Front Beam Research Articles

Finite element analysis regarding folding behaviour of different crashbox versions

Low-speed collision is one of the most frequent road accident types nowadays. The consequences of this accident could be serious and long terminated. The passive safety system has an important role to reduce and prevent the amount of personal and technical injuries. Applying front and rear bumper beams is a good way to absorb more impact energy at the moment of collision reducing the load of the occupants. The background of the energy absorbing is the prescribed folding deformation of the bumper's support namely the crashbox. The main goal of the present study is to evaluate and compare differently shaped crashboxes as a thin-walled structure using finite element analysing to get information for more effective energy absorption taking into consideration of the weight optimization and spce requirements. To be comparable to the folding fluctuation of each specimen the compression test's curves are evaluated with relative standard density. Moreover, the specific energy absorption is also was determined. Based on the values determined by finite element analysis conclusions could be drawn.

Fiber laser cutting of steel plate by twin spot beam setting in scanning direction

This study investigated the effects of laser beam intensity distribution on the reduction of dross height in fiber laser cutting of a steel plate with 3.2 mm thickness. A twin-spot beam was produced by splitting a single Gaussian beam into two beams using a special axicon lens, and these beams were set in the scanning direction for cutting experiments. The power ratio of two beams (R:F = Rear power:Front power) was varied to discuss the intensity balance for the effective reduction of dross. After cutting experiments, ray tracing analysis was conducted using an optical analysis to calculate the absorbed power density distributions in the kerf. A smaller dross height of 18 μm can be achieved at a power ratio of R:F = 8:2, and its value is lower than that by a single Gaussian beam. At a power ratio of R:F = 8:2, the front beam of lower power is irradiated at the upper part of the workpiece, and the rear beam of higher power is absorbed at the lower part of the workpiece. Thus, effective heat input to the lower part of the workpiece can contribute to a reduction of the dross height. Variation of power ratio in the rear and the front beams is effective in controlling the cutting front shape, and the uniformity of absorbed power in the thickness direction can be improved by setting the rear beam of about four times higher power to the front beam of lower power to obtain a smaller dross height in the case of a 3.2 mm steel plate.

Topology Optimization and Analysis of the Compound Boring and Milling Machining Center TX1600g Bed Structure

The overall performance of the machine tool bed of the boring and milling center has an important impact on the accuracy of the overall machining, in order to improve the machining accuracy and structural performance of the overall machine tool, the structure optimization design of the machine bed is carried out for the TX1600g composite boring and milling center. The maximum static displacement and mass of the bed were used as the evaluation index to optimize the topology and structure of the bed. An orthogonal test of 5 factors and 5 levels was designed, the maximum displacement generated by different positions in work was analyzed, the frequency under this working condition was explored, and modal analysis was conducted. The Hyperwork selective variable density method is used to optimize the beam structure with multiple objective topologies. By comparing and optimizing the performance parameters of the front and rear beams, the total static displacement is reduced by 9%, which proves the effectiveness of this method to solve the multi-objective optimization problem.

Experimental determination of vibration conductivity by rocket sled structural elements in high-speed track tests of aircraft equipment

The development of new ballistic-type aircraft is characterized primarily by improved aerodynamic characteristics and higher speed limits. Ground track testing of aviation and rocket technology is a stage whose task is to confirm the efficiency and effectiveness of new developments. Track tests make it possible to simulate real loads, they are simpler and much cheaper than flight tests. Experimental installation "Rocket rail track 3500" of Scientific Test Range of Aviation Systems named after L. K. Safronov is constantly being upgraded in order to conduct track tests of products at a speed greater than 3M. The experimental setup includes a two-rail track, made on a special foundation, which excludes unacceptable rail deflection with a mass of up to 3000 kg. The rail track has an acceleration section with an angle of attack 2500 m long and a deceleration section. A tray filled with water is made on the braking section between the track rails. It is designed for hydrodynamic braking to a complete stop of the rocket sled with stored equipment. The movable rocket track sled is made of a massive steel plate to which three cross beams are welded. The front and rear beams end with axles on which sliding supports are pivotally mounted. On the rear and middle beams there are lodgements for fastening rocket engines of solid fuel. Depending on the required test speed, from one to five motors can be placed on the cradles. The test object is usually mounted on the front and middle beams along the axis of the sled and fixed in a cantilever, with the head part extended forward. The design of the supports - shoes is made to encircle the rail head in such a way that it provides sliding contact along the upper plane of the rail head, and in the event of a lifting force exceeding the weight of the sled at high speeds, it keeps the structure from free flight by contacting the lower surface of the rail head. Track high-speed tests of special equipment objects are always accompanied by intense vibration and shock effects of structural elements. Due to the desire to conduct track testing of products at a faster rate, it becomes necessary to reduce the level of dynamic loads and eliminate resonant interactions. The article presents an algorithm and methodology! for statistical processing of random signals of three-axis vibration acceleration sensors installed on the shoes of the rocket track sled and on the fairing of the test object. Due to the placement of registration data storage devices on the sled, experimental vibration data were stored when testing the product at a speed of more than IM. The autocorrelation functions of the signals of vibration accelerations of sensors placed on various elements of the rocket sled, the functions of mutual correlation of the corresponding signals, the density of the amplitude spectra, the density of the power spectra and the transfer functions that characterize the dynamic conductivity of vibrations from the shoes sliding along the rail guides to the test object were determined.

