Dynamic Loading Research Articles

Anti-Slip Control System with Self-Oscillation Suppression Function for the Electromechanical Drive of Wheeled Vehicles

The movement of a wheeled vehicle is a non-regular dynamic process characterized by a large number of states that depend on the movement conditions. This movement involves a large number of situations where elastic tires skid and slip against the base surface. This reduces the efficiency of movement as useful mechanical energy of the electromechanical drive is spent to overcome the increased skidding and slipping. Complete sliding results in the loss of control over the vehicle, which is unsafe. Processes that take place immediately before such phenomena are of special interest as their parameters can be useful in diagnostics and control. Additionally, such situations involve adverse oscillatory processes that cause additional dynamic mechanical and electrical loading in the electromechanical drive that can result in its failure. The authors provide the results of laboratory road research into the emergence of self-oscillatory phenomena during the rolling of a wheel with increased skidding on the base surface and a low traction factor. This paper reviews the methods of designing an anti-slip control system for wheels with an oscillation damping function and studies the applicability and efficiency of the suggested method using mathematical simulation of the virtual vehicle operation in the Matlab Simulink software package. Using the self-oscillation suppression algorithm in the control system helps reduce the maximum amplitude values by 5 times and average amplitudes by 2.5 times while preventing the moment operator from changing. The maximum values of current oscillation amplitude during algorithm changes were reduced by 2.5 times, while the current change rate was reduced by 3 times. The reduction in the current-change amplitude and rate proves the efficiency of the self-oscillation suppression algorithm. The high change rate of the current consumed by the drive’s inverters may have a negative impact on the remaining operating life of the rechargeable electric power storage system. This impact increases with the proximity of its location due to the low inductance of the connecting lines and the operating parameters, and the useful life of the components of the autonomous voltage inverters.

Vibration Control of AFG Beam with Moving Load in Thermal Environment

Forced vibrations resulting from moving loads, along with efficient vibration control, are essential in transportation engineering, earthquake engineering, and aerospace engineering. In this study, the vibrational response of an axially functionally graded (AFG) beam subjected to a moving harmonic load within a thermal environment was investigated. The primary aim was to explore the potential of controlling this vibration by incorporating a nonlinear energy sink (NES). A model for the AFG beam, with clamped–clamped boundary conditions, was developed using Euler–Bernoulli beam theory and the Lagrange method, accounting for the effects of the thermal environment and the moving load. The numerical simulations were performed using the Newmark method to solve the governing equations. The results demonstrated the effectiveness of the NES in mitigating the vibrational response of the beam under thermal and dynamic loading conditions. The effective reduction of maximum deflection caused by moving loads was set as the optimization objective to identify the most optimal parameters of the NES. The results were presented through a series of parameter analyses, revealing that the nonlinear damper can quickly dissipate the beam’s energy when the loads exit the structure. Furthermore, a properly designed NES can result in a 2.4-fold increase in suppression efficiency.

Nonlinear damping amplifier friction bearings

Abstract The paper introduces damping amplifiers integrated into the core material of conventional nonlinear friction base isolators to improve their vibration attenuation capabilities and mitigate their shortcomings. Four new types of damping amplifier friction bearings are introduced: levered, nested, compound, and damping. The H2 optimisation strategy is utilised to obtain the closed-form analytical solution for the optimised designed parameters. The analytical investigation confirms the efficiency of the recently obtained closed-form equations for the optimal design parameters. The frequency response function was used to develop closed-form formulas for the isolator and main structure's dynamic responses. The harmonic and random white-noise excitation served as the basis. Furthermore, numerical analysis by considering real earthquake load has confirmed the novel isolators' efficiency. The vibration reduction capacities of the H2 optimised damping amplifier friction bearings, compound damping amplifier friction bearings, nested damping amplifier friction bearings, and levered damping amplifier friction bearings are 76.1 % superior to the optimum conventional base isolator. These findings demonstrate how the proposed designs may improve structural resistance to dynamic loads.

