Types Of Shock Absorbers Research Articles

Study of relationship between motion of mechanisms in gas operated weapon and its shock absorber

The article deals with the motion of the breech block carrier and the weapon casing of an automatic weapon mounted on a flexible carriage and the base of the weapon. Earlier works, which did not consider the dynamic properties of the base of the weapon, did not allow to reconcile the calculated and experimental results of the weapon casing displacement when shooting from firing rests. For the analysis of the motion of individual parts, the methods of mathematical modelling and firing experiments using a high-speed camera were chosen. Calculations show the best accord with experiment when modelling the system with 4 degrees of freedom. The oscillation of the system regarding the movement of the breech block carrier and the weapon casing was investigated under changed conditions of rate of fire, the use of a muzzle brake and different types of shock absorbers. The velocities and displacements of the weapon casing and the breech block carrier at different values of the impulse of the gases to the breech block carrier were determined.

Analysis of a piezoelectric energy harvester system from footsteps of passersby

Piezoelectric materials can be used in applications designed to handle a wide range of input frequencies and forces to enable energy harvesting. Although several studies have been carried out on piezoelectric energy harvesting systems, this application is still under development. The purpose of this work is to analyze the behavior and the ability to generate electrical energy through the elements in piezoelectric tiles or platforms, specifically, piezoelectric disc elements with a diameter of 27 mm. To do this, a platform of about 130 x 75 cm was designed to capture the footsteps of people and transmit the impact force to sensors to determine the power generation capacity of the piezoelectric elements. Tests were carried out with people weighing between 75 kg and 85 kg and the measurements obtained made possible to identify the behavior of the system and to develop a mathematical model to estimate the energy generated through the platform. The piezoelectric elements used here proved to be fragile despite the different types of shock absorbers used to avoid their rupture. Therefore, it is recommended to delve into the design of protection mechanisms to extend the life of piezoelectric elements in energy collection systems.

Variable universe fuzzy control of the wheel loader semi-active cab suspension with multimode switching shock absorber

The aim of this work is to design a variable universe fuzzy control of a wheel loader semi-active cab suspension with damping multimode switching shock absorber. Considering the cost and reliability, a new type of shock absorber, whose adjustable damping characteristics are achieved by just changing the on–off statuses of two solenoid valves, is applied to the wheel loader cab suspension. The vibration model of the wheel loader, which considers the vibration characteristics of the working device, the four-wheel correlated random road excitation, and the engine vibration excitation simultaneously, is established first. Based on the working principle of the target shock absorber, the damping multi-state switching model is also established to reflect the relationship between the damping coefficients and the on–off statuses of two solenoid valves. Then, a variable universe fuzzy damping control strategy, which can determine the optimal switching sequences of the damping modes according to the cab suspension performance indexes, is designed. Finally, simulation analyses were conducted to verify the effectiveness of the proposed control approach of the wheel loader semi-active cab suspension with multimode switching shock absorber.

Calculations of vibration isolation systems by means of SCAS KiDyM in a nonlinear setting

The problem of vibration isolation of a device installed on four three-degree elastic shock absorbers with nonlinear characteristics, as an example of vibration isolation of a discrete system of arbitrary structure with several nonlinear elastic shock absorbers is considered in given paper. An analytical description of mechanical models is applied According to this description a special computer algebra system KiDyM (SCAS KiDyM) constructs differential equations of motion, linearizes inertial and elastic terms by means of elimination of the first small terms, carrying out harmonic linearization of the second one. After getting linear multi-mass mathematical model, the KiDyM software package performs calculations of free vibrations and presents the results in the form of skeletal curves. It allows to determine their sensitivity to the values of elastic and inertial parameters, It makes possible to carry out a cycle of calculations with varying model parameters to achieve optimal characteristics of the vibration protection system by shear and deformation of skeletal curves. An example of the problem analysis solution to the above-mentioned vibration protection system of a device performing spatial vibrations is given. Thus, the system contains 12 nonlinearities. The method for determining the experimental elastic characteristics for specimens of two types of shock absorbers is described. The possibilities of narrowing the spectrum of free vibrations by taking into account the nonlinearity of shock absorbers and the problem of skeletal curves construction of systems with several nonlinearities with generalized coordinates as the main coordinates of the oscillatory system.

Influence of the Damping System on the Vehicle Vibrations

The aim of the work was to evaluate the whole system of the springs of a passenger car. The influence of inflation and the type of tires on the acceleration of the various parts of the car (axle, steering wheel, driver's seat attachment, body shell and acceleration affecting the driver) was investigated. The types of shock absorbers and springs of the passenger car were also examined. The sensors used acceleration and pressure sensors between the wheel and the road using test stands. The benefits and reserves of the individual systems were compared, and in the systems with the cushioning rigidity, all the suspension setups were evaluated. The work was done experimentally in laboratory environment as well as in real operation.

