Ground vibration tests are conducted on spacecraft equipment prior to launch to simulate the demanding vibration loads, characterized by high amplitudes and energies, that occur during rocket launching. These vibration loads may be destructive to spacecraft equipment. Therefore, spacecraft equipment must be assessed under these demanding loads before undergoing destructive ground vibration tests. Existing

Passive vibration-driven robots need to achieve relatively high speeds from external vibrations to address practical demand. However, common vibration situations, such as automobiles and trains, often feature low-frequency, which are insufficient for such robots to move rapidly. Therefore, this paper introduces a novel design for passive vibration-driven robots incorporating an Inertia Amplification

The characterization of wheel-rail contacts is a key issue in railway system dynamics. In this work, complete formulations of a wheel-rail contact element are presented in coupling matrices, where the time-varying excitation sources, e.g., track irregularities, are coupled as the inner degrees of freedom (DOFs) with already-known values and the complex system differential equations in classical vehicle-track

Piezoelectric actuators are widely used in precision equipment because of their rapid response, high motion accuracy, and immunity to electromagnetic interference. However, the multi-scale characteristics of contact at the transmission interface between the stator and mover, along with stick-slip motion produce complex nonlinear behaviors in the mover system, resulting in difficulties in solving the

With recent advances in variable-length structures for use in soft actuation, energy harvesting, energy dissipation and metamaterials, the mathematical modelling and numerical simulation of physical systems with time-varying domains is becoming increasingly important. The planar nonlinear dynamics of one-dimensional elastic structures with variable domain is formulated from a Lagrangian approach by

Short and slack stranded metallic cables are encountered in several technical applications to connect different structures or different parts of the same structural system. A couple of relevant examples are provided by flexible-bus conductors used in high-voltage electrical substations or passive damping devices installed on overhead electrical lines, such as Bretelle dampers. Bending behavior of metallic

The modeling and parameter identification of a system with hysteresis remains a difficult task. This paper aims to develop a hysteretic model by combining with a fractional Backlash-like model and cascade forward neural network, and proposed a modified Newton-Raphson-based optimizer parameter identification method to precisely capture the nonlinear behavior of piezoelectric platform. There are three

H∞ optimization of dynamic vibration absorbers (DVAs) to minimize the maximum response amplitude of primary structures is a classical topic. The commonly used fixed-point method only provides approximate solutions requiring the primary structure is undamped. Instead, we perform exact optimization and investigate the less-reported parametric effects on optimization operability. To handle the known restrictions

Dynamic mode decomposition with control (DMDc) is a powerful data-driven method for modelling dynamical systems with inputs and outputs. However, the inability to identify oscillations and the high sensitivity to noise limit the application of standard DMDc in structural dynamics. To address this challenge, this paper proposes a novel method called scaled derivative-based DMDc (sd-DMDc) to construct

This study proposes an interval model updating method based on interval overlap ratios and Chebyshev polynomials. The interval midpoints and interval radii of the uncertain parameters are determined by solving optimization problems separately. The objective function for determining the interval midpoints is constructed based on predicted and measured data. To determine the interval radii, Chebyshev

This study presents a mathematical model to analyze the complex dynamics and rebound mechanism of the Tethered Space Net (TSN). Using the lumped mass method, a dynamic model of the TSN is developed and validated through ground swing testing. Building on this foundation, a novel predictive model is introduced to reveal the rebound mechanism of the TSN. This model incorporates TSN's momentum and energy

Auto-parametric resonance presents an internal coupling means for vibration suppression, which can efficiently suppress the vibrations and decrease the amplitude spill-over peaks on both sides of the absorption band. Nevertheless, there exist problems of the single design pattern of the oscillator-pendulum structure along with broad amplitude spill-over bands. This paper puts forward a dual auto-parametric

Crack tip fields of transiently propagating cracks along functionally gradient direction in anisotropic materials with having variations in elasticity and density are developed. The Laplace-transformed dynamic equilibrium equations with dilatation and distortion wave potentials are obtained using the complex variable method, and the higher order crack tip fields near the crack tip are obtained and

Currently, most memristor-based neural networks (MBNNs) models are switching systems with fixed jumping values, which may limit their applications. To tackle this issue, this paper first constructs a new MBNNs system based on HP memristors. Then the finite time (FT) intermittent stabilization of this MBNNs is investigated via a new finite time stability lemma and the designed no-chattering region-partitioning

Process uncertainty has a significant impact on industrial image processing. Existing deep learning methods were established on high-quality datasets without considering the uncertainty. This paper proposes lightweight spatial-channel feature disentanglement modeling with confidence evaluation for uncertain industrial images. First, spatial-channel feature disentanglement modeling inspired by tensor