The Reduction of Embodied Carbon in Steel Structures Through the Implementation of Control Systems

The rapid expansion of global infrastructure has amplified the environmental impact of construction, particularly through the carbon footprint of structures. Addressing this challenge, this study examined the potential of vibration control systems to reduce the carbon footprint of steel-frame buildings subject to dynamic wind loads. Utilizing the Force Analogy Method (FAM), which effectively addresses nonlinearity in structural analysis, the research modeled a 10-story steel frame subjected to synthetic downburst wind time history velocities generated through spectral simulation techniques. Both passive and active control systems were implemented, with a focus on tuned mass dampers (TMDs) and active mass dampers (AMDs) to reduce structural displacements and accelerations. The results revealed that these systems not only significantly reduce the peak structural responses but also, when combined with optimized manufacturing methods, lead to a decrease in steel usage. This optimization contributes to a reduction of up to 20% in CO2 emissions during the pre-use stage of a building’s lifecycle. By enhancing the material efficiency and minimizing the environmental impacts, this research highlights the critical role of advanced control systems, supported by new nonlinear analytical methods, in promoting environmentally conscious engineering. This approach aims to guide future generations in developing structural engineering projects that prioritize sustainable practices.

Assessment of the Usage of Innovative Integrated Photogrammetry Method in Structural Behaviour Analysis: The Case of Mardin Melik Mahmut Mosque

The integration of photogrammetric modeling with the finite element method has emerged as a valuable approach in the practical analysis and determination of structural behavior. Photogrammetry, a technique that utilizes the analysis and processing of photographs to create three-dimensional models of real-world objects, offers a powerful tool for capturing accurate geometric data. On the other hand, the finite element method provides a numerical framework for the mathematical modeling and analysis of complex structural systems. This article presents a methodology that integrates these two modeling techniques by comparing their performance with integrated and classical models. Classical modelling is a technique performed in a finite element software and has been applied for many years. Accordingly, this study aims to reveal the limitations of photogrammetry, develop solutions to these limitations, and provide integrated model generation. The material definitions and load assignments were kept consistent across both modeling techniques for observing the differences in analysis. The study used SAP2000 and modal analysis was conducted to analyse the behaviour and to compare the geometrical properties of the models independent of region and time. The obtained results reveal a high level of similarity, with the natural vibration periods of the models demonstrating 98%, the stress values exhibiting 90%, and deformation values 90% similarity a result of the dynamic loads applied in the X-Y direction. Consequently, this study highlights the potential for further improvement in the integrated model generation process by identifying the advantages and disadvantages of each modeling technique.

Fault Diagnosis of Wire Disconnection in Heater Control System Using One-Dimensional Convolutional Neural Network

Heaters are critical components in various heating control systems, and their faults are often a primary cause of system failure, drawing significant attention from engineers and researchers. Early and accurate fault diagnosis is crucial to prevent cascading failures. Many diagnostic methods target faults under generally stable and simple operating conditions, such as constant load or steady-state temperature. However, real-world scenarios are often complex and variable, involving dynamic loads, nonlinear temperature rises, and other challenges, which limit diagnostic accuracy. To address this issue, this paper proposes an intelligent fault diagnosis model based on a one-dimensional convolutional neural network (CNN), using the heater’s current and voltage as the input to the neural network. The effectiveness and accuracy of the proposed model were validated through experimental data under two different conditions, achieving an average accuracy rate of 98%. The disconnection faults were generated during actual operation and occurred in the early stages, differing significantly from artificially simulated faults, thereby increasing the difficulty of accurate diagnosis. Analysis and comparison of the experimental results demonstrate the feasibility of the intelligent diagnostic model and its high diagnostic accuracy.

Charpy Impact Test Result Comparison on Reinforcing Materials used in Continuous Filament 3D Printing

With the growing industrial demand for materials that can withstand dynamic loads, composite 3D printing, particularly utilizing continuous fiber reinforcements, presents a promising solution. This study investigates the toughness of three fiber-reinforced materials, namely carbon fiber, Kelvar, and fiberglass, by conducting Charpy impact tests. The results reveal that fiber-reinforced 3D materials significantly outperform standard 3D printed components, with fiberglass showing the highest toughness. These findings demonstrate that fiber-reinforced 3D printed materials offer a viable alternative for applications requiring high toughness and dynamic resistance.