Wheeled tractor equipped with a mechanism for changing the ground clearance

In accordance with the agricultural row-crops cultivation practices adopted in the Central Asian region, machine-tractor units carry out a large number of passes through the field during the growing season. Consequently, individual sections of the fields are repeatedly affected by the running systems of these machines, which negatively affects soil fertility. The universal row-crop tractors used in cotton production have two types of wheel arrangements: 3W2 and 4W2. Consequently, these arrangements have different natures and magnitude of impact on the soil. Despite a number of advantages of 4-wheeled tractors due to insufficient agrotechnical clearance under the front and rear axles beam, they are not used for inter-row cotton cultivation. Mechanisms including a stepless change in ground clearance, both for the front and rear axles of a 4-wheeled tractor, eliminate these disadvantages and thereby expand the possibilities of their use. The use of a 4-wheeled tractor in field and transport operations has shown that the most loaded parts in the developed mechanism for changing the clearance of the rear axle are rolling supports of the cage on the casing of the rear axle of the tractor.

HIL simulation of high-speed train active stability employing active inertial actuators

ABSTRACT To enhance the lateral stability of a certain type of high-speed train under bogie’s active control, characteristics of inertial actuators that generate control force in the active control system are studied, the control delay of the whole Hardware-in-the-Loop (HIL) system is measured, and multi-objective optimisation for feedback parameters with or without the control delay is achieved in this study. A linear model of bogie lateral dynamics, with two inertial actuators, acting on the front and rear end beams, is established for the optimisation. Correspondingly, a nonlinear vehicle model is established in the Simpack platform for both mathematical simulation and HIL simulation to verify the control effects. As the force source of active control, dynamic characteristics of the inertial actuator with different control strategies are examined. Multi-objective optimal control is carried out on the linear active bogie models with and without the delay measured in the experiment to improve the bogie hunting stability. The control method is then evaluated in a nonlinear vehicle model and HIL simulation. Simulation results show that the lateral dynamic performance of the high-speed train can be effectively improved with the active stability system even with a large time delay.

Deep learning-based optimization of a hydrogen and oxygen production system for patients in hospital with alkaline electrolyzer

The hybrid renewable system's potential to create standard type E capsules for Covid-19 patients was explored in this study. In addition to delivering the requisite energy to the building, standard oxygen capsules were produced using the electrolysis of water using nanomaterial-supported electrolysis in the hydrogen storage system. In addition to the simulation, multi-objective optimization was done using a deep learning neural network and a genetic algorithm to maximize the number of oxygen capsules generated in a year and the system price, and the system's front beam was acquired. The system can produce 19530 units of type E oxygen capsules in a year, and the price of the electrolyzer and fuel cell is 120296 Euros at the best point of the front beam, considering both the objective variable of price and the number of produced oxygen capsules. In this scenario, the electrolyzer and fuel cell have rated powers of 61.9 kW and 15.3 kW, respectively. After determining the optimal point, researchers investigatedthe connection between meteorological data and other system characteristics including the amount of hydrogen in the tank, the number of oxygen capsules generated each hour, fuel cell power, and the electrolyzer. Lastly, the system's capacity to lower the amount of power required for the office building from the municipal network was investigated, indicating the system's excellent capability in this respect.

