Shock Absorber System Research Articles

Dynamic study through numerical simulations of MacPherson suspension and static analysis of shock absorber components

A suspension or shock absorber system is a mechanical device that is designed to attenuate or reduce the shock impulse and kinetic energy due to level differences or obstacles encountered by the car. In a vehicle structure, the shock absorber reduces the effect of driving on rough terrain, which automatically leads to improved driving quality and also increases passenger comfort.The purpose of this dynamic study by numerical simulations of the MacPherson strut suspension is to highlight the dynamic differences between the stock and heavy MacPherson suspension duty for the Volkswagen Jetta, because it is the most common type of suspension on vehicles, and it is not complex in terms of operation.The study was carried out only at the simulation stage in the MSC ADAMS program, for the dynamic analysis of the component parts, later the second phase of the research will propose the study on a real system.One of the specific objectives of the paper is to compare the two types of springs, the stock with which the car is equipped at the factory and the modified one, the heavy duty variant (package heavy roads).The second specific objective is to compare the two types of springs in relation to the two heights of the speed limiter and the two types of tires.The third objective of this paper is to perform a comparative analysis of the main components of a shock absorber assembly, statically through tests in the ABAQUS simulation program.Later, the results obtained after the analyzes indicated that the heavy duty type suspension has a higher degree of force attenuation. The end of the study was focused on the finite element analysis of the main components of a shock absorber in a suspension, analyzed from a static point of view.

An Innovative Energy Harvesting Shock Absorber System for Motorbikes

This article presents an innovative energy recovery shock absorber system for motorcycles. The shock absorber is named synchronous pulley - energy harvesting shock absorber (SP-EHSA). The SP-EHSA is the first system specifically designed to maximize the energy recovery of motorcycles without compromising their dynamic behavior. Throughout the article, the theoretical design, computer modeling, optimization, design, and testing of the system are presented. The article results in a validated computer model of the SP-EHSA shock absorber. The validation is done by manufacturing and testing a physical prototype on a test bench. A study of the energy recovery potential for different road profiles at speeds between 20 and 100 km/h was carried out, obtaining in a typical type B road at 60 km/h an estimated 19.68 W average power. Finally, the effect of energy management (i.e., battery's state of charge) on the dynamic behavior of the vehicle is analyzed.

Optimal Sacrificial Domains in Mechanical Polyproteins: S. epidermidis Adhesins Are Tuned for Work Dissipation.

The opportunistic pathogen Staphylococcus epidermidis utilizes a multidomain surface adhesin protein to bind host components and adhere to tissues. While it is known that the interaction between the SdrG receptor and its fibrinopeptide target (FgB) is exceptionally mechanostable (∼2 nN), the influence of downstream B domains (B1 and B2) is unclear. Here, we studied the mechanical relationships between folded B domains and the SdrG receptor bound to FgB. We used protein engineering, single-molecule force spectroscopy (SMFS) with an atomic force microscope (AFM), and Monte Carlo simulations to understand how the mechanical properties of folded sacrificial domains, in general, can be optimally tuned to match the stability of a receptor–ligand complex. Analogous to macroscopic suspension systems, sacrificial shock absorber domains should neither be too weak nor too strong to optimally dissipate mechanical energy. We built artificial molecular shock absorber systems based on the nanobody (VHH) scaffold and studied the competition between domain unfolding and receptor unbinding. We quantitatively determined the optimal stability of shock absorbers that maximizes work dissipation on average for a given receptor and found that natural sacrificial domains from pathogenic S. epidermidis and Clostridium perfringens adhesins exhibit stabilities at or near this optimum within a specific range of loading rates. These findings demonstrate how tuning the stability of sacrificial domains in adhesive polyproteins can be used to maximize mechanical work dissipation and serve as an adhesion strategy by bacteria.

The Design of a Structural Hyper-Resisting Element for Life-Threatening Earthquake Risk (SHELTER) for Building Collapse Scenarios: The Safety Chairs

Project SHELTER, Structural Hyper-resisting Element for Life-Threatening Earthquake Risk, aims at developing a strong and stiff functional unit to protect its occupants in case of severe earthquakes that lead to structural collapse. In case of collapse, these units will suffer impacts, particularly if they are installed in upper floors. To avoid severe injuries or death of occupants caused by collapse, safety chairs were designed, provided with shock-absorber systems and auxiliary retaining devices, to keep the occupants properly seated and safe. Three downfall scenarios were evaluated, consisting of vertical and tilted positions. A comprehensive numerical model to represent the human body was developed, mainly focused on chest behaviour and considering the anatomic limits of the vertebral spine. The mechanical ability of the safety chair to ensure the occupants’ safety was evaluated under these harsh conditions. Experimental downfall-and-impact tests will later be performed on shelter units, with crash-test dummies seated on the safety chairs for final validation.

