Rear Shock Research Articles

Strength analysis and structural improvement of the connection between rear shock absorber support and frame of a city bus based on Hypermesh

Abstract In response to the phenomenon of cracking at the rivet holes of the plate connecting the rear shock absorber to the frame of the 6-meter leaf spring of the passenger bus, this article takes the rear shock absorber support and the frame as the research object. Firstly, CATIA software is used to model the object, and Hypermesh is used to divide the mesh to establish a fine element model. The Optistruct finite element solver is used to analyze the strength of the model, and the analysis results are imported into Hyperview 2019 for post-processing to analyze stress distribution and stress concentration. The simulation analysis results show that when a force of 6, 721 N is applied to the rear shock absorber support, the maximum stress value occurs at the rivet holes of the plate connecting the support to the frame, and the maximum equivalent stress value at this point is greater than the yield limit of the frame material, which is consistent with the crack location that occurs during actual vehicle operation. After adopting the strengthening scheme, the stress distribution of the frame is more uniform, greatly reducing stress concentration. The maximum stress value appears on the inner side of the right frame, and the maximum equivalent stress is less than the yield limit of the frame material, avoiding the crack phenomenon. The results indicate that this scheme can not only meet the performance requirements but also provide a reference for structural improvement and optimization design of the connection between the rear shock support and the frame.

Evaluation of reliability indicators of shock absorbers struts of M1 category cars in conditions of violation of established market relations between end users of spare parts and suppliers

Introduction. Over the past two years, there has been a violation of established market relations between end users of spare parts and suppliers. This led, on the one hand, to a significant increase in the cost of automotive components, and, on the other, to a reorientation of the market to new alternative manufacturers and suppliers. The main purpose of the work was a statistical assessment of the reliability indicators of the most expensive suspension element – the McPherson suspension strut, in the conditions of replacing the original struts with analogues available on the market.Methods. The study of the operational reliability of systems, components and assemblies of M1 cars was conducted in a dealership during 2022-2023. The study mainly involved cars with a sedan body and a McPherson front suspension. At the same time, the reason for contacting the service, the mileage of the car, as well as the types of work performed were recorded in each work order. The experimental data were processed using MSExcel and MatLab software from MathWorks.Resultsand conclusions. The conducted research allowed us to conclude that the appeals on the suspension of the car are almost twice as high as other appeals. The most expensive elements – the front shock struts, account for up to a third of all suspension failures. To assess the reliability indicators of alternative racks, the failure distribution law (normal), the probability of failure and uptime are determined, and the parameters of the distribution law are determined: mathematical expectation, standard deviation and coefficient of variation. It was found that the resource of the rear shock absorbers is at least 30% more, and there are significantly fewer calls at the service station. Thus, the operation of a car with racks from alternative manufacturers is quite reasonable, despite the fact that the resource of racks from alternative manufacturers is usually lower than that of the original brands.

Regulation Mechanism of the Shock Waves in a Pentamode Lattice-Ring Structure Subjected to Collision

This paper hopes to explore the application potential of pentamode materials in the field of shock protection. Hammer percussion tests revealed that the peak strain of the inner-ring front shock surface of the pentamode lattice-ring structure is 103.9% of that of the inner-ring rear shock surface. According to the simulation results, for a solid ring of equal mass made of the same base material, the ratio mentioned above reaches 3385.7%. Compared with the solid ring of equal mass made of the same base material, the pentamode lattice-ring structure saw a decline of 65.5% in the peak strain of its inner-ring front shock surface. The distribution laws of the group velocity characterizing energy-flow characteristics were discovered by calculating cell dispersion curves in various layers of the pentamode lattice-ring structure. The laws governing the effects of cellular structure parameters on group velocity anisotropy and pentamode characteristic parameters were also revealed. It was found that the deflection angle of the energy-flow vector is positively correlated with group velocity anisotropy and that the effects of pentamode characteristic parameters π and μ on the deflection angle of the energy-flow vector vary greatly in different value ranges. The deflection angle of the energy-flow vector has a decisive effect on the protection performance of the pentamode lattice-ring structure. The conclusions of this study can provide some theoretical support for the shock protection of submarine structures.