Оцінка міцності та надійності автотранспортних засобів

At present, the issue of ensuring the strength and reliability of wheeled vehicles, the creation of which requires compliance with all modern requirements, has not been fully resolved. In this regard, improving the methodology for assessing the strength and reliability of vehicles is an urgent task, the solution of which involves finding answers to the following questions: the choice of a rational version of the bearing system and economically sound profiles; selection of materials with appropriate physical and mechanical characteristics, etc. The choice of a rational variant of the load-bearing system of frame structures of vehicles requires a comparative assessment of possible options at all stages of design work. The load-bearing structures of vehicles are statically uncertain. Therefore, the process of assessing the strength and reliability of vehicles with different types of design schemes is a complex task, which today does not have a single methodological solution. In order to solve this problem, the model of the stress-strain state of the spatially loaded frame structure of the HESSTON S 125 solid fertilizer spreader is considered by a modified method of minimum potential deformation energy of structural structures using the Heaviside function. The frame is a welded load-bearing structure consisting of three longitudinal spars connected by a front beam and crossbars. Carrying out the correct and rational analysis of the stress-strain state of such a bearing system is possible only with the use of a modified method of minimum potential deformation energy. As a result of modeling, recommendations were obtained for the rational design of components and components of wheeled vehicles with increased reliability while reducing material consumption. Ultimately, this leads to an increase in their strength and reliability while reducing material consumption.

Dynamic analysis of the performance of the mechanism for changing the base of a four-wheel tractor

A mechanism is developed for changing the base of a tractor operating on bogharic and arable lands with an uneven surface in mountainous and foothill areas. When using the Ц100 hydraulic cylinder as a working power body, the operability of the proposed mechanism on all supporting surfaces was confirmed. Keywords: base, front beam, spar, hydraulic cylinder, loading, maneuverability. tractor-v@mail.ru, abrorkarimov@bk.ru, kdu.317@mail.ru

Comparative study of numerical simulation methods for seismic pounding of adjacent girder of curved girder bridges

Under seismic action, non-uniform collision will occur between the main beams of curved beam bridge, which may lead to local damage of front beam or rear beam. At present, the research on collision effect is mainly based on straight beam bridge, and there is still a lack of relevant research on seismic collision of curved beam bridge. Taking two adjacent typical curved bridges as examples, this paper establishes contact elements (linear elastic model, Kelvin model and Hertz model) and solid elements (three-dimensional contact friction model) which can fully reflect the physical characteristics of seismic collision of curved bridges. By comparing the numerical simulation methods of seismic collision, the advantages and disadvantages of the existing numerical simulation methods in the seismic response analysis of curved bridges are evaluated. The results show that the calculation results of Kelvin model and three-dimensional contact friction model have the least error and high calculation efficiency, and are suitable for the seismic analysis of curved beam bridges.

Conical phase front and aberration beam shaping for manipulating femtosecond laser chemical etching

The countering and enhancing influence of surface aberration in combination with conical phase front beam shaping was examined over shallow to deep focusing inside of fused silica to facilitate the geometric control of chemical etching tracks formed by femtosecond laser inscription. The tuning of the collective shaping effects is shown to compensate for a wide focusing range to favorably manipulate the chemical etching rate, the resolution, the surface roughness, and the cross-section profile of the resulting micro-channels. Using only a single laser scanning track, micro-channels have been tailored from symmetrical to highly asymmetric cross-section of up to 1:13 aspect ratio, permitting distortion-free processing to depths of 1.5 mm. The combined shaping effects thus expand the utility of laser chemical etching for micromachining of transparent substrates.

Testing of bicycle lighting: Method development and evaluation

In darkness it is legally obligatory to light vehicles, both to enable their operators to see where they are travelling and to make the vehicle visible and recognisable to other road users. Legal requirements differ between vehicle types and, for bicycle lighting, also between countries. So far, in spite of some indications, there is no definite evidence of a relationship between crashes involving cyclists and darkness, nor on the presence of bicycle lighting and crash risk in darkness, possibly due to a lack of prevalence data. There are no standards for scientific or consumer testing of bicycle lights, and visibility-related results are inconclusive. Three test methods were employed to evaluate generic bicycle light features such as beam shape, brightness, steady versus flashing beam, and mounting position for their effects on seeing and being seen, while investigating which method was best suited for which type of evaluation. In static indoor laboratory testing, brightness was measured and beam shape documented photographically. In static outdoor testing, visibility from 300 m was evaluated, subjective ratings were collected, and beam shape documented. Three front-light beam types were then evaluated for their effect on gap acceptance in a dynamic setting in an urban environment, and subjective ratings were collected. All 18 tested lamps fulfilled the legal requirements, with a bright, steady front beam receiving the highest subjective ratings. Gap acceptance was influenced only by cyclist speed, but neither by beam type nor mounting position. To capture the effect of generic bicycle light features on perception, behaviour, and acceptance, one single method is not enough, and standardised laboratory tests should be combined with research-question–specific dynamic testing.

