Maximum Acceleration Values Research Articles

MODIFICATION OF THE ATTENUATION EQUATION FOR PEAK GROUND ACCELERATION (PGA) IN THE NORTH SUMATERA REGION

Prediction of the empirical formula for ground acceleration is an important thing to analyze for seismic estimation in an area. This needs to be done to reduce the negative impact of earthquakes as a more appropriate mitigation effort in planning and designing earthquake-resistant buildings. Therefore, the empirical formulation from Zhaou, et al is used, which is well adapted to the seismotectonic conditions of the North Sumatra region, which has high seismic vulnerability, considering that this region is located in an active subduction zone. This advantage allows the model to more accurately predict the maximum ground acceleration (PGA) produced by earthquakes in the region. The purpose of this research is to obtain an empirical formulation of the maximum ground acceleration value based on seismic parameters such as distance, depth, and magnitude. It will also show the relationship between these parameters and the value of maximum ground acceleration or peak ground acceleration (PGA) in the North Sumatra region. This study modifies the empirical formulation of Zhao, et al data sourced from the Meteorology Climatology and Geophysics Agency (BMKG) of North Sumatra in 2017-2023 with a magnitude of 3 - 6 Mw. This research uses non-linear regression with the least squares method. The results of the analysis of the empirical formula produce the constant value sought a = 1.4703 b = -0.0025, c = 20.7441, d = 0.0196, e = 0.0015, S_SS = -2.0843, and S_SL = -0.0529. An empirical formula was obtained for the North Sumatra region based on the research results. This equation can be used on a scale of 3.0 - 6.0 Mw and a distance to the earthquake source between 0 - 300 km. The relationship between each parameter of this empirical formula is that the PGA value will increase with the magnitude, and the PGA value will decrease as the epicentre distance increases.

Effect of additively manufactured polymeric inserts on impact response of construction safety helmets

Purpose Struck-by accidents (i.e. being hit by a falling object) are a leading cause of traumatic brain injuries in the construction industry. Despite the critical role of hard hats in minimizing such injuries, their overall design has not appreciably changed in decades. Therefore, this study aims to explore the potential benefits of modifying commercially available hard hat designs by incorporating a compliant cantilever and a sacrificial, energy-absorbing structure to enhance their protective capabilities against impacts. Design/methodology/approach This study involved conducting experimental impact tests to obtain the head acceleration attenuation using hard hats with a variety of compliant cantilever lattice insert designs. These lattice inserts were additively manufactured using three polymeric materials, including polylactide (PLA), acrylonitrile butadiene styrene, high-impact polystyrene and three porosity levels. A Hybrid III head/neck assembly was fitted with each hard hat design, and experimental drop tests were conducted using a 1.8-kg steel impactor dropped from 1.83 m. The maximum acceleration and head injury criterion (HIC) values were obtained for each test. Findings Analysis of variance revealed that HIC was significantly reduced for all lattices with 56% porosity (p < 0.023) compared to the control (unmodified) hard hat. The most effective insert was found to be a PLA insert with 56% porosity, which reduced the HIC value by 38% compared to the control (unmodified) hard hat, with a statistically significant p-value of 0.018. Originality/value The data present in this study reveals that simple and inexpensive modifications can be made to existing hard hat designs to reduce injury risk from overhead impacts.

Determination of parameters generating the reference pressure in the primary level dynamic pressure measurement system based on the drop weight method

For some industries such as automotive, defence, aerospace, pharmaceutical manufacturing, dynamic pressure measurement is an important requirement. In a primary level dynamic pressure measurement system with a drop weight method, the dynamic pressure value is calculated using parameters such as the effective area value depending on the piston cylinder unit, the maximum acceleration value measured by a laser interferometer. On the other hand, the type of liquid used in the measuring head is another important factor affecting repeatability and providing ease of measurement. In this study, a new measurement head, piston and cylinders were designed, manufactured and the Taguchi method was used to accurately determine some parameters affecting the measurements in a dynamic primary pressure measurement system operating with the drop weight method. In the studies carried out, four pistons, four cylinders, four sampling frequency values and two liquid types were considered. By using the Taguchi method, the optimum parameters of the dynamic pressure measurement system with drop weight method were determined with only sixteen experiments instead of one hundred and twenty-eight.