Shock absorber system dynamic model in model-based environment

Shock absorber system dynamic model in model-based environment

Experimental Characterisation and FEA Comparison between Wave and Helical Springs

Vibrations are unwanted mechanical phenomena which cause performance deterioration of dedicated equipment and critical electronic hardware. In order to reduce this vibration during the transportation of the dedicated payloads, that is, optical payload or microwave payload and critical electronic hardware such as atomic clocks, detectors and containers with vibration isolation devices are used. Traditional vibration or shock absorbing systems are big in size which makes the whole container huge and bulky. In our present paper, we try to characterise different types of springs (helical and wave) and develop a FEM methodology to calculate the stress and displacement of the springs under load. Generally, helical springs are used with shock absorber systems having large displacement area. Instead of helical springs, we have proposed wave springs. In this study we have selected helical and wave springs for our experiments and compared them for the fulfilment of our objective. The future aim of this study is to select a suitable spring which can be used with a small size damper in order to make a compact vibration isolation system which will provide the same load carrying capacity in a constrained space as that of a traditional system. The CAD files of both the springs are modelled using Autodesk Inventor Professional 2019 and Creo Parametric 5.0, while FEM methodology is performed using HyperWorks 2019 for both the springs. The theoretical calculations of the models are compared with the FEA results and then validated experimentally.

The design of a structural Hyper-resisting element for Life Threatening Earthquake risk (SHELTER) for building collapse scenarios: The life-saving capsule

The most severe seismic events normally cause the collapse of vulnerable buildings’ leading to injuries and death of their occupants. Such catastrophic toll in death and injuries can be avoided based on an innovative approach currently underway, through the project SHELTER – Structural Hyper-resisting Element for Life Threatening Earthquake Risk (Ferreira et al., 2021), consisting on the development of a functional unit to protect the building occupants. Previous research found no relevant information about the ability of such kind of a structure to withstand the severity of building collapsing effects, while keeping the people inside it alive.The current work shows that there are chances of survival for those who occupy this shelter, as long as they settle over chairs equipped with a shock-absorber. The shelter will fall following the building collapse and will suffer several impacts with it, the most hazardous to be the last one, when it hits the ground. This shock-absorber system was designed so it could retrieve humanly tolerable accelerations, for different impact conditions, meaning different ground stiffness’s and different impact positions. Two different criteria were used, one based in human tolerance curves (Eiband’s curves) and another based directly on the compressive strength of the human spine.The shelter structural behaviour was also validated, through nonlinear time-history analyses of complete shelter models, for either the shelter fall from height, i.e., the building collapse when the shelter is installed in an upper floor, and for the building collapse when the shelter is installed on the ground floor and receives all the building rubble over it.

Optimal Modeling of an Elevator Chassis under Crash Scenario Based on Characterization and Validation of the Hyperelastic Material of Its Shock Absorber System

A wide variety of hyperelastic rubber-like materials, exhibiting strong nonlinear stress–strain relations under large deformations, is applied in various industrial mechanical systems and engineering applications involving shock and vibration absorbers. An optimal design procedure of an elevator chassis crashing on a hyperelastic shock absorber in a fail scenario, applicable in large-scale mechanical systems or industrial structures of high importance under strong nonlinear dynamic excitation, is presented in this work. For the characterization of the hyperelastic absorber, a Mooney–Rivlin material model was adopted, and a series of in-lab compression quasi-static tests were conducted. Applying a fully parallelizable state-of-the-art stochastic model updating methodology, coupled with robust, accurate and efficient Finite Element Analysis (FEA) software, the hyperelastic behavior of the shock absorber was validated under uniaxial large deformation, in order to tune all material parameters and develop a high-fidelity FE model of the shock absorber system. Next, a series of in situ full-scale experimental trials were carried out using a test-case elevator chassis, representing the crash scenario on the buffer absorber system, after a controlled free fall. A limited number of sensors, i.e., triaxial accelerometers and strain gauges, were placed at characteristic points of the real structure of the elevator chassis recording experimental data. A discrete Finite Element (FE) model of the experimentally tested arrangement involving the elevator chassis and updated buffer absorber system along with all boundary conditions was developed and used in explicit nonlinear analysis of the crash scenario. Steel material properties and the characterized updated Mooney–Rivlin material model were assigned to the elevator chassis and buffer, respectively. A direct comparison of the numerical and experimental data validated the reliability and accuracy of the methodology applied, whereas results of the analysis were used in order to redesign and optimize a new-design elevator chassis, achieving minimum design stresses and satisfying serviceability limit states.