Marshall Properties and Rutting Resistance for Asphaltic Mixtures Modified by Nano-Montmorillonite

Rutting is a significant problem in flexible asphalt pavements, causing permanent deformation. Increased traffic, axle load, tire pressure, and hot weather have recently accelerated rutting in flexible pavements. Several researchers have suggested using nanomaterials to improve asphalt pavement and prolong its lifespan. The nano clay chosen for this study is a natural, hydrophilic montmorillonite in its raw form. Consequently, incorporating Nano-montmorillonite (MMT) into asphalt mixtures to improve performance under dynamic loads has gained significant attention. This can help reduce rutting damage and ensure the safety and durability of road surfaces. This study examines the impact of incorporating MMT into hot mix asphalt on the Marshall properties and resistance to rutting. It involved determining the optimal asphalt content using the Marshall design method, as well as the rutting depth for asphalt mixes using wheel tracking tests, for mixtures comprising different MMT percentages (2%, 4%, and 6%) as a percentage of the asphalt binder. The optimal asphalt content was 4.93% for the control mix. The inclusion of 6% MMT increased the Marshall stability the most by 16.79%. Marshall flow decreased when MMT was added. The control mix had a Marshall flow of 3.30 mm, but when using 4% MMT, the flow decreased to 2.81 mm, the most significant reduction. The ideal proportion of MMT was 6%, resulting in a 39.79% reduction in rut depth compared to the control mixture.

Effect of fibre content on low-temperature failure strength and toughness of different sized BFRC under static and dynamic loadings: An experimental study

Effect of fibre content on low-temperature failure strength and toughness of different sized BFRC under static and dynamic loadings: An experimental study

A computational study on dynamic behavior of articular cartilage under cyclic compressive loading and magnetic field.

The dynamic behavior of articular cartilage (a soft porous biological tissue) with strain-dependent nonlinear permeability under cyclic compressive loading and magnetic field is investigated computationally. The compressive force is applied on top surface of the cylindrical plug of the tissue by means of a porous filter. The study of mechanical and deformational behavior of soft porous tissues such as articular cartilage under dynamic compressive loading and magnetic field is useful in understanding the underlying mechano-biological process that may lead to the development of a treatment and recovery protocol in a diseased state. In the present study, a linear biphasic mixture theory of porous media has been employed to derive the governing equations in terms of solid displacement and interstitial fluid pressure in the tissue. Exact solutions for the solid displacement, fluid pressure, and relative fluid velocity are provided for the constant permeability case which have also been used to validate the numerical method. On the other hand, the full nonlinear problem has been solved numerically using the method of lines and the outcomes are presented graphically to assess the effects of various emerging parameters. The results indicate that there is an increase in the solid dilatation due to application of magnetic field and this effect is more prominent at relatively high loading frequencies. In general, a repeated compressive force has generated an oscillating positive-negative hydrostatic pressure within the tissue, however, a strong magnetic field at comparatively high loading frequency enforces the tissue to have only the positive (supra-ambient) pressure. The outcomes have also revealed that the pattern of the dynamic behavior of the tissue is strongly dependent on the loading frequency. A considerable phase shift in the dilatation and fluid pressure has been noticed due to the loading frequency as well as magnetic effects. It has also been found that the permeability parameter has a minimal impact on the solid deformation and fluid pressure in all scenarios with a very small phase shift.