Robust elastic wave propagation against bending and weak perturbations can be realized at the edges by analyzing the topological states in mechanical systems. However, both longitudinal and transverse wave components of polarized elastic waves complicate their manipulation. Current studies on the topological properties of elastic waves mainly address a single polarization component, even though the

A new theoretical model of heterogeneous soil-pile interaction (HSPI) in torsion is developed in this study to analyze the behavior of an end-bearing pile under torque. By assuming the surrounding soil as an elastic continuum following a power law variation in shear modulus depth, new governing equations are established for the torsional deformation of the continuous heterogeneous soil and pile system

This paper constructs a quad-stable system using magnets and inclined springs, and derives the magnetic force between the magnets based on the magnetic dipole hypothesis. Using the Lagrange principle, the dynamic equations of this quad-stable electromagnetic energy harvester (QEEH) are obtained. A detailed parameter analysis of the system's potential energy and restoring force is conducted, and the

This paper deals with the existence and stability of periodic attitude motion near hyperbolic precession (HP) for a dynamically symmetric rigid body (RB) with its center of mass moving along an elliptical orbit. We present the definitions of undisturbed and disturbed periodic attitude motions, and approximate analytical solutions for them are derived using the multiscale method under non-resonance

The combined supporting system of rockbolts and linings is one of the most common methods for controlling the deformation of surrounding rock in tunnels. However, current theoretical analyses typically consider the deformation control effect of only one support type. Consequently, the bearing capacity of rockbolts or linings is not fully utilized as their combined effect is not considered. Thus, this

Concrete slab tracks help shield the supporting railway earth structure from external water ingress. However, the inevitable cracks that arise during its lifespan provide a pathway for water penetration, leading to changes in the degree of saturation of the underlying support. This can affect the dynamic response of the structure, however is challenging to model due to the computational requirements

Elastic prediction scheme is essential in thermo-elastoplastic simulation; however, current methods do not incorporate nonlinear effects comprehensively and cause the inevitable 'over-reached plasticity' problem: the stress state after prediction is actually plastic, which contradicts to the theoretical foundation of the elastic prediction. An enhanced elastic prediction scheme (EEPS) is developed

The law of inheritance is the most basic and important law in genetics, which provides an important theoretical basis for explaining biological diversity and human development. However, the traditional experiments on genetic laws are time-consuming and require a lot of humans, material, and financial resources, which seriously restricts the development of genetics research. With the in-depth development

To address the limitation of many conventional grey forecasting methods that prioritize temporal dynamics analysis while often overlooking the essential spatial characteristics, we developed a multi-output discrete grey model tailored for forecasting electricity consumption in China's Yangtze River Delta, incorporating spatial effects. Specifically, we design a dynamic spatial interaction matrix to

Multi-scale structure, which is one of next-generation lightweight structures, has great development potential and application value. In this paper, we propose a concurrent topology optimization framework of multi-scale structures base on the phase-field method. In the framework, an energy-based homogenization approach is adopted to evaluate the macro effectiveness of the micro structure, and the Lagrange

Modeling the failure of structures induced by the movement of soils has consistently been one of the challenges that computational mechanics aims to address. In this study, an innovative nonlocal general particle dynamic method is established for soil-structure interaction problems. The pivotal advantage of the proposed method is its capability to achieve a comprehensive simulation from soil sliding

Water-pile-soil interaction and the three-dimensional scattered wave effect play crucial roles in the seismic response of structures built on saturated seabed subjected to vertical P-wave incidents. This study proposes a fully coupled three-dimensional continuum model of water-pile-saturated media to investigate the seismic response of the system under vertical seismic excitation. By employing Helmholtz

Particle filtering is a popular class of methods to estimate the state of non-linear non-Gaussian state-space models in an online manner. However, in practice, their application to systems described by partial differential equations is limited due to issues of particle degeneracy in arbitrarily high dimension spaces and the prohibitively high computational cost of evaluating posteriors with direct

Addressing the challenge of marine environmental pollution requires accurate forecasting systems, yet current methods relying on artificial intelligence and big data face limitations due to insufficient and inconsistent marine data. This paper proposes an integrated bottom-up prediction system featuring a grey modeling module and an optimization module. The grey modeling module introduces a novel nonlinear

Applying magnetic bearings in turbine machines can improve their performance. Yet, a new type of contact known as multilocation-rub-impact for high-speed magnetic-levitation bladed rotors becomes a prominent problem for this new type of turbomachinery. So far, the study of rub-impact faults mainly involves the rotor/stator contact at a single position. The paper aims to clarify the multilocation-rub-impact