Modeling and simulation of energy harvesting hydraulically interconnected shock absorber

Ride comfort, road handling and fuel efficiency of a vehicle have always been crucial factors during vehicle shock absorber design. This paper proposes and studies a novel energy harvesting hydraulically interconnected shock absorber (EH-HISA) system to improve energy harvesting and ride comfort. A comparison study is done for the dynamic responses and power harvested by the vehicle equipped with EH-HISA and previous design for energy-harvesting hydraulically interconnected suspension (EH-HIS). In addition, the EH-HISA consists of two energy harvesting units compared to four energy harvesting units in EH-HIS, thus reducing the cost and weight of the overall system. A full car model is set up in AMESim to simulate the vehicle over a C class road. The comparison indicates that EH-HISA shows 11% reduction in lateral acceleration of car body center of gravity, during double lane change test over EH-HIS. While the peak roll angle of the vehicle body shows almost similar results of 1.4 degrees for EH-HISA and 1.2 degrees for EH-HIS. The average energy harvested for EH-HISA reaches a maximum value of 230 W and shows an improvement of 222 % over EH-HIS for the same road conditions and vehicle parameters.

Энергетические показатели электромагнитного гасителя колебаний транспортного средства

The creation of an electromagnetic shock absorber system is necessary taking into account such parameters of the vehicle and operating conditions as the quality of the roadway, the grades, and the weight and size of the vehicle. A mathematical simulation model of the vehicle was developed to determine energy indicators in various road sections. The MATLAB Simulink programming environment was chosen to create the most practical and functional simulation model. A number of experiments were carried out using various parameters of the vehicle, types of roadways and driving cycles. Simulation results allow obtaining basic characteristics of electromagnetic damper of the selected vehicle, on the basis of which a linear electromagnetic damper shock absorber will be calculated. System energy efficiency was determined when using a vehicle on roads having a different road surface evenness index.

A Computational Study of Liquid Shock Absorption for Prevention of Traumatic Brain Injury.

Mild traumatic brain injury (mTBI), more colloquially known as concussion, is common in contact sports such as American football, leading to increased scrutiny of head protective gear. Standardized laboratory impact testing, such as the yearly National Football League (NFL) helmet test, is used to rank the protective performance of football helmets, motivating new technologies to improve the safety of helmets relative to existing equipment. In this work, we hypothesized that a helmet which transmits a nearly constant minimum force will result in a reduced risk of mTBI. To evaluate the plausibility of this hypothesis, we first show that the optimal force transmitted to the head, in a reduced order model of the brain, is in fact a constant force profile. To simulate the effects of a constant force within a helmet, we conceptualize a fluid-based shock absorber system for use within a football helmet. We integrate this system within a computational helmet model and simulate its performance on the standard NFL helmet test impact conditions. The simulated helmet is compared with other helmet designs with different technologies. Computer simulations of head impacts with liquid shock absorption predict that, at the highest impact speed (9.3 m/s), the average brain tissue strain is reduced by 27.6% ± 9.3 compared to existing helmet padding when tested on the NFL helmet protocol. This simulation-based study puts forth a target benchmark for the future design of physical manifestations of this technology.

Methodology for Comprehensive Comparison of Energy Harvesting Shock Absorber Systems

In recent years, there has been a lot of work related to Energy Harvesting Shock Absorbers (EHSA). These devices harvest energy from the movement of the vehicle’s shock absorbers caused by road roughness, braking, acceleration and turning. There are different technologies that can be used in these systems, but it is not clear which would be the best option if you want to replace a conventional shock absorber with an EHSA. This article presents a methodology to compare the performance of different EHSA technologies that can replace a shock absorber with a given damping coefficient. The methodology allows to include different analysis options, including different types of driving cycles, computer vehicle models, input signals and road types. The article tests the methodology in selecting the optimal EHSA technology for a particular shock absorber and vehicle, optimizing at the same time energy recovery. In addition, a study of parameters in each type of technology is included to analyze its influence on the final objective. In the example analyzed, the EHSA technology with a rack and pinion system turned out to be the best. The proposed methodology can be extrapolated to other case studies and design objectives.