Research on Transfer Characteristics of Engine Vibration Load to Cabin Seat

Aeroengine is one of the main vibration sources that affect the passenger comfort. The contribution of engine vibration to the vibration response of seat will provide basic data for the design of airliner vibration comfort and engine vibration isolation installation. Firstly, the dynamical model of middle fuselage compartment with double-beam wing was established. Then, based on the typical vibration load spectrum of the engine, the acceleration responses of the key nodes of the wing beam and the seat connection points were analyzed, and the main path of engine vibration transmission to seats was identified. Finally, using operational transfer path analysis (OTPA) method, the contribution of engine front and rear mount point vibration to the vertical acceleration response of the seats was compared, and the three-dimensional information of wing structure vibration transmission was explored. The results show that the fundamental frequency component of low-pressure rotor of engine vibration has the greatest impact on the seat vertical response under takeoff and cruise conditions, the contribution rate of the front mount point vibration is about 71% and 67% respectively. However, the fundamental and its 3/2 times frequency components of high-pressure rotor have relatively large impact on the seats vertical response under flight idle state, and the contribution rate of engine front mount point vibration is about 45% and 60% respectively. In addition, the engine vibration is mainly transmitted from the wing front beam to the seat vertical response. The vertical direction of the wing beam and the rotation direction around the fuselage are also the main direction of vibration transmission.

The fracturing models of hard roofs and spatiotemporal law of mining-induced stress in a top coal caving face with an extra-thick coal seam

Hard roof fracturing characteristics and mining-induced stress behaviors can be studied to ensure production safety in top coal caving face. Field tests were conducted at top coal caving face No. 8309 in the Tongxin mine of the Datong Coal Mining Group in China. The monitoring results indicated two modes of periodic weighting: short weighting steps with low intensity and long weighting steps with high intensity. According to three periodic weighting phenomena, three models of hard roof fracturing were proposed based on the cantilever-voussoir beam compound structure. And the equations of the working resistance for long/high periodic weighting were derived. Furthermore, a difference in the pressure changes among the front leg, back leg and front beam of the supports was observed, and the back leg pressure significantly increased during periodic weighting. The change in the single prop pressure was divided into a slow growth stage and a rapid growth stage. And the front abutment pressure fluctuated with the periodic instability of the roof compound structure. Moreover, the fracturing of the roof above the stope resulted in roadway deformation. The instability of the cantilever-voussoir beam structure also intensified the roadway deformation. Finally, a support-surrounding rock mechanical model was established considering the behavior of an elastic cantilever beam. The required work resistance considering the bearing capacity of top coal were discussed, providing a basis for reasonable support selection. These research results can provide references for mining pressure and stratum movement control.

Improvement of oscillation characteristics of ring oscillator through photoconductivity and dielectric constant of photorefractive materials

The intensity of oscillation and the oscillation frequency shift are two most important parameters that characterize the performance of a photorefractive ring oscillator. In this paper, the effect of photoconductivity and dielectric constant of photorefractive (PR) materials on these parameters has been studied in case of non-degenerate two-wave mixing in PR materials. It has been found that for a given value of photoconductivity of PR material, the highly reflecting ( $$ R > 90\% $$ ) cavity mirrors are much effective parameter as compared to the other parameters (frequency detuning, absorption strength, energy beam coupling strength and dielectric constant) for the enhancement of the intensity of oscillation in the oscillator. Also, the magnitude of oscillation frequency of the photorefractive ring oscillator (PRO) can be increased by inserting PR crystal of lower dielectric constant ( $$ \varepsilon < 7.0 $$ ), higher photoconductivity ( $$ \sigma_{\text{p}} > 500\,{\text{pS/cm}} $$ ) and highly reflectivity ( $$ R > 90\% $$ ) cavity mirrors provided that the cavity-length detuning $$ \left( {\frac{\Delta \varGamma }{\pi } > 1.0} \right) $$ of the oscillator is higher. This means that the intensity and frequency of the PRO could be controlled by the dielectric constant and photoconductivity of a PR crystal which would greatly improve performance of a PRO and their applications based on these photorefractive ring oscillators such as wave front color conversion, optical limiting, optical computing and beam cleanup.

Analysis of the frame design of the subcompact racing car of go-kart class

The article presents the design features of subcompact small-capacity racing car of kart class. The issues of the strength of the supporting structure are considered. The main strength characteristics of the material AISI-1020 are presented, which was used in the design of the frame chassis. A conceptual block diagram of a methodology for designing a supporting structure model using engineering analysis methods (finite element modeling) is presented. The analysis of structural strength using ANSYS software is carried out. The rode type finite element model of the frame is presented. The directions of application and values of the resulting loads are determined taking into account the overloads experienced by the pilot in collisions. The boundary conditions and the deformation pattern of the frame structure when applying the deforming forces to the front beam along the longitudinal axis of the car, outside the longitudinal axis of the car and on the lateral truss of the car frame are given. The engineering analysis data show a good coincidence of the modeling results with the experimental data.