Impact of HWD dynamic loading on measured deflection basins and back-calculated stiffnesses of flexible airport pavements

Accurate measurement of pavement structural response is critical when evaluating the condition and load-bearing capacity of a flexible airport pavement. Pavement surface deflection basins tested by Heavy Weight Deflectometer (HWD) have been widely applied as a non-destructive testing method to analyse the elastic modulus of pavement layers via a back-calculation procedure. A clear linear relationship between measured deflections and HWD drop loads was established, with R2>0.99. The studied flexible pavement structure showed linear elastic responses under different drop loads, with relatively stable elastic moduli of pavement layers. With the increasing drop load (DL), the back-calculated hot-mix asphalt (HMA) surface modulus was slightly influenced. The results also identified the existing buried sensors may affect the measured HWD responses. By analysing statistical results, this study provides a benchmark for airport owners to evaluate the structural conditions for their flexible pavements when applying HWD in their maintenance and rehabilitation (M&R) works.

Computation of Viscoelastic Shear Shock Waves Using Finite Volume Schemes With Artificial Compressibility.

The formation of shear shock waves in the brain has been proposed as one of the plausible explanations for deep intracranial injuries. In fact, such singular solutions emerge naturally in soft viscoelastic tissues under dynamic loading conditions. To improve our understanding of the mechanical processes at hand, the development of dedicated computational models is needed. The present study concerns three-dimensional numerical models of incompressible viscoelastic solids whose motion is analysed by means of shock-capturing finite volume methods. More specifically, we focus on the use of the artificial compressibility method, a technique that has been frequently employed in computational fluid dynamics. The material behaviour is deduced from the Fung-Simo quasi-linear viscoelasiticity (QLV) theory where the elastic response is of Yeoh type. We analyse the accuracy of the method and demonstrate its applicability for the study of nonlinear wave propagation in soft solids. The numerical results cover accuracy tests, shock formation and wave focusing.

Study on the mechanism and control of strong ground pressure in the mining of shallow buried close-distance coal seam passing through the loess hilly region

Shallow buried close-distance coal seam (SBCCS) is widely found in northern Shaanxi, China. In the process of mining under the loess hilly area (LHA) in SBCCS, many accidents of strong ground pressure have occurred. Taking the in the Zhangjiamao Coal Mine as the background, this study revealed the mechanism of high ground pressure when the working face of lower coal seam passes through the surface loess hilly region. On-site measurements, physical similarity simulation, numerical calculation, and theoretical analysis were combined to study the mining process of SBCCS. The movement characteristics of the activated structure of the interval strata of the lower coal seam were analyzed. The dynamic load and the change pattern of the front abutment pressure (FAP) of the support during the loading stage of entering and exiting the loess hilly were determined. A coupled structural mechanics model of the overlying activated voussoir beam and the step voussoir beam rock beam of the interval strata was established, revealing the dynamic loading mechanism of strong ground pressure during passing through the LHA. The results showed that the dynamic load of the working face was the highest in areas affected by the load of the LHA, followed by the load while entering the LHA, the peak value of the FAP in the load-influenced LHA was high, which was approximately 1.12 times that after leaving the load-influenced LHA and 1.61 times that before entering this area. By establishing a mechanical model of the roof coupling structure when entering and exiting the load-influenced LHA, it was revealed that the dynamic load of the support while mining under the goaf in the LHA is mainly due to the synchronous movement of the activated structure of the collapsed roof of the upper coal seam and the interval rock structure. The load in the LHA was transmitted to the interval rock structure through the activated structure, resulting in a high dynamic load on the support. The study concluded that the determination of the support resistance of the working face should be based on the high-period compressive load of the synchronous movement of the roof structure in the LHA. Through the engineering practice of hydraulic fracturing, the roof structure of the interval strata is changed, which can effectively reduce the dynamic pressure disaster of the working face. The research provides a scientific basis for the safe and efficient mining of shallow coalfields, and it provides reference for similar mining.

