations in braiding angle influence fiber arrangement, resin distribution, and fracture behavior. These insights aim to guide the design and manufacturing of high-performance composites.

A data-driven microstructure-based model for predicting circumferential behavior and failure in degenerated human annulus fibrosus

The degeneration of the intervertebral disc annulus fibrosus poses significant challenges in understanding and predicting its mechanical behavior. In this article, we present a novel approach, enriched with detailed insights into microstructure and degeneration progression, to accurately predict the mechanics of the degenerated human annulus. Central to this framework is a fully three-dimensional continuum-based model that integrates hydration state and multiscale structural features, including proteoglycan macromolecules and interpenetrating collagen fibrillar networks across various hierarchical levels within the multi-layered lamellar/inter-lamellar soft tissue, capable of sustaining deformation-induced damage. To ensure accurate and comprehensive predictions of the degenerated annulus mechanical behavior, we establish a data-driven correlation between disc degeneration grade and individual age, which influences the composition and mechanical integrity of annulus constituents while accounting for regional variations. The methodology includes a thorough identification of age- and grade-related evolutions of model inputs, followed by a detailed quantitative evaluation of the model predictive capabilities, with a focus on circumferential behavior and failure. The model successfully replicates experimental data, accurately capturing stiffness, transverse response (Poisson's ratio), and ultimate properties across different annulus regions, while also accommodating the modulation of the age/grade relationship. The reduction rates between normal and severe degeneration align reasonably well with experimental data, with the inner region exhibiting the largest decrease in stiffness (34.63%) and no significant change observed in the outer region. Failure stress drops considerably in both regions (49.86% in the inner and 45.33% in the outer), while failure strain decreases by 36.39% in the outer and 24.74% in the inner. Our findings demonstrate that the proposed framework significantly enhances the predictive accuracy of annulus mechanics across a spectrum of degeneration levels, from normal to severely degenerated states. This approach promises improved predictive accuracy, deeper insights into disc health and injury risk, and a robust foundation for further research on the impact of degeneration on disc integrity. Statement of SignificanceUnderstanding and predicting the mechanical behavior of degenerated human annulus fibrosus remains a significant challenge due to the complex interplay of structural, biochemical, and age-related factors. This study presents a microstructure-based approach to address this challenge by integrating hydration state, detailed structural features across hierarchical scales, and deformation-induced damage and failure, alongside age-related changes and degeneration grade factors. This approach enables accurate simulations of annulus mechanics across regions, with model results thoroughly compared to available data, reinforcing its applicability in capturing degeneration effects. By capturing the intricate interactions between microstructure and mechanical behavior in degenerated discs, the model lays a strong foundation for improving clinical assessments and guiding future treatment strategies for disc-related conditions.

Impact of Hydrogen Cage Occupancy on the Mechanical Properties and Elastic Anisotropies of sII Hydrates

In this study, we investigate the composition-dependent mechanical properties and elastic anisotropies of sII hydrogen hydrates using first-principles method. The evaluation of the elastic moduli and their direction dependency is achieved by computing the second-order elastic constants (SOECs) of the unit lattice. The various trends of elastic constants with the hydrogen composition of the cages introduces variations in the bonding strength, compressibility, stiffness, and shear properties of the structure which are captured by the Poisson's ratio, bulk, Young, and shear moduli, respectively. Elastic properties were found to be significantly influenced by the system's anisotropy, arising from the geometry of the cages and their unique arrangement within the lattice being affected by the increase in the hydrogen occupancy of the cages. The detailed analysis of elastic anisotropies revealed shifts in the strongest and weakest directions of the material with varying the hydrogen content of the cages. The Poisson's ratio captures the anisotropic bonding strengths within the crystal structure with the hydrogen composition of the lattice, explaining the reason behind the existence of strongest and weakest directions in terms of compression, tension, and shear forces. Taken together the established structure-property-composition relations will be useful in the design and optimization of hydrogen sII hydrates for energy storage applications.