Low-velocity impact behavior of two-way SFRC slabs strengthened with steel plate

Structural systems and structural elements can often suffer severe damage or even completely collapse under the effect of sudden dynamic impact loading, which is a different type of loading that is not considered during their design. Research on how structures behave under impact loading and how they can be strengthened to perform better against this type of loading has increased to avoid such undesirable severe damage. Within the scope of this study, it is aimed to improve the behavior and increase the performance of two-way steel fiber-reinforced concrete (SFRC) slabs, one of the leading structural elements that can be affected by impact loading, using steel fiber concrete (SFC) and placing steel plates on the surface of the RC slab. Within the scope of the study, the effects of placing FRC as layers in different positions within the slab and placing the steel plate on different surfaces of the slabs were examined. Impact loading was applied using a drop weight test setup designed by the authors, and the acceleration–time, displacement–time, and impact loading–time behaviors of the RC slabs were measured and interpreted. The use of fiber concrete in RC slabs and strengthened with steel plates increased the maximum acceleration values by an average of 3% and 113%, respectively. The use of fiber concrete in RC slabs reduced the maximum displacement and residual displacement values by an average of 2% and 25%, respectively. Placing steel plates on the slabs reduced the maximum displacement and residual displacement values by an average of 270% and 199%, respectively. In addition, the energy absorption capacities of RC slabs were calculated, and how they were affected by experimental variables was examined. Numerical analyses of the RC slabs tested in the study were also conducted using ABAQUS finite element software, and the results obtained were compared with the experimental ones.

Forced Vibration of Time-Varying Elevator Traction System

This paper proposes a theoretical model for the forced vibration of time-varying elevator traction systems caused by eccentric excitation of the traction machine. Based on the Hamilton principle and a variational principle with variable boundaries, the equations of motion and the complex boundary condition of a time-varying elevator traction system are established. A quantitative formula between the angular velocity of the traction machine, the diameter of the traction wheel, the elevator running distance and the running time is put forward. It is found that when the maximum values of acceleration and deceleration exceed 1.5 m/s², the elevator traction system may undergo resonance.

Novel dimensionless parameters in 2D wedge drop

ABSTRACT The aim of this research is to create new dimensionless relations in rigid wedge impact problems, which provides the possibility of calculating wedge kinematic parameters with acceptable accuracy. To accomplish this, the rigid wedge impact problem is simulated and validated using the Dynamic Fluid Body Interaction (DFBI) model in STAR-CCM+. In this study, new non-dimensional relations for the kinematical parameters of the wedge are derived utilising the Buckingham π theorem and data-driven analysis. It is observed that the use of appropriate dimensionless relations in any type of symmetric water impact problems involving a wedge shaped object will result in a unique diagram of each wedge kinematical parameter. This ultimately leads to the creation of two separate formulas to determine the maximum wedge acceleration value and its corresponding time. These formulas play a vital role in the design of high-speed crafts, and planing vessels.

Acceleration-Based Switching Surfaces for Impulsive Trajectory Design Between Cislunar Libration Point Orbits

A method is proposed to generate an initial guess for impulsive trajectory design in the circular restricted three-body problem. The method uses acceleration-based switching surfaces to obtain near-impulsive solutions. A numerical continuation is performed on the maximum acceleration value to find near-impulsive solutions. A nonlinear programming problem is formulated by providing primer vector based analytical gradients. The solution space is narrowed down to aid the optimizer with the use of the near-impulsive solutions. The proposed method is used for the trajectory design of four different maneuvers between L1 and L2 Halo orbits in the Earth–Moon system. The results demonstrate the utility of the proposed method in generating extremal impulsive trajectories.