Study of External Characteristics of Hydraulic Electromagnetic Regenerative Shock Absorber

According to the composition and the principle of the liquid-electric energy-sensing damper, the corresponding hydraulic regenerative model is designed. In this paper, an advanced type of shock absorber combined with the mechanical and electromagnetic hydraulic structure has been proposed that recycles the energy dissipated by shock absorber in the driving process. In addition, the damping characteristics of the conventional mechanical vehicle and the advanced hydraulic regenerative mechanical vehicle have been analyzed by using AMESim simulation. The regenerative suspension is reformed from the traditional hydraulic and pneumatic suspension. The suspension absorbs kinetic energy converts it into hydraulic potential and pneumatic power to be stored in the accumulator. The kinetic energy is then converted into electricity instead of heat by using the hydraulic suspension and Power-Generating Shock Absorber (PGSA). The AMESim simulation results have efficiently verified the displacement characteristics curves and flow rate of hydraulic fluid in the body. Finally the conversion of energy produced by advanced hydraulic regenerative mechanical vehicle transferred into electrical energy. The designed hydraulic shock absorber allows a significant fuel saving of 1.5% to 4% depending on the vehicle and driving conditions.

Analysis if shock absorbers efficiency in the eyes of Polish and Slovakian legislation

The construction of shock absorbers has changed over the years. With the technological development of cars, newer and newer models appeared. The technologies used in shock absorbers have been improved along with their development to meet the requirements of car manufacturers. The main purpose of using shock absorbers in the car is to ensure continuous contact of the wheels with the road surface and the comfort of driving by appropriate damping of vibrations captured from the body. Nowadays, many different types of shock absorbers are used, i.e. mechanical, hydraulic and hydraulic-pneumatic and many others which purpose and construction allows them to work in various atmospheric conditions all over the world. For this reason the shock absorbers of 30 cars traveling on Polish roads were examined at the vehicle inspection station. After the trails these results were contrasted with the legal provisions in force in Poland and Slovakia.

Design and analysis of a graded honeycomb shock absorber for a helicopter seat during a crash condition

ABSTRACTAn important issue that should be considered in accidents, including car, helicopter, and airplane crashes, is the safety of the human occupants. In this research, graded honeycomb structure is primarily introduced as a shock absorber. The amount of energy absorption, and the applied force and acceleration to the passengers have been calculated through numerical simulation in ABAQUS software. In order to validate numerical results, a low velocity experiment has been conducted on the test sample. Results represent an acceptable agreement with empirical ones. Given the occurrence of an emergency helicopter crash, it is of great importance to avoid any potential injurious loading to the passenger. Hence, according to Joint Aviation Regulations part 27, an optimised seat shock absorber has been designed and analysed for a helicopter in crash condition by the means of Genetic and Sequential Quadratic Programming algorithms. The designed shock absorber, which is of graded honeycomb structure, has satisfied complete standard specifications while being applied in the helicopter crash simulation. The applied design and simulation approach could be extended for any other types of shock absorbers.

Study of piezoelectric materials combined with electromagnetic design for bicycle harvesting system

Energy harvesting device involves capturing energy from the environment and it is increasingly crucial in the crisis of greenhouse effect nowadays. Equipping bicycles with many types of shock absorbers can enhance the riding comfort. Additionally, an embedded energy harvesting device will gain much benefit beyond the sports. This study applied the finite element method to analyze the components of nonlinear magnetic spring. The analytical simulations were conducted to analyze the electromagnetic effect in ANSYS©/Emag software. A model equipped with nonlinear magnetic springs was constructed to absorb the impact energy. Nevertheless, the piezoelectric components were used to capture the piezoelectric effect current caused by the compressive stress. A series of simulations were conducted, such as changing the diameter of the magnet, electric coil width, and the position of the coils. Moreover, with those finite element analysis data, the Taguchi method L9(34) orthogonal arrays were applied to determine the optimal parametric dimensions of the electromagnetic and piezoelectric assemblies for maximizing the captured kinetic energy and power transformation. The results could assist the suspension manufacturers to innovate their design for energy harvesting and impact absorbing.

Shock Absorber Using Hydraulic System and Shape Memory Alloys

A new type of shock absorber was designed. The shape memory alloy (SMA) bars were used as the kernel components for energy dissipation and restoration in the stress mode of pure tension. Their initial deformation was enlarged by the hydraulic system with two pistons of different sizes. In this way, high material utilization and high relative displacement were guaranteed together. The prototype device was fabricated, analyzed and experimental tested. The results show that the shape and amplitude of the force-displacement curve of the device could be easily changed by varying the hydraulic system, the number and/or the characteristics of the SMA bars. The new device can be separately or combined used as shock absorber and/or vibration isolation component for vehicles or other machines.