Reinforced concrete (RC) slab structures are common in civil engineering, yet they are susceptible to creep under sustained loading. The creep effects significantly impact the biaxial stress distribution of reinforced concrete slabs. Existing creep analysis and computation methods for these structures have some limitations. Therefore, exploring an appropriate two-dimensional creep analysis approach

In this paper, a generalized self-consistent model of nanocoated fiber composite material considering interface effect is established by using the Gurtin-Murdoch surface/interface elasticity theory, elastic wave theory and micromechanics methods, and the propagation of anti-plane shear electroelastic wave in infinite nano-piezoelectric material is analyzed. Based on the wave function expansion method

Aircraft structures inevitably encounter complex situations, including material dispersion and uncertain flight conditions, during their service life. This paper focuses on the wing structure and presents a safety-factor-assisted non-probabilistic reliability-based topology optimization (SF-NRBTO) design method for uncertain optimization of wing structures. To begin, non-probabilistic uncertainty characterization

Ultimate bearing capacity is the main basis for evaluating the safety state of in-service reinforced concrete (RC) arch bridges. However, current evaluation methods require a lot of cost to handle the material nonlinearity problem, thereby failing to efficiently addressing such a tough issue. To this end, a novel method for calculating the ultimate bearing capacity of in-service RC arch bridges is

Investment in reducing emissions for many diverse companies is a practical strategy to achieve the emissions objectives as outlined by the United Nations Framework Convention on Climate Change. Livestock-producing farms often fall short of sustainability goals, even though many businesses have already adopted an investment strategy towards sustainability with success. Thereby, livestock-producing farms

Bacterial dynamics occurring in shared water environments during food processing are typically modeled assuming a homogeneous mixing profile. However, given the tank configurations, and water recirculation and reuse specifications used in many facilities, uniform mixing is not always applicable. Towards this goal, we here developed a novel reaction-diffusion-advection model that captures temporal and

Since that a single controller for intelligent vehicle path tracking is difficult to adapt to complex working conditions and achieve good system control performance, inspired by the concept of control redundancy, an adaptive weight based dual-steering control cooperative game coordinated optimization with fault-tolerant control method for intelligent vehicle path tracking is proposed in this paper

Tunnel portals are particularly vulnerable during seismic events due to the influence of adjacent slope geometry and fractured rock formations. This study evaluates the seismic response of tunnel portals and determines an appropriate fortification range. Ray theory is employed to calculate the displacement field of a single-sided slope subjected to incident SH waves, while the tunnel entrance is modeled

Energy harvesting technology is inevitably applied in complex excitation environments, such as railway infrastructure and aerospace. Therefore, it is necessary to explore the coupled multi-field effect on the energy harvester. This paper investigates coupled thermo-electric-elastic rotational piezoelectric energy harvesters, and the coupled multi-field equations are constructed and solved by Green's

Surface rupture in ferrofluid layers is a special case of the well-known Rosensweig instability, which can be triggered by applying a strong magnetic field. This study investigates the rupture dynamics in a ferrofluid interlayer sandwiched between two non-magnetic fluids, influenced by a non-homogenous vertical magnetic field. Simulations are performed using a generalized conservative phase-field lattice

To solve the instability problem in quadrotor control system subject to parametric uncertainties and external disturbances, an attitude control approach integrated with adaptive fuzzy gain-scheduling desired model compensation robust integral of the sign of the error is proposed. Firstly, the original cascade model of attitude motion is transformed into a strict feedback form with lumped disturbances

This work aims to optimize the multi-material structures subjected to self-weight loading for the first time. Ignoring the self-weight loads results in less reliable designs, and to enhance the strength of optimized designs, stress-constrained multi-material topology optimization (MMTO) is considered with body forces. Two stress constraint aggregation schemes are employed and comparable, such as the

An analytical one-dimensional model for the distribution of electric fields within multiple material layers is developed and analyzed. The model originates from the study of large three-phase electric smelting furnaces for ferroalloys and is derived from the low-frequency time-harmonic Maxwell's equations. A solution is obtained for a general case with N layers of material with different electromagnetic

Previous stress solutions for cold region tunnels (CRT) are basically based on the assumption of full bond contact between the lining and surrounding rock (SR). Whereas, in actual engineering practices, the lining and SR are in frictional contact condition. Based on the complex variable function theory and optimization method, the stress solution of CRT is established under the frictional contact condition

The fractal dimension logistic curve model offers a promising approach to understanding the dynamic patterns of urban development. By deriving formulas for growth rate and acceleration of fractal dimension, we can pinpoint the inflection points in urban growth and delineate distinct stages of development. Previous studies have focused on analyzing fractal dimension values over long time spans, which