Identifying Risk Factors for Preexisting or Developing Low Back Pain in Youth, High School, and Collegiate Lacrosse Players Using 3-Dimensional Motion Analysis.

Low back pain (LBP) is a common condition that can affect athletes of all ages. The risk factors for LBP onset and worsening associated with the lacrosse shooting motion are not yet known. To identify training and biomechanical factors associated with preexisting LBP and development of LBP over 6 months in youth, high school, and collegiate lacrosse players. Case-control study; Level of evidence, 3. A total of 128 lacrosse players were enrolled in this study between January 2016 and January 2019. Player characteristics, lacrosse experience, and participation in other sports were self-reported. At baseline and 2-, 4-, and 6-month follow-ups, the players self-rated the presence and severity of LBP using a numeric pain rating scale (0-10 points). Participants were grouped according to LBP symptoms: no LBP at any time point (n = 102), preexisting LBP (n = 17), or developed LBP within the 6-month period (n = 9). The lacrosse shooting motion was captured via 3-dimensional motion analysis, and kinematic and kinetic variables were recorded. A Low Back Stress Index was used to estimate lumbar stress as a function of pelvic acceleration at the time of maximum lateral trunk lean during the shot. Univariate analyses of covariance and logistic regression models were used to address study aims. Compared with the no-LBP group, the preexisting LBP group demonstrated 13.9% to 22.9% lower maximum angular velocities at the pelvis, trunk, and shoulders in the transverse plane (P < .05), 19.3% less collective pelvis-shoulder rotation in the transverse plane (P = .015), and 4.5% more knee flexion excursion (P = .063). The developed-LBP group produced 2.3% to 11.1% higher angular velocities in the pelvis, trunk, and shoulder and generated maximum pelvic acceleration values 36% to 42% higher than the remaining groups (P < .05 for both). Mean Low Back Stress Index values were not statistically significant among the groups (no LBP: 12,504 ± 13,076 deg2/s2; preexisting LBP: 8808 ± 10,174 deg2/s2; developed LBP: 19,389 ± 13,590 deg2/s2; P = .157). Preexisting LBP was associated with significantly restricted motion of the pelvis, trunk, and shoulders during a lacrosse shot. Excessive pelvic acceleration may be related to the development of LBP in lacrosse players.

A novel multi-resonator honeycomb metamaterial with enhanced impact mitigation

Local resonant metamaterials show significant promise in applications involving the attenuation of impact waves. This paper introduces a honeycomb metamaterial featuring a circular distribution of multiple mass-beam resonators designed to enhance impact mitigation by broadening low frequency bandgaps. The bandgaps of unit cells with different number of mass-beam resonators (MBR) are calculated. It is found that the unit cell with circularly distributed resonators (C-MBR) has strong low frequency local resonance in all directions, thus opening a complete wide bandgap in about 500–1200Hz. Then, a method of equivalent stiffness reduction related to the corresponding mode shapes is used to research the negative effective mass density characteristic, explaining the generation of the low frequency bandgaps. Subsequently, the impact protection capacity of local resonant metamaterial is compared with that of ordinary honeycomb metamaterial through experiment and simulation. Interestingly, the maximum acceleration values under the impact load of local resonant metamaterial are about 45% lower than that of honeycomb metamaterial, and the reaction force under the blast load is about 80% reduction. Besides, by analyzing the acceleration curve waveform and transmission spectrum, the local resonant metamaterial is found to exhibit continuous short period vibration, which blocks the wave in low frequency band. Finally, the energy dissipation performance of the local resonant metamaterial explains that it converts more impact energy into the kinetic energy of the core with resonators, thereby reducing the energy transferred to the bottom panel. These results underscore the potential application of the proposed metamaterial with multi-resonators in impact mitigation and energy dissipation.