The effect of prosthetic foot stiffness category on intact limb knee loading associated with osteoarthritis in people with transtibial amputation

Lower limb prosthesis users are at an increased risk of developing osteoarthritis in their intact knee. There is a scarcity of literature examining how the stiffness properties of commercially available prosthetic feet impact gait mechanics, including knee loading biomechanical variables that have been associated with the development of osteoarthritis. This study aimed to isolate the effect of commercial prosthetic foot stiffness on intact knee loading, prosthetic foot–ankle biomechanics, and user perception. Seventeen males with unilateral transtibial amputation were fit with three consecutive foot stiffness categories of a standardized energy-storing prosthetic foot in a randomized order and while blinded to foot condition. Biomechanical and self-report data were collected during level-ground walking in a motion analysis laboratory. As prosthetic foot stiffness increased, contralateral knee external adduction moment significantly decreased between stiff vs. medium and stiff vs. soft foot conditions. Prosthetic foot rollover radius increased as foot stiffness increased. However, prosthetic foot–ankle push-off peak power and work decreased as foot stiffness increased. On average, users favored the medium stiffness condition and were able to correctly identify the foot stiffness condition. Overall, these results raise questions about the relative contributions of foot stiffness and ankle push-off power to changes in contralateral knee loading. The findings contribute to our understanding of the relationships between prosthetic foot mechanical properties and gait biomechanical variables at the contralateral knee when prosthetic foot stiffness is modified without a corresponding alignment adjustment.

Three-dimensional buckling analysis of stiffened plates with complex geometries using energy element method

A novel numerical method, energy element method (EEM), is proposed for the three-dimensional (3D) buckling analysis of stiffened plates with complex geometries. The problem is formulated in a cuboidal domain, and any complex geometric stiffened plate is modeled by assigning cutouts within the cuboidal domain. The stiffened plate is considered as an energy body and is discretized using Gauss points with variable stiffness properties to simulate its energy distribution. Incorporating the extended interval integration, Gauss quadrature, variable stiffness properties, and Chebyshev polynomials, the strain energy of stiffened plates with complex geometries can be numerically simulated by putting the stiffness and thickness of Gauss points in the cutouts to zero in the cuboidal domain. Using the principle of minimum potential energy and Ritz solution procedure, the deformation and buckling behaviors of stiffened plates with complex geometries can be captured. As a result of the new formulations in EEM, new standard energy functionals and solving procedures have been developed. In addition, Gauss points are generated within the energy elements accounting for the geometric boundaries of the stiffened plate, which are characterized by level set functions. EEM is employed to investigate complex-shaped stiffened plates with straight or curvilinear stiffeners, and the results are compared to those obtained using FEM or mesh-free method. The precision, generalization, and stability of EEM are demonstrated.

Development of functionally graded structure for hip endoprosthesis stem based on lattice-type metamaterial

The paper reports on design and studies of a promising configuration of a hip endoprosthesis stem. The femoral component of the endoprosthesis is constructed based on a metamaterial produced by additive technologies, representing a periodic porous structure of variable topology. The central goal of the design procedure was to numerically determine the spatially graded relative density of the lattice structure within the implant volume by solving the optimization problem. The first stage of development comprised finite element modeling of a system with a solid implant attached, i.e., the optimization space, for seven different loading scenarios. These scenarios were constructed to represent the most typical cases of human motor activity. The second step was to determine the optimal spatial distribution of relative density of the lattice structure in the implant volume, obtained by solving the topological optimization problem under the given loading. After the optimization problem was solved, the distribution of the relative density of the lattice structure was obtained, serving as a basis for constructing a geometric model of a functionally graded porous scaffold for implantation. This result allows achieving an optimal ratio of stiffness and mass properties under the given loading conditions. The approach was verified by direct finite element modeling of the constructed lattice geometry of the implant under specific loading scenarios. Analyzing the stress fields in the volume of the endoprosthesis, we concluded that there were no critical regions in the developed structure, so the approach taken to develop the metamaterial-based endoprosthesis can be deemed correct.

Experimental characterization of acoustic damping materials

AbstractDue to their ease of use and low cost, passive damping methods are a preferred mean for the reduction of noise in many engineering applications. This applies in particular to foam materials, which exhibit good acoustic and mechanical damping properties. The selection of suitable materials is usually carried out experimentally and can be very labor‐intensive and time‐consuming. For this reason, it is helpful to develop qualified numerical methodsthat can be used for material design and selection. Hence, foam materials must be characterized experimentally in order to enable a later comparison with vibroacoustic simulations. This contribution, therefore, aims at providing suitable parameters for the use in numerical analyses and their validation. Firstly, the microstructure of a foam specimen is captured by means of a CT scan. In addition to providing the geometry for the multi‐physics simulations, this measurement is also used to determine characteristic foam features, for example, strut thickness and pore size distribution. In the second step, the frequency‐dependent stiffness and damping properties of the material are determined by a special experimental setup utilizing an electrodynamic shaker. Here, the dynamic system is approximated as a single‐mass oscillator, which is sufficiently accurate for low frequencies. These properties will later be used in the numerical model to evaluate different parameter identification approaches. In the third and last step of the experimental campaign, measurements with an impedance tube are conducted to obtain the coefficient of absorption. This material parameter is particularly suitable for comparing experiments and simulations. Finally, the correlation between the experimental results is examined to provide a deeper understanding of the foam materials.