Analysis of MR Damper Based on Finite Element Approach

A magneto rheological damper is a damper filled with magneto rheological fluid, which is controlled by a magnetic field. This allows the damping characteristics of the shock absorber to be continuously controlled by varying the force of the electromagnet. This type of shock absorber has several applications, most notably in semi-active vehicle suspensions which may adapt to road conditions, as they are monitored through sensors in the vehicle. This paper presents magnetic saturation analysis of non-parametric model of magnetorheological (MR) damper using ANSYS for improvement of the higher force with optimal current and MATLAB/Simulink simulation for quarter car model equipped with MR damper to conduct dynamic studies of the system using skyhook controller and comparative study for passive and semi-active system.

Use of nonlinear asymmetrical shock absorber to improve comfort on passenger vehicles

Abstract In this study the behaviour of two different types of shock absorbers, symmetrical (linear) and asymmetrical (nonlinear) is compared for use on passenger vehicles. The analyses use different standard road inputs and include variation of the severity parameter, the asymmetry ratio and the velocity of the vehicle. Performance indices and acceleration values are used to assess the efficacy of the asymmetrical systems. The comparisons show that the asymmetrical system, with nonlinear characteristics, tends to have a smoother and more progressive performance, both for vertical and angular movements. The half-car front asymmetrical system was introduced, and the simulation results show that the use of the asymmetrical system only at the front of the vehicle can further diminish the angular oscillations. As lower levels of acceleration are essential for improved ride comfort, the use of asymmetrical systems for vibrations and impact absorption can be a more advantageous choice for passenger vehicles.

Performance Simulation of Hydraulic Energy-Regenerative Shock Absorber

This paper presents several kinds of energy-regenerative shock absorbers, which all exist some problems. Then, we put forward a novel type of shock absorber: Hydraulic Energy-regenerative Shock Absorber (HESA). In this paper, we focus on damping characteristic and energy recovery of HESA. Its feasible that damping force can be increased by adding a damping orifice in the extension stroke. The damping characteristic of HESA meets the requirements, whats more, it has great potential on energy recovery.

A Study on the Theory and Performance Simulation of the Hydraulic Electromagnetic Energy-Regenerative Shock Absorber

Hydraulic electromagnetic energy-regenerative shock absorber (HESA) is a new type of shock absorber which can regenerate a portion of energy dissipated as thermal energy in conventional shock absorber. This paper briefly describes HESAs working principle, uses AMESim, a hydraulic simulation software, to get damping characteristic of HESA as well as conventional passive shock absorber by doing some simulation tests, and contrasts the two consequents. Simulation results show that HESA has its unique damping characteristic, and its regenerative characteristic performs well.

The Operating Principle and Experimental Verification of the Hydraulic Electromagnetic Energy-Regenerative Shock Absorber

This paper introduces a new type of shock absorber: hydraulic electromagnetic energy-regenerative shock absorber (HESA), which can simultaneously implement the function of damping vibration and regenerating a portion of dissipated energies generated from passing through the damping hole. A test bench was trial-produced and used to prove the feasibility of the energy-regenerative scheme. The situation that hydraulic motor rotational speed has a sudden change in the energy regenerating process is theoretically analyzed.

Research of the dynamics of a magnetic fluid dynamic absorber

A new type of shock absorber using a magnetic fluid drop with the permanent magnet inside as a working element is investigated in this paper. Movement of the working element inside the body of the absorber under the influence of external oscillatory inertia forces leads to a viscous dissipation of the oscillating system energy. A theoretical model and some characteristics of the absorber are presented. This type of dynamic absorber is used nowadays in spacecraft technology.

Paper 2: The Application of a Small Scientific Computer to Calculations for Prototype Engines

It is often assumed that a large computer, because of its great speed and large core size, will invariably provide a cheaper result than a smaller computer. There are many problems in the internal combustion engine field, however, which can be tackled economically using a small scientific computer. Among these are design calculations for prototype engines where program utilization is not very high. The cost of developing these programs for a small machine is low and, providing the required output is matched to the speed of the machine, actual operating costs can be kept low. Many prototype designs give rise to problems where the solution warrants a computer, but time and money are such that a full scale study using a large machine is not possible. Here the small computer can be used to give a rapid economical answer to the problem while the relatively low cost of manual intervention on such a machine often allows a very flexible approach. Calculations for prototype engines described in this paper cover cam ordinates and their analysis and the determination of big-end bearing loads. Research problems include the effect of Poisson's ratio on thermal stress, a check on the motion of an unusual type of shock absorber and calculations to assist in the development of a small Stirling cycle engine.