Engineered ionic polymer metal composites (eIPMCs) under dynamic compression loading conditions: theory and experiments

Abstract Engineered Ionic Polymer Metal Composites (eIPMCs) represent the next generation of IPMCs, soft electro-chemo-mechanically coupled smart materials used as actuators and sensors. Recent studies indicate that eIPMC sensors, featuring unique microstructures at the interface between the ionic polymer membrane and the electrode, exhibit enhanced electrochemical behavior and sensitivity under compression, as compared to traditional IPMCs. However, a complete and experimentally-validated model of how eIPMCs behave under dynamic compression loads is currently missing. In this paper, we develop an analytical model for eIPMC sensors, elucidating the role of the engineered interface, modeled as a separate material layer with unique mechanical and electrochemical properties. Theoretical predictions focus on the mechanical-to-electrochemical transduction response under dynamic compressive loads. Experimental verification is conducted on conventional IPMC and novel eIPMC samples fabricated using the polymer abrading technique. Electrochemical impedance spectroscopy is performed to study the effect of the engineered interface on the electrochemical properties. Open-circuit voltage and short-circuit current are measured under external compressive loads in different loading scenarios to demonstrate sensing performance. Results show good qualitative agreement between experimental trends and model predictions. Experiments over the frequency range 1-18 Hz demonstrate an increase of 220-290% in open-circuit voltage and 17-166% in short-circuit current sensitivity for eIPMCs over IPMCs.

Impact energy release characteristics and penetration behavior of high-density VNbTa medium-entropy alloys

This study systematically investigated the dynamic mechanical properties and penetration-damage behavior of high-density VNbTa medium-entropy alloys under dynamic loading. The split Hopkinson bar, impact energy release, and spaced-target plate tests were carried out. Results from the impact energy release test indicated that a significant chemical reaction and substantial energy release occurred when the alloy hit a rigid target plate at high speed. The spaced-target plate penetration test verified the combined destructive effect of the alloy’s kinetic and chemical energies during penetration, leading to large perforations and severe deformation of the rear target plate. Moreover, a shock-induced energy release model and a fragment cloud diffusion model were established, uncovering the energy release mechanism and fragment-cloud expansion law. These findings provide a theoretical and experimental basis for the design and application of high-density, high-energy structural materials.

Acoustic calculation of process pipelines of a compressor station for assessing low-frequency pressure pulsations in dead-end branches

Relevance. The gas industry cannot be imagined without main gas pipelines, which are necessary to provide suppliers with the declared quantities of gas. To fulfill contractual obligations, compressor stations with high-flow compressor units are used. In order to ensure reliable operation and avoid premature failure of process equipment, periodic diagnostic work is carried out. Such measures allow increasing the service life of objects, but due to high static stresses and the occurrence of intense dynamic loads characteristic of process pipelines, this is not a sufficient condition for identifying potentially dangerous areas. In this regard, recently, engineering tools for calculating dynamic processes have been increasingly used to help solve such complex problems in order to study these processes in real systems and operating modes. Methods. Engineering analysis products to calculate the amplification of acoustic vibrations in dead-end branches of the technological piping of a compressor station. Results and conclusions. The authors have calculated the technological piping to assess the acoustic vibrations, the natural frequencies of vibrations of dead-end clarifications and the critical speeds, at which these vibrations occur. The paper introduces the results of the acoustic calculation carried out in the ANSYS Workbench software. According to these results the authors determined the pulsation amplifications in the dead-end branches, which are relatively large and can be the cause of high low-frequency vibrations.

Energy absorption characteristics of corrugated grooves thin-walled structure inspired by nautilus shell biological geometry

Abstract Crash box is a vital component for a vehicle in absorbing kinetic energy in the event of a road collision. The thin-walled structure is emerging as a favorable geometry in designing the crash box. This article investigates the energy absorption performance of the corrugated nautilus shell bio-inspired thin-walled structure made of AA6061-T6 aluminum alloy. This structure’s performance was evaluated using finite element analysis (FEA) under quasi-static and dynamic loading conditions in an axial direction, then validated by a quasi-static compression experimental test, which showed satisfactory agreement. The results show that the corrugated nautilus shell bio-inspired thin-walled structure integrated with corrugated grooves reduced peak crushing force (PCF) by 17.9% and increased specific energy absorption (SEA) by 1.3% and crush force efficiency (CFE) by 17.6% compared to non-corrugated design. It can be concluded that the proposed nautilus shell bio-inspired thin-walled structure integrated with corrugated grooves has the potential to replace conventional hollow square designs in vehicle crash box applications.