Multi-Spacecraft Observations of an Interplanetary Coronal Mass Ejection Interacting with Two Solar-Wind Regimes Observed by the Ulysses and Twin-STEREO Spacecraft

We present a combined study of a coronal mass ejection (CME), revealed in a unique orbital configuration that permits the analysis of remote-sensing observations on 27 June 2007 from the twin Solar Terrestrial Relations Observatory (STEREO)-A and -B spacecraft and of its subsequent in situ counterpart outside the ecliptic plane, the interplanetary coronal mass ejection (ICME) observed on 04 July 2007 by Ulysses at 1.5 AU and heliographic-Earth-ecliptic coordinates system (HEE) 33° latitude and 49° longitude. We apply a triangulation method to the STEREO Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) COR2 coronagraph images of the CME, and a self-similar expansion fitting method to STEREO/SECCHI Heliospheric Imager (HI)-B. At Ulysses we observe: a preceding forward shock, followed by a sheath region, a magnetic cloud, a rear forward shock, followed by a compression region due to a succeeding high-speed stream (HSS) interacting with the ICME. From a minimum variance analysis (MVA) and a length-scale analysis we infer that the magnetic cloud at Ulysses, with a duration of 24 h, has a west-north-east configuration, length scale of ≈0.2 AU, and mean expansion speed of 14.2 km s−1. The relatively small size of this ICME is likely to be a result of its interaction with the succeeding HSS. This ICME differs from the previously known over-expanding types observed by Ulysses, in that it straddles a region between the slow and fast solar wind that in itself drives the rear shock. We describe the agreements and limitations of these observations in comparison with 3D magneto-hydrodynamic (MHD) heliospheric simulations of the ICME in the context of a complex solar-wind environment.

Praktik Jual Beli Barter Sparepart Sepeda Motor Di Kelurahan Sadabuan Kota Padangsidimpuan Ditinjau Dari Kompilasi Hukum Ekonomi Syariah

The background of the problem in this research is the sale and purchase of spare parts motorcycles that are still in the credit period, but the debtor has default against one of the leasing companies in the city of Padangsidimpuan. As a result of the default, the leasing party will withdraw the motorcycle before the leasing party comes to recall the motorbike In this case, the debtor has sold some of the motorcycle spare parts with barter trading system. For example, such as rear shock (spring), tires and others. Whereas in the Compilation of Sharia Economic Law Article 266 which states: contains about Tenants are prohibited from renting and lending ijarah objects to other parties except with the permission of the party who rents out The formulation of the problem in this study is how to practice buying and selling motorcycle spare parts barter and a review of the Sharia Economic Law Compilation on the sale and purchase of motorcycle spare parts barter in the Sadabuan urban village Padangsidimpuan The method used in this research is the research method qualitative. As for the data collection techniques in the form of interviews and documentation. In this method, the data analysis used is descriptive that is, the researcher analyzes a systematic picture of what is happening in the field. Then perform an analysis of the findings by using adjust between findings and theory From the results that the practice of trading spare parts barter carried out in Sadabuan Village and the community have not fully complied with the requirements regarding buying and selling by barter which is contained in several provisions and can be eliminating the benefits, so the sale and purchase of spare parts is not in accordance with Compilation of Sharia Economic Law and because of the lack of clarity with objects or goods on the object being traded.

Investigation on conical separation vortex generated by swept shock wave/turbulent boundary layer interaction

To study the effects of Mach number, Reynolds number and deflection angle on the conical separation vortex generated by swept shock wave/turbulent boundary layer interaction , the experimental and numerical simulation methods are used. The Mach numbers are Ma=2.95 and Ma=4. The deflection angles are 12°, 15° and 18°. The incoming boundary layer thickness δ0.99 is 4.6 mm, 23 mm and 115 mm. The evolution characteristics of the vortex, including the vortex core position, the vortex area and the vortex intensity, and the effects of Mach number, Reynolds number and deflection angle on them are analyzed. The results show that the core trajectory of the vortex is distributed along the rear shock foot line of the λ shock structure. The Reynolds number is the main factor affecting the separation vortex core. The vortex area increases linearly along the direction of the inviscid shock, and the Reynolds number and the Mach number both are the factors affecting the growth rate of the separation vortex. The vortex intensity increases linearly along the direction of the inviscid shock. The vortex intensity is mainly affected by the Mach number and the deflection angle, but is not affected by the Reynolds number.