Multi-physics based Simulations of an Oleo-pneumatic Shock Absorber System for PHM

The paper presents multi-physics (Mechanical, Thermal, Hydraulic, and Pneumatic) based modelling and simulation of an Oleo-pneumatic shock absorber with fault capabilities. The fault simulated in this model is leakage due to eccentricity. The one-dimensional shock absorber system models to give loads at different sink velocities. These load values, used in the structural model to do static stress analysis. By using these loads directly from the system model eliminates the error in load computation from the load’s group, thereby eliminating the time and cost involved in this activity. The models and static stress analyses carried out with both 1-D and 3-D elements. The 3-D landing gear model meshed with using both auto and manual mesh generation options. The consequences of both 1-D and 3-D models mesh generation, discussed in this paper. The static stress analysis, compared with the experimental results and it is found that the results are within 5% deviation. Based on the static stress and fatigue analysis computed the life of a landing gear.

Stability Control Investigation of a Self-Balancing Platform on the Robot Smart Car Using Navigation Parameters

A self-balancing platform is constructed on a robot smart car, and its navigation parameters are investigated by running the car outdoors on a straight surface with structured bumps of 3and 5 mm in height. A ball-and-socket joint are supported at the centre of the platform, which is to be freely rotated with the lateral and longitudinal movement of the platform and in each axis, is controlled by three servomotors. Which move according to the recorded data movements from a gyro-accelerometer sensor which controlled by an Arduino UNO. The SimMechanics Matlab simulation helps to give the initial values of all parameters and the additional unexpected signals due to the influence of bumps on the vibration signals, with the proportional-integral-derivative (PID) controller, used to control the relationship of the rapid simulation of the robot smart car and mathematical model between platform and car shock absorber system with respect to the servomotor’s rotation angle. These bump is more effective on the pitch and roll angle values when compared to other parameters, with more than 815 degrees and error up to 35 degrees due to vibration signals, and the time required for stabilization increases due to the bump height and the navigation parameters, roll angle from 2 to 6 in mean change value 2, yaw angle from 43 to 59 in mean change value 8 and pitch angle from 1 to 2 in mean change value 0.5, which indicates that yaw, roll and pitch angle have variation changing in Mission Planner software

A novel design of a damping failure free energy-harvesting shock absorber system

Abstract An energy-harvesting shock absorber can adjust the damping coefficient in real time to meet the vibration reduction, and it can also harvest energy from the vibration of a suspension. This paper proposed a novel design for an energy-harvesting shock absorber system. The study focusses mainly on the realization of energy harvest and damping control. A closed loop damping control strategy is proposed, with which, the shock absorber is not only able to supply a controllable electromagnetic damping force but can also harvest energy from the vibration. The system construction and working principle is introduced, and the experiment platforms are established. A series of simulations and experiments were conducted to demonstrate the effectiveness of the proposed shock absorber system. The results show that an average energy recovery efficiency of 40.72%–70.55% can be obtained when tested under sinusoidal excitation and random road excitation. The proposed system is characterized by a high response speed of 4 Hz, and it can meet the operating requirements under random road excitation. The results also indicate that the damping coefficient can be adjusted with a high precision of 93.56%, and thus, both the damping failure and damping fluctuation are effectively eliminated.

FSI simulation and experimental validation of nonlinear dynamic characteristics of a gas-pressurized hydraulic shock absorber

The structure, fluid and gas dynamic models of a gas-pressured hydraulic shock absorber are established to form a 3-D FSI (Fluid-Structure Interaction) simulation model, which can be used to predict the working characteristics and kinematical responses of the valve plates, as well as the flow characteristics, transient fluid pressure and velocity distribution of the shock absorbers. The working characteristics obtained from the simulation model are compared with the experimental results to prove the effectiveness of the simulation model. It is shown that the dynamic characteristics of the shock absorber can be predicted quite accurately by the 3-D FSI simulation model, which is meaningful to the understanding of the inner working mechanism of the shock absorber system.

The influence of friction parameters in a ball-screw energy-harvesting shock absorber

Energy-harvesting shock absorbers (EHSAs) have been introduced in the last decade as a viable technology for improving the performance and durability of electric and/or hybrid vehicles. However, in order to gauge the potential that can be obtained from this technology in different environments, the computational models that are used should behave as close to reality as possible. One of the limiting factors in EHSAs, in terms of recoverable energy, is frictional losses between its moving parts. Depending on the friction losses, the dynamics and efficiency of the system will vary. This paper presents a method of identifying the friction parameters in a ball-screw energy-harvesting shock absorber (BS-EHSA) system for subsequent computational simulation. In addition, it shows qualitative and quantitative results of how these friction parameters could affect the comfort and adhesion of the vehicle, as well as the generated power and energy efficiency of the BS-EHSA.