Variational integration approaches are favorable for long-time simulations, due to their remarkable symplectic and momentum conservation properties, as well as the nearly energy-preserving feature with the bounded energy error. However, none of the work has been introduced into arbitrary Lagrangian-Eulerian (ALE) formulations, which are crucial to applications such as the deployment of tether satellites

Neural radiance fields (NeRFs) are a deep learning technique that generates novel views of 3D scenes from multi-view images. As an extension of NeRFs, SeaThru-NeRF mitigates the effects of scattering media on the structural appearance and geometric information. However, like most deep learning models, SeaThru-NeRF has inherent uncertainty in its predictions and produces artifacts in the rendering results

It is difficult to analytically solve the contact problem of one-dimensional hexagonal quasicrystal (1DHQ) coating considering the coupling effects of adhesion, friction force and frictional heat in the contact region, especially considering both the frictional heat and adhesion simultaneously. The thermally frictional adhesive contact problem of 1DHQ coating is investigated using a discrete convolution-fast

For a suspension bridge with a spatial cable system, the 3D curved main cable undergoes large lateral and torsional deformations during construction, which increases the difficulty of construction control. If using the traditional ideal flexible cable assumption, the torsional deformation cannot be analyzed. Therefore, incorporating the main cable's torsional and flexural stiffnesses in shape-finding

The motion and deformation laws of multi object interactions in computational models depend on contact algorithms. However, research on the peridynamic contact problem is limited. In this paper, in order to effectively prevent non-physical intrusion during contact, the inherent problems of the contact algorithm in peridynamic discrete models are analyzed, and a force boundary contact method using nonlinear

We introduce novel epidemic models with single and two strains described by systems of delay differential equations with a periodic time-dependent disease transmission rate, and based on the number of newly infected individuals. Transitions between infected, recovered, and returning to susceptible compartments due to waning immunity are determined by the accompanying time delays. Positiveness, existence

The study presents a novel approach for stochastic nonlinear model updating in structural dynamics, employing a Bayesian framework integrated with Markov Chain Monte Carlo (MCMC) sampling for parameter estimation by using an approximated likelihood function. The proposed methodology is applied to both numerical and experimental cases. The paper commences by introducing Bayesian inference and its constituents:

Classical couple stress theory is indeterminate since the number of independent basic equations is inconsistent with that of field variables and the corresponding differential equation is not closed. The purpose of this paper is to remedy this gap and it is proven that the spherical part of the couple stress tensor vanishes when neglecting torsional deformation. With the vanishing trace of the couple

Analytical investigations to characterize the effective mechanical properties of lattice materials allow an in-depth exploration of the parameter space efficiently following an insightful, yet elegant framework. 2D lattice materials, which have been extensively dealt with in the literature following analytical as well as numerical and experimental approaches, have limitations concerning multi-directional

Depending on processing technologies and working conditions, imperfect bonding at the layer-substrate interface may occur, resulting in diverse mechanical responses compared to a perfectly bonded layer-substrate system. This study focuses on an imperfect interface under force-like conditions and incorporates it into a nanoscale adhesive contact model to explore the influences of interfacial imperfection

This paper aims to improve the flexural stability of rotating pipes conveying fluid by introducing a smart piezoelectric feedback structure. The pipe is laminated along the radial direction, and a steady fluid flows inside the pipe. In the meantime, the pipe rotates around a vertical axis at one end. A pair of piezoelectric sensor and actuator connected with a feedback gain circuit are designed to

Aiming at the high computational costs of the current multi-source X-ray radiation numerical simulations, a multi-source X-ray evaluation method based on a synergistic effect model is studied. First, based on the advantage of the low computational cost of single-source X-ray radiation numerical simulations, a hierarchical Gaussian process model is used to construct a superimposed single-source numerical

In hygrothermal environments, the coupling effects of temperature and moisture substantially impact deflection and stresses play a significant role. This study presents a coupled hygrothermoelastic model with non-Fourier and non-Fick effects established by introducing relaxation times or phase lags of heat and moisture flux accompanied by memory-dependent derivatives. The boundary value problem is

In the study of dynamic balancing for flexible rotors operating at high speeds, determining the unbalanced position of the rotor has consistently posed significant challenges. Accurate identification of the unbalanced position enables low-speed dynamic balancing to serve as a viable alternative to high-speed methods, ultimately reducing costs and enhancing operational efficiency. Although deep learning

Intelligent controllers based on the broad learning system can simplify the process of model parameter adjustment, finding wide applications in the motion control of multi-joint robotic arms. However, motion controllers for multi-joint robotic arms based on broad learning system exhibit insufficient precision and overlook the impact of joint motion commonalities on controller design. Therefore, this