Design and Realization of Landing–Moving Integrated Gear for Mobile Lunar Lander

For the needs of manned landing, station construction, and material transfer in future lunar exploration missions, the paper proposes a landing–moving integrated gear (LMIG) for mobile lunar lander (MLL), establishes and optimizes the models of cushioning energy-absorbing and movement planning, respectively, and conducts the prototype tests. First, the design requirements of LMIG are given, and the system composition of LMIG and the configuration design of each subsystem are introduced. Second, the effective energy-absorbing model of the aluminum honeycomb is established and experimentally verified, a three-stage aluminum honeycomb buffer is designed and experimentally verified, and the buffer mechanism of LMIG is verified by simulations under various landing conditions. Furthermore, the kinematic and dynamic models of LMIG are established, the moving gait is designed by the center of gravity trajectory planning method, and the driving trajectory during the stepping process is optimized with the goal of minimal jerk of motion. Finally, a cushioning test prototype and a walking test scaled prototype of LMIG are developed, and single leg drop test and ground walking test are carried out. The results show that the established model of LMIG is reasonable, the designed buffer and gait of LMIG are effective, the developed prototypes of LMIG have good cushioning and movement performance, the LMIG’s maximum value of overload acceleration is 6.5 g , and the moving speed is 108 m/h, which meets the design requirements.

Effect of Different Scaling Methods on Seismic Isolator Behavior

This study investigated the maximum displacement, force, and acceleration values occurring at the isolation level in structures with lead rubber bearings using nonlinear response history analyses. Earthquake records used in the dynamic analysis were scaled with four different methods. In order to perform bi-directional analysis, both horizontal components of the earthquake records were applied to the isolation units simultaneously. In the analysis, the loss of strength (deterioration) due to the heating in the lead core due to the cyclical motion has been considered. In addition, in seismic isolated structures, five periods (Tiso=2.5s, 2.75s, 3.0s, 3.25s, and 3.5s) representing the isolation period, and four characteristic strength ratios (Q/W=0.75, 0.90, 0.105 and 0.120) representing the strength of the isolation unit were taken into account. As a result of the study, 10-13% change was observed in the maximum acceleration and displacement values at the isolation level due to different scaling methods. In addition, there was a 3% change in force results, and no significant difference occurred.

Modeling and Machine Learning of Vibration Amplitude and Surface Roughness after Waterjet Cutting.

This study focused on analyzing vibrations during waterjet cutting with variable technological parameters (speed, vfi; and pressure, pi), using a three-axis accelerometer from SEQUOIA for three different materials: aluminum alloy, titanium alloy, and steel. Difficult-to-machine materials often require specialized tools and machinery for machining; however, waterjet cutting offers an alternative. Vibrations during this process can affect the quality of cutting edges and surfaces. Surface roughness was measured by contact methods after waterjet cutting. A machine learning (ML) model was developed using the obtained maximum acceleration values and surface roughness parameters (Ra, Rz, and RSm). In this study, five different models were adopted. Due to the characteristics of the data, five regression methods were selected: Random Forest Regressor, Linear Regression, Gradient Boosting Regressor, LGBM Regressor, and XGBRF Regressor. The maximum vibration amplitude reached the lowest acceleration value for aluminum alloy (not exceeding 5 m/s2), indicating its susceptibility to cutting while maintaining a high surface quality. However, significantly higher acceleration amplitudes (up to 60 m/s2) were registered for steel and titanium alloy in all process zones. The predicted roughness parameters were determined from the developed models using second-degree regression equations. The prediction of vibration parameters and surface quality estimators after waterjet cutting can be a useful tool that for allows for the selection of the optimal abrasive waterjet machining (AWJM) technological parameters.

Analysis of the Dynamic Cushioning Property of Expanded Polyethylene Based on the Stress-Energy Method.