A Review of Applications, Forms, Extraction, and Dissolution of Chitin

Background: Polymeric organic particles made by organisms or natural biopolymers, are considered as greener materials, more environmentally friendly and durable. Because of its exceptional structural properties, wide abundant, lack of toxicity, biocompatibility, simplicity of alteration and promised potentials, chitin is a sustainable material. It is composed of β(1,4)-linked N-acetyl-glucosamine units and represents the most abundant structural polysaccharide of invertebrates, including such marine phyla as sponges, corals, annelid worms, mollusks, and arthropods. This biopolymer is mostly found in the skeletal structures of invertebrates, and plays a crucial role in their rigidity, stiffness, and other mechanical properties. Chitin is recognized as one of the universal templates in biomineralization, with respect to both biocalcification and biosilicification. Conclusion: This review is concerned with chitin. For a set of uses, chitin with its derivatives are receiving more and more attention. The popularity of this plentiful biopolymer has skyrocketed in recent years. Studies on the use of chitin show that these biopolymers have a lot of potential for managing wounds, getting rid of toxic metals, farming, bone regenerative engineering, etc.

Stability Conditions and Stiffness Variability of General Tensegrity Systems with Kinematic Joints

Abstract Tensegrity systems represent promising candidate mechanisms with in-situ stiffness variability through changing the cables' prestress levels. However, prestress-based stiffness behaviors of tensegrity systems with arbitrary kinematic joints have not been analyzed systematically. This paper adopts the natural absolute coordinates for static modeling of tensegrity systems consisting of rigid members and tension elements. Then, a generic stiffness analysis method is developed to formulate the reduced-basis tangent stiffness matrix, which is found to include three parts: positive semi-definite material and geometric stiffness matrices, and an indefinite constraint stiffness matrix. Based on these findings, a systematic stability-checking procedure is derived to determine prestress and super stability, which are qualitative indicators of the softening and stiffening effects in different tensegrity systems. Then, we proceed to quantify the range of prestress-based stiffness variability by formulating semidefinite programming problems that numerically pinpoint the maximum and zero stiffness points. Furthermore, this paper reveals the composable nature of multiple self-stress states, enabling the composability of stiffness properties in mechanism designs. Several numerical examples verify the efficacy and versatility of the proposed method and demonstrate interesting stiffness behaviors of tensegrity systems with kinematic joints.

On the role of temperature in the response of air-backed composites to hydrodynamic loading: An experimental study

Understanding the role of temperature in the dynamic response of composite plates is critical for naval systems operating in extreme environments like the Arctic. Despite the advantages of composite materials in improving corrosion resistance and enabling the customization of material properties to their environment, their behavior at cold temperature, especially under dynamic loading, remains elusive. This research gap hinders the effective use of composite materials in extreme environments. Here, we study the dynamic response of air-backed fiberglass epoxy plates under hydrodynamic loading at room temperature and 4∘C. By employing digital image correlation and particle image velocimetry, we investigated the interplay between fluid–structure interactions and cold temperatures. Our findings reveal the critical role of temperature in shaping the dynamic response of air-backed composites through changes in the stiffness and damping properties. At cold temperature, the plate experiences a larger (smaller) deformation in the initial (latter) phase of the dynamic response. Furthermore, we observed a pronounced coupling between the structural response and the flow physics, with peaks of the hydrodynamic loading synchronized with the peak deflections. Our results underscore the importance of considering temperature in the design of naval systems for extreme environments, providing key insights into fluid–structure interactions at cold temperature.

Stiffness properties of regular p-bars tensegrity prisms under the compressive loading

The regular tensegrity prisms are a kind of fundamental unit, which can be formed into different configurations by different splicing approaches to achieve specific structural functions. Taking regular prisms as the research object, this article presents an analytical method for structural deformations under compressive loading. The structural parameters after loading can be obtained directly by solving the nonlinear force density equation, which simplifies the form-finding process. This article also studies the structural stiffness under different connection modes. By defining the twist angle change rate and internal force utilization rate, we can compare the relative deformation of different tensegrity prisms. The results show that the relative deformation of the three-bar prism is minimal, and it has the best stiffness.