Highly deformable flapping membrane wings suppress the leading edge vortex in hover to perform better

Airborne insects generate a leading edge vortex when they flap their wings. This coherent vortex is a low-pressure region that enhances the lift of flapping wings compared to fixed wings. Insect wings are thin membranes strengthened by a system of veins that does not allow large wing deformations. Bat wings are thin compliant skin membranes stretched between their limbs, hand, and body that show larger deformations during flapping wing flight. This study examines the role of the leading edge vortex on highly deformable membrane wings that passively change shape under fluid dynamic loading maintaining a positive camber throughout the hover cycle. Our experiments reveal that unsteady wing deformations suppress the formation of a coherent leading edge vortex as flexibility increases. At lift and energy optimal aeroelastic conditions, there is no more leading edge vortex. Instead, vorticity accumulates in a bound shear layer covering the wing's upper surface from the leading to the trailing edge. Despite the absence of a leading edge vortex, the optimal deformable membrane wings demonstrate enhanced lift and energy efficiency compared to their rigid counterparts. It is possible that small bats rely on this mechanism for efficient hovering. We relate the force production on the wings with their deformation through scaling analyses. Additionally, we identify the geometric angles at the leading and trailing edges as observable indicators of the flow state and use them to map out the transitions of the flow topology and their aerodynamic performance for a wide range of aeroelastic conditions.

Structural and Modal Analysis of a Small Wind Turbine Blade Considering Composite Material and the IEC 61400-2 Standard

IEC 61400-2 establishes the Simplified Load Method for designing low-power wind turbine blades without considering dynamic loads in the simplified load methodology. This paper analyzes the load hypotheses established by the standard, also considering the natural frequencies in a 900 W blade. The research methodology begins with the design parameters, the application of the BEM Method, and the use of the QBlade software. Then, the load hypotheses of the standard are defined. Finally, the structural design and the modal and structural analysis of the blade were conducted using FEM-based software. The results show that the minimum participation factors are found on the z-axis and the maximum on the x- and y-axis, and their magnitudes decrease when the natural frequency increases. In general, the principal maximum stresses are located in the middle section of the blade, in the external fiberglass layer, both on the intrados and extrados sides. In conclusion, structural scenarios were established to relate the participation factors of the modal analyses with the load hypotheses. The critical scenarios are at natural frequencies below 280 Hz.

Optimizing Distribution Transformer Ratings in the Presence of Electric Vehicle Charging and Renewable Energy Integration

Aims and Background: A re-evaluation of distribution transformer ratings is necessary to ensure efficient and reliable operation due to the significant impact of the growing number of electric vehicles (EVs) on load dynamics. The objective of this study is to optimize the rating of the distribution transformers to accommodate the year-round demand for electric vehicle charging while minimizing expenses and no-load losses. The performance and lifespan of transformers under dynamic hourly loads are evaluated by analysing real-world EV charging data, load profiles, and transformer parameters. Using state-of-the-art simulation, real-world data analysis, and optimization algorithms, this study optimizes the transformer distribution ratings under the integration of EV charging and renewable energy. Objectives and Methodology: Dynamic hourly load changes can be captured by analysing realworld electric vehicle charging data in conjunction with seasonal load profiles. In order to maximise transformer lifetime and minimise losses, convex optimisation is subjected to Karush-Kuhn- Tucker (KKT) conditions. Transformer performance is also assessed by using energy storage devices and solar energy simulations. To determine the impact of various electric vehicle charging scenarios on thermal stress and transformer ageing, sensitivity analyses are performed. Results and Discussion: Transformers with a 10% higher rating can manage maximum electric vehicle charging loads with a 15% slower loss of life acceleration, according to our models. Transformer performance is further optimised with the integration of solar energy and energy storage systems, which improves load control and reduces operational costs by up to 20%. Conclusion: Using a convex optimisation framework and the Karush-Kuhn-Tucker (KKT) criteria, the study achieves a 95% accuracy rate in predicting hourly load fluctuations.