Simulation of Energy Absorption Performance of the Couplers in Urban Railway Vehicles during a Heavy Collision

Railway vehicles are generally operated by connecting several vehicles in a row. Mechanisms connecting railway vehicles must also absorb front and rear shock loads that occur during a train’s operation. To minimize damage, rail car couplers are equipped with a buffer system that absorbs the impact of energy. It is difficult to perform a crash test and evaluate performance by applying a buffer to an actual railway vehicle. In this study, a simulation technique using a mathematical buffer model was introduced to overcome these difficulties. For this, a model of each element of the buffer was built based on the experimental data for each element of the coupling buffer system and a collision simulation program was developed. The buffering characteristics of a 10-car train colliding at 25 km/h were analyzed using a developed simulator. The results of the heavy collision simulation showed that the rubber buffer was directly connected to the hydraulic shock absorber in a solid contact state, and displacement of the hydraulic buffer hardly occurred despite the increase in reaction force due to the high impact speed. Since the impact force is concentrated on the vehicle to which the collision is applied, it may be appropriate to apply a deformation tube with different characteristics depending on the vehicle location.

Controllable initiation characteristics of the oblique detonation wave in a combustor with a confined cone of a novel structure

The reliable and controllable initiation of the oblique detonation wave at an appropriate location is vital to maintain the optimal thrust of the propulsion systems. A novel structure is proposed in the current research to dynamically control the initiation of the oblique detonation wave in a combustor with a confined cone. The novel structure is based on the traditional single cone, of which the cone angle is θ0. The novel cone utilizes a leading cone with a smaller cone angle (θ1) + a larger rear cone angle (θ2), where θ1<θ0<θ2. A parametric study is conducted based on reactive Euler equations to test the performance of the novel structure on detonation initiation. It is found that the oblique detonation can be stabilized with less total pressure loss and less drag force under a wide range of Mach numbers. It is found that an ‘internal reflection’ of the rear shock wave exists in the first and second reflection of the leading shock wave. The ‘internal reflection’, which has not been reported before, enhances the temperature elevation and pressure elevation in the induction region of the oblique detonation wave. A possible strategy of dynamic control based on the novel structure is proposed. The force exerted on the rear cone is different under different Mach numbers, pushing the rear cone to a state of a certain cone angle. The novel structure performance very well for controllable initiation of the oblique detonation wave.

The analysis of factors influencing the trajectory of the vibrating screen

Due to the fact that the shape of the trajectory of the sieve vibrating screen significantly affects the efficiency of cleaning the drilling mud from the drilled rock, this article identifies and analyzes the factors influencing the formation of the trajectory of the sieve. The study of the nature of the motion of the particles of the drilled rock is carried out. The motion-equation of the point of the jigging frame, respectively, and a certain section of the screen can be described by an non-homogeneous second-order differential equation (Newton equation). The equation of the trajectory of the jigging frame is also considered. The influence of the amount of drilling mud, which is on the vibrating screen at a certain time-point, on the trajectory is taken into account in this equation. The drilling mud complex system consisting of liquid and solid fractions – sludge, sand and sludge – is taken into account. In this case, the fluid and clay move without separation from the sieve, and sludge and coagulated clay – with separation from the transport surface. Depending on the position on the sieve, each component of the drilling mud at different time periods moves with different trajectories and different other variable parameters along the length of the sieve. Therefore, the main purpose of the research is to obtain a graphical real trajectory of the selected point of the jigging frame of vibrating screens, to compare it with theoretical graphical dependences and to establish parameters that affect the change in the amplitude of jogging frame vibrations in real operating conditions. The coverage of the problem and the main results of the research are performed in real conditions (when vibrating screens work on the drilling rigs). The research is performed using simple recording devices installed at six places – on the left and right sides of the jigging frame above the front and rear shock absorbing springs, and in the center of stuff – between springs. All the real trajectories of certain points of the jigging frame and screen can be described using certain Lissajous figures. However, it was found that not all trajectories coincide completely with the classic Lissajous figures, because the trajectory is influenced by external factors that cause chaotic motion of the jigging frame – the Sommerfeld effect, as well as non-uniformity of drilling fluid delivery. The nature of the movement of the vibrating plane - the screen - is also affected by the rigidity of the vibrating support, including the entire structure of the vibrating screens. The phenomenon of resonance is possible in the area of ​​vibration supports. In addition, it was previously established that the trajectory of the point of a certain area of ​​the screen is a spatial figure that requires additional theoretical and experimental studies. When moving the drilling fluid on the sieve with the toss, the cleaning efficiency will be much higher due to the increase in vibration force. Based on the analysis of the results of the factors influencing the trajectory of the sieve, preliminary recommendations are given for the correct adjustment of the vibrating screen.