This paper aimed to experimentally clarify the dynamic crushing performance of expanded polyethylene (EPE) and analyze the influence of thickness and dropping height on its mechanical behavior based on the stress-energy method. Hence, a series of impact tests are carried out on EPE foams with different thicknesses and dropping heights. The maximum acceleration, static stress, dynamic stress and dynamic energy of EPE specimens are obtained through a dynamic impact test. Then, according to the principle of the stress-energy method, the functional relationship between dynamic stress and dynamic energy is obtained through exponential fitting and polynomial fitting, and the cushion material constants a, b and c are determined. The maximum acceleration-static stress curves of any thickness and dropping height can be further fitted. By the equipartition energy domain method, the range of static stress can be expanded, which is very fast and convenient. When analyzing the influence of thickness and dropping height on the dynamic cushioning performance curves of EPE, it is found that at the same drop height, with the increase of thickness, the opening of the curve gradually becomes larger. The minimum point on the maximum acceleration-static stress curve also decreases with the increase of the thickness. When the dropping height is 400 mm, compared to foam with a thickness of 60 mm, the tested maximum acceleration value of the lowest point of the specimen with a thickness of 40 mm increased by 45.3%, and the static stress is both 5.5 kPa. When the thickness of the specimen is 50 mm, compared to the dropping height of 300 mm, the tested maximum acceleration value of the lowest point of the specimen with a dropping height of 600 mm increased by 93.3%. Therefore, the dynamic cushioning performance curve of EPE foams can be quickly obtained by the stress-energy method when the precision requirement is not high, which provides a theoretical basis for the design of cushion packaging.

Predicting Models for Local Sedimentary Basin Effect Using a Convolutional Neural Network

Although the numerical models can estimate the significant influence of local site conditions on the seismic propagation characteristics near the surface in many studies, they cannot feasibly predict the seismic ground motion amplification in regular engineering practice or earthquake hazard assessment due to the high computational cost and their complex implementation. In this paper, the scattering problem of trapezoidal sedimentary basins, one of the representatives of local complex sites with a relatively small model size, and simplified by practice in this type of study, was selected as the basin model. A series of standard basin models were built to quantify the relationship between the site condition parameters and the site amplification parameters (the peak ground acceleration and the hazard location). In addition, the factors that influence seismic ground motion amplification, such as the basin shape ratio, the soil depth, the basin edge dip angle, the ratio of shear wave velocity between the bedrock and the soil layer, the damping coefficient, and the fundamental frequency, were selected to investigate the sensitivity. A convolutional neural network (CNN) algorithm based on deep learning replacing traditional recursive algorithms was explored to establish a prediction model of basin amplification characteristics. By the Bayesian optimization method, the structural parameters of the CNN predicting model were selected to improve the accuracy of the prediction model. The results show that the optimized CNN models could predict the amplification characteristics of the basin better than the un-optimized CNN models. Three prediction models were established with the site condition parameters as the input parameters and their output parameters were the maximum amplification value of the peak ground acceleration (PGA), the hazard location, and their combination for each basin. To analyze the CNN’s prediction ability, each CNN model used about 80% of the data from the seismic model repose results for training and the remaining data (20%) for testing. By comparing the CNN prediction results with the FE simulation results, the accuracy and rationality of each prediction model were studied. The results show that, compared to a single numerical model, the CNN prediction results of the site amplification features could be quickly obtained by inputting the relevant parameters. Compared to recursive class models, the established CNN prediction model can directly establish the relationships among multiple input and multiple output parameters. A comparison of the three kinds of CNN models shows that the prediction accuracy of the joint parameter model was slightly lower than that of the two single-output models.

Design, fabrication, and experimental study of a full-scale compressed air ejection system based on missile acceleration limitation