A Comprehensive Review on Regenerative Shock Absorber Systems

Regenerative shock absorber systems have become more attractive to researchers and industries in the past decade. Vibration occurs between the road surface and car body when driving on irregular road surfaces. The function of regenerative shock absorbers is to recover this vibration energy, which can be dissipated in the form of heat as waste. In this paper, the development of regenerative shock absorber is reviewed. This paper first introduces the existing research and significance of regenerative shock absorbers and reviews the potential of automotive vibration energy recovery techniques; then, it classifies and summarises the general classifications of regenerative shock absorbers. Finally, this study analyses the modelling and simulation of shock absorbers, actuators and dampers. Results show a great potential of energy recovery from automobile suspension vibration. And, the hydraulic and electrical regenerative structures exhibit excellent performance, with great potential for development. Regenerative shock absorbers have become a promising trend for vehicles because of the increasingly prominent energy issues.

Spring-Based Active Shock Absorber Systems with Piezoelectric Energy Harvesters.

In this research, energy harvesters with different types of spring-based shock absorbers were invested for the active shock absorber applications. Two different types of spring-based shock absorbers were prepared for the comparison, coil type spring-based shock absorbers and specially designed slice type spring-based shock absorbers. Shock absorbers have been widely employed to protect the complicated main system by cancelling the applied mechanical forces from outsides. Therefore, in the classical points of view, shock absorber can be prepared by the elastic materials to store and release the applied mechanical energy with sequentially in the form of elastic energy, thermal energy, and sound energy. However, in recently, there are strong demands to replace this classical shock absorber to the energy harvesters, which can collect the wasted energy in the form of electrical energy. Therefore, in this research, alternative two different types of spring-based advanced shock absorber will be presented and discussed. To combine with the spring-based shock absorber, multilayered piezoelectric energy harvesters were attached to collect the applied mechanical energy.

МЕТОД І ЗАСОБИ УТРИМАННЯ НАЗЕМНИХ ЗЛІТНО-ПОСАДКОВИХ ПЕРЕМІЩЕНЬ МОДИФІКАЦІЙ ЛІТАКІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ НА РІВНІ ЇХ БАЗОВОГО ВАРІАНТА

The problem of improving the takeoff and landing runway characteristics of heavier modifications of the transport category aircraft was further developed on the condition of equality of ground displacements of heavier modifications and their base variant by creating a method of formation of the “take-off mass - thrust-to-weight ratio” characteristics and using the fundamentally new local structures of additional slotted spoilers in extendable flaps and additional energetic chambers in landing gear shock absorber systems. The development of such a method and the use of additional slotted spoilers and energetic chambers in the shock absorber systems can provide for the basing of heavier modifications at the aerodromes assigned for the base aircraft.The problem of providing takeoff and landing characteristics (TLC) of more productive modifications of the transport category aircrafts is due to objective circumstances of ensuring their operation at the aerodromes assigned to the base aircraft on the basis of which the modifications are developed. The increase in productivity inevitably leads to an increase in the takeoff and landing mass and to an increase in the ground movements of modifications, i.e. the increase in the take-off and run distance, the distance of the rejected take-off and the required length of the runway. This increase significantly reduces flight safety.In the article the method of selection of basic parameters of modifications according to TLC deterministic values is proposed. The idea of the method lies in the fact that the main parameters of the modifications, such as take-off weight, thrust-to-weight ratio, specific load on the wing, etc., are selected from the condition that the main TLC of the modifications (takeoff run length, landing run, decision-making speed, distance length of rejected take-off and the required length of the runway) should be approximately the same with the similar parameters of the base version.By implementing this method, the areas for the existence of modifications of regional, mid-range and long-haul aircrafts within the coordinates "take-off mass-thrust-to-weight ratio" with a set of constraints, arising from changes in modifications, are determined. In addition, to implement such a method, it is proposed to use fundamentally new structures: additional slotted spoilers in extendable flaps and additional energetic chambers in the landing gear shock absorber systems. The development of such a method and the use of additional slotted spoilers and energetic chambers in the shock absorber systems can provide for the basing of heavier modifications at the aerodromes assigned for the base aircraft.The implementation of the conceptual provisions proposed in this paper and the use of AEC in the shock absorber systems for the modification of the An-140 aircraft and with an increased take-off weight (m0 = 3 t)of specific wing load of p = 432 kg / m2 allows:- to reduce the landing run of the aircraft modification by 136 m;- to keep the required runway length of An-140 modifications (m0 = 24 t) at the level of its basic version (m0 = 24 t) and, thus, to provide for the basing of heavier modifications of the An-140 aircraft on the airfields of the class 3;- to significantly improve the takeoff and landing characteristics of the basic version of An-140 (m0 = 21 t), i.e. to reduce the required length of the runway of this aircraft to 1150 m and thereby ensure its possible operation on the airfields of the class 4.