Experimental Study of a New Method for Reducing Airfoil Wave Drag at Transonic Speeds

This work proposes a new method for reducing the wave drag of an airfoil at transonic speeds, which consists in creating a section of a microwaved upper surface in the local supersonic zone. Weighted and physical studies are carried out for the initial and modified airfoils. It was experimentally established that the proposed new approach results in a system of weak compression waves, a gradual deceleration of the supersonic flow, and a decrease in the Mach number before the rear shock wave—and, as a result, a decrease in its intensity weakening and a decrease in wave drag.

A Numerical Investigation of the Geometric Parametrisation of Shock Control Bumps for Transonic Shock Oscillation Control

At transonic flight conditions, shock oscillations on wing surfaces are known to occur and result in degraded aerodynamic performance and handling qualities. This is a purely flow-driven phenomenon, known as transonic buffet, that causes limit cycle oscillations and may present itself within the operational flight envelope. Hence, there is significant research interest in the development of shock control techniques to either stabilise the unsteady flow or raise the boundary onset. This paper explores the efficacy of dynamically activated contour-based shock control bumps within the buffet envelope of the OAT15A aerofoil on transonic flow control numerically through unsteady Reynolds-averaged Navier–Stokes modelling. A parametric evaluation of the geometric variables that define the Hicks–Henne-derived shock control bump will show that bumps of this type lead to a large design space of applicable shapes for buffet suppression. Assessment of the flow field, local to the deployed shock control bump geometries, reveals that control is achieved through a weakening of the rear shock leg, combined with the formation of dual re-circulatory cells within the separated shear-layer. Within this design space, favourable aerodynamic performance can also be achieved. The off-design performance of two optimal shock control bump configurations is explored over the buffet region for M = 0.73, where the designs demonstrate the ability to suppress shock oscillations deep into the buffet envelope.

A novel interval analysis method to identify and reduce pure electric vehicle structure-borne noise

The interior noise of a pure electric vehicle (EV) is quieter than that of a traditional internal combustion engine vehicle (ICEV). However, if the noise masking effect of an ICEV is not employed, structure-borne noise from the suspension in an EV will become prevalent, although the interior noise weakens when the EV is driven at a moderate speed. Identifying the sources of suspension structure-borne noise is necessary to reduce the interior noise in an EV and improve the vehicle sound quality. However, the suspension system comprises many components and noise sources, making the identification and reduction of suspension structure-borne noise in an EV a challenging task. In this paper, a new noise source identification method based on interval analysis is proposed. This method can not only accurately identify the sources of noise but also provide details regarding modification methods for reducing interior noise. To implement this method, a test EV was used for measurement, and 15 tests constructed through experimental design were carried out to record the interior noise and vibrations of suspension components. The results showed that the suspension structure-borne noise of the test vehicle was distributed mainly below a frequency of 400 Hz. The feasible intervals and noise source contributions were calculated via the interval analysis method, and the front spring and rear shock absorber were identified as the major sources of suspension structure-borne noise. In addition, component parameters were optimized through the interval analysis method. In accordance with the suggested modification method, a verification test was implemented, illustrating that the EV interior noise quality was improved and validating the effectiveness of the proposed method. The presented approach may be regarded as a promising method for identifying and optimizing vehicle noise sources.