Actuator optimal placement studies of high-speed power bogie for active hunting stability

ABSTRACTWe put forward three actuator placements of the high-speed train power bogie to improve the train hunting stability. The active control forces act on the frame, between the frame and the motor, and on the motor by the inertial or retractable actuator, respectively, based on the feedback states of vibration velocity of the front and rear end beams. The feedback gains and the motor suspension parameters in different cases are optimised with the two objectives of system stability margin and control effort. The required actuator outputs of the three cases are compared based on the theoretical analysis with a 8 DOF bogie model. The results show that the three control cases can effectively improve the hunting stability, especially at high speed. The active control of motor lateral movement is helpful to increase the dynamic vibration absorbing function of the motor flexible suspension, and the control output is obviously smaller than the other two control cases. In addition, the influence of system delay on stability was analysed and we could use or avoid the effects of delay on the stability.

Proposition of a femtosecond pulse radiolysis with terahertz probe pulses

A new concept of pulse radiolysis based on a photoinjector, which can synchronously offer femtosecond (fs) pump electron beams and intense Terahertz (THz) probe pulses, is proposed and studied in this paper. The two electron beams are generated in the radio-frequency (rf) electron gun by illuminating the photocathode with two laser pulses, then compressed and accelerated in two linear accelerators respectively. By applying the brake-applied velocity bunching bunch compression method, a few hundreds of fs electron beams with nano-Coulomb (nC) bunch charge can be obtained. The front beam can generate THz pulse with MW peak power for THz probe, and the rear beam is used to pumping the radiation induced phenomena. This new concept pulse radiolysis scheme provides a promising way for high time resolution pump-probe experiments with a novel experimental methodology.

A structural crack monitoring gasket for aircraft bolt-jointed structures with temperature compensation

In order to meet the need of the quantitative monitoring of cracks in critical connection structures of aircraft, aiming at improving the durability of sensors and the reliability of signals, a structural crack monitoring (SCM) gasket, which can be used for the quantitative monitoring of cracks in bolted joints, is developed. The gasket is formed by a gasket substrate and a flexible eddy current sensor integrated to withstand the load, with the capability of temperature compensation. First of all, a new temperature-compensated rosette eddy current array (TC-RECA) sensor is designed and used to study the failure mode of the sensor. According to the failure mode of the sensor, a gasket substrate with load-bearing capacity is developed. Subsequently, the influence of permeability, conductivity and lift-off on the trans-impedance of the sensor is studied. The influence of permeability on the trans-impedance is characterized by conductivity. Based on this, a temperature compensation method for ferromagnetic materials is developed. Then, a temperature influence experiment and a structural crack quantitative monitoring experiment are carried out using a front beam connection structure of an aircraft wing. The temperature effect experimental results show that even if the ambient temperature changes from 60 °C to −40 °C, the characteristic signal ΔC does not change significantly, indicating that the gasket has a temperature compensation capability. The experimental results of the crack monitoring of the front beam connection structure show that the gasket can bear the load and has the capability to quantitatively monitor cracks, and can be used for the quantitative monitoring of cracks in the critical connection structure of aircraft structures.

Nonlinear aeroelastic characteristics analysis of composite wing with high aspect ratio based on co-rotational method

A flexible high aspect ratio wing (HARW) generate large structural deformations. The nonlinear static aeroelastic and flutter characteristics analysis for the wing were performed using a nonlinear approach based on the computational fluid dynamic and computational structure dynamics (CFD/CSD) coupled method. The structural analysis was performed using a high efficiency nonlinear 4-node thin shell element based on the co-rotational (CR) method and the developed 4-node linear element to analyse large structural deformations. The load was calculated by the CFD solver. The result showed that the change of aerodynamic load led to a decrease of pressure difference between the upper and lower airfoils, especially the locations between the front and rear beams. At the attack angle of 6°and flight speed of 0.75 Ma, the maximum deflection and torsion angle of linear wing structure were approximately 13.27% and 32.38% greater than that of nonlinear wing structure, respectively. Because of the influence of nonlinear characteristic, the vertical and spanwise displacements and torsion angle of wing cross-sections were less than the linear result under the same flight attitude. The experimental results of the AGARD 445.6 wing verified the accuracy of the established flutter analysis method. The influence of the geometrical nonlinear characteristics of the structure caused by large deformation must be considered during the flutter characteristic analysis of the high aspect ratio composite wing, and the limit cycle oscillation (LCO) phenomenon cannot be obtained by the linear structure in the flutter analysis.