Design and Optimization of Suspension and Steering System of Efficycle – Human Powered Hybrid Tricycle

Suspension is a system of tires, springs, shock absorbers, and linkages that connects a vehicle’s chassis to its wheels and allows relative motion between the two. Steering is a mechanism that provides a direction to the vehicle, it basically consists of gears, shaft, joints, steering column, steering wheel, and furthermore. The main objective of this paper is to design a system of suspension and steering for a three-wheeled human-electric hybrid trike. A system of directly actuated double wishbone suspension system is chosen for the front and a pushrod actuated 2-link trailing arm suspension system for the rear. The steering system used is a type of Single tie rod and drag link system. A knuckle-to-knuckle drag link provides continuity to the wheels and a tie rod to the bell crank provides steering rotation. This paper also talks about the single nut hub-shaft system which is being used in the front suspension system. Based on the research using various input parameters, the inboard and outboard suspension hardpoints are decided to maximize the tire contact patch at every vehicular motion (mainly during body roll). Forces and stresses are calculated with the help of Free Body Diagrams (FBD) and Multi-Body Dynamics (MBD) software LOTUS Shark. The paper discusses the calculations regarding the roll and ride rates and for the custom springs of specific stiffness used in front and rear shock absorbers and the variation of roll steer and bump steer on changing various parameters of the steering system. Key points also include the procedure of selections of various types of bearings, rod ends, and bolts. This paper also talks about laser-cut jigsaw uprights that are used in the front wheel assembly. The finite element method was used to analyze the designs using DS Solidworks and Ansys Workbench. Static structural and explicit dynamics analysis was performed on the wheel assembly components both individually and assembled

Process Optimization on Rear Bumper Assembly in a PIM Two Wheels Poly Company

The article discusses the relevance of a proper implementation for the rear shock absorber assembly line of motorcycles in a company of Manaus Industrial Pole - PIM, considering the quality techniques and tools used in optimizations. The overall goal is to improve component distribution and rear shock mounting costs for efficiency and effectiveness in the process flow. Specific objectives are to: Avoid wasting time in the process, improve production with optimization techniques, and develop team capacity. In the problem, he observed jobs 6 and 7 with poor “distribution” of components, generating excessive spending. The question arises: How can component “redistribution” optimize and reduce costs for the business? The methodology used was exploratory research, with systematized studies through academic websites, books, bibliographic research and field research with the company with collected data. The optimization procedures were performed with the following tools: Brainstorming, Ishikawa Diagram, 5W2H and Kaizen. Therefore, this paper aims to develop knowledge about the improvements implemented in the assembly line, encouraging the application of quality tools, making it a very efficient option for the organization.

Analysis of Rear Shock Absorber spring of a Two Wheeler

Analysis of Rear Shock Absorber spring of a Two Wheeler

Study on the effects of geometry on the initiation characteristics of the oblique detonation wave for hydrogen-air mixture

The Oblique Detonation Wave Engine (ODWE) may act as a hypersonic propulsion system operating at high Mach numbers, which is an important member in the family of Scramjet. Hydrogen is a promising fuel for Scramjet, which provides wider Mach number range and is environmentally friendly. The geometry of the engine greatly affects the performance of the ODWE using hydrogen fuel. This investigation focuses on a novel wedge proposed recently, which may be utilized in scramjet engines. The wedge consists of two sub-wedges and a step. This research focuses on how the geometry of the wedge affects the initiation characteristics of the oblique detonation. Simulations are conducted on basis of Euler equations and a 9-species and 19-reactions mechanism. It is found that a larger leading wedge angle leads to a shorter initiation length. A larger step angle induces a longer initiation length. Few effects are observed on the initiation characteristics for the current range of depth. The streamline surface at the rear of the step weakens the rear shock wave and induces a longer initiation length. The streamline surface at the tip of the step begins to take effect when the initiation position is away from the step. This research provides basis for understanding the performance of the oblique detonation wave under different geometries and provides theoretical basis for scramjet engine design.

Parameter study and optimization of a half-vehicle suspension system model integrated with an arm-teeth regenerative shock absorber using Taguchi method

Abstract This paper presents a novel regenerative shock absorber that utilizes an arm-teeth mechanism to convert linear to rotational motion and to amplify the generator input speed. The flywheel of the arm-teeth mechanism also acts as an energy-storing element, allowing for smooth operation especially on a rough and uneven road surface. The critical parameters are identified through experiments and the simulation model is established based on a half-vehicle suspension system model. The novelty of this work is the proposed arm-teeth mechanism and the optimization of the half-vehicle suspension system through the Taguchi method. In this method, the ratio of the peak output power over the squared excitation displacement amplitude and the frequency bandwidth of the front and rear shock absorbers are set as targets and evaluated respectively. The effects of each parameter on the targets and the optimal parameter combinations are identified through the Taguchi matrix calculations. The optimized system is evaluated under the excitation of the road surface profiles of Class A, C and E of ISO 8606. It is found that the optimized system is able to harvest more energy with a broader frequency bandwidth than the original system at a certain speed for all three random road profile classifications.

Sensitivity Test of the Influence of the Performance Parameters of the Main Suspension Components of a Certain MPV on the Interior Noise of the Vehicle

In the process of a domestic MPV development, it is found that there is a large noise in the vehicle at a constant speed. Through TPA analysis, it is found that road excitation is primary, and the frequency is distributed between 75-400Hz. In response to solve the question, the influence sensitivity of the performance parameters of the suspension system on the interior noise of the vehicle is studied after the modal of the chassis structure is analyzed, such as leaf spring stiffness, shock absorber damping force, tire pressure. Test results found that in the low-speed rough road several factors affect the sensitivity of driver’s right ear, from large to small in order that is tire pressure, leaf spring stiffness, front damper damping force, rear shock absorber damping force. Ultimately through the combination of these parameters the noise of the driver’s right ear was reduced further and reached the target value. The results of this study have some reference value for similar NVH problem to other vehicles.

The use of optical methods for measuring irregular reflection of weak acoustic shock pulses from a solid surface in air

Irregular reflection ofacoustic weak shockwaves (acoustic Mach numbers less than 0.01) is known as the von Neumann paradox and could not be described by the three-shock theory. In this work, nonlinear reflection regimes were studied experimentally using spark-generated spherically divergent N-waves reflecting from a plane rigid surface. Two optical methods were used in the measurements: a Schlieren system to visualize reflection patterns and a Mach-Zehnder interferometer to reconstruct pressure waveforms. The reconstruction was performed by applying the inverse Abel transform to the phase of the signal measured by the interferometer. The Mach stem formation was observed close to the surface as a result of collision of the incident and reflected front shocks of the N-wave and further away from the surface where the reflected front shock interacted with the incident rear shock. It was shown that irregular reflection occurred in a dynamic way and the length of the Mach stem increased while the N-wave propagated along the surface. In addition, reflection patterns were analyzed for several rough plane surfaces with different roughness size. The height of the Mash stem was found shorter for surfaces with larger dimension of the roughness.

Transient dynamic impact suppression of a Baja chassis using frontal and rear shock absorbers

ABSTRACTThis paper investigates the behaviour of impact loading on a Baja vehicle chassis with frontal and rear shock absorbers, using transient dynamic analysis under different assumptions of contact conditions. Using a Baja car, a transient dynamic impact is performed in ANSYS Workbench 14.0, where the maximum deformation, stress and strains are calculated over duration of the particular impact. The mathematical model of the chassis is derived based on Kelvin model in order to design the best parameters of stiffness and damping coefficient in shock absorbers to minimise the deformation of the frame with the same impact. To study the effects of shock absorber under loading on a vehicle chassis, multiple finite element simulations are performed with different methodologies. Each methodology uses a different assumption on loading and boundary conditions, which leads to different results.