In this paper, we study the interior ballistic characteristics of rockets or missiles with acceleration less than 10 g during the compressed air ejection process. First, we designed and fabricated a full-size compressed air ejection system, and utilizing different missile mass and initial pressure variables. Then, we established the mathematical model of the interior ballistics of the ejection system using the fourth-order Runge-Kutta scheme to estimate the ejection performance and results of the system. In addition, we independently built a full-scale compressed air ejection system test platform and conducted multi-condition live ejection tests. The results show that the effective travel distance of the missile is greater than 2.5 m and the acceleration is basically less than 10 g. With a certain missile mass, the acceleration peak, velocity peak and displacement of the missile are positively correlated with the initial pressure, and the opposite variable is negatively correlated. The maximum acceleration and velocity values are 10.11 g and 13.5 m/s, respectively, and the minimum values are about 3.5 g and 4 m/s. The variables are the same, the pressure peak at each measuring point in the ejection barrel is bottom > middle > upper, and the amplitude of the pressure drop between middle and bottom gradually decreases. Depending on the appearance time of the pressure point, the maximum pressure attenuation time in the ejection barrel is determined to be 0.838 s, and the minimum is 0.343 s. Comparing the pressure peak points at the bottom, middle and upper with the calculated pressure curve, the attenuation trend of the two is basically the same. Therefore, the research results show that the full-scale compressed air ejection system is effective and practical, and the test results provide data reference for related launches.

An Air-Filled Bicycle Helmet for Mitigating Traumatic Brain Injury.

We created a novel air-filled bicycle helmet. The aims of this study were (i) to assess the head injury mitigation performance of the proposed helmet and (ii) to compare those performance results against the performance results of an expanded polystyrene (EPS) traditional bicycle helmet. Two bicycle helmet types were subjected to impacts in guided vertical drop tests onto a flat anvil: EPS helmets and air-filled helmets (Bumpair). The maximum acceleration value recorded during the test on the Bumpair helmet was 86.76 ± 3.06 g, while the acceleration during the first shock on the traditional helmets reached 207.85 ± 5.55 g (p < 0.001). For the traditional helmets, the acceleration increased steadily over the number of shocks. There was a strong correlation between the number of impacts and the response of the traditional helmet (cor = 0.94; p < 0.001), while the Bumpair helmets showed a less significant dependence over time (cor = 0.36; p = 0.048), meaning previous impacts had a lower consequence. The air-filled helmet significantly reduced the maximal linear acceleration when compared to an EPS traditional helmet, showing improvements in impact energy mitigation, as well as in resistance to repeated impacts. This novel helmet concept could improve head injury mitigation in cyclists.

Multi System Level Driving Scenarious Based Topology Optimization of Bracket Design for 2 DoF Vehicle Simulator

This article presents a topology optimization of the motor mounting bracket in a 2-degree-of-freedom (2 DoF) vehicle simulator that is enhanced by the driving scenari-os. Firstly, a 14 DoF passenger reference application model is determined in the Sim-ulink environment. Then, common driving scenarios (Constant Radius, Double Lane Change, Fishhook, Increasing Steer, Sine with Dwell and Swept Sine) are run on 14 DoF vehicle models to test the dynamic performance of the vehicle. During the anal-ysis, accelerations in the XYZ axes are logged, and the minimum and maximum ac-celeration values on each axis are grouped separately for each driving scenario. Next, the concept design of 2 DoF vehicle simulators is created. The obtained accelerations from the driving scenarios are then run on 2 DoF vehicle simulator in the Solidworks simulation environment, and stress and deformation on the 2 DoF vehicle simulator are analyzed. During this analysis, linear actuator and axis forces are calculated ac-cording to the reaction forces on the vehicle simulator. Under the determined axial forces, the brackets are subjected to topology optimization. The obtained generative design of the bracket is reshaped by post-processing for sustainable production. The shape-optimized bracket is run again on the 2 DoF vehicle simulator with the ob-tained acceleration values from the driving scenarios, and the study is completed by performing stress and deformation analysis.

Simulation Analysis and Online Monitoring of Suspension Frame of Maglev Train

A maglev train is a new type of high-speed railway transportation. A high-temperature superconducting (HTS) maglev system is one of the typical representatives in the field of maglev trains. In order to research the levitation characteristics of an HTS maglev train, the force characteristics and operation performance of the train were researched. However, at present, there is still no research that simulates the real load situation of a running maglev train while analyzing the suspension frame. Regarding this issue, in this paper, the suspension frame is simulated and analyzed to simulate the real load situation of a maglev train. The results show that the suspension frame of an HTS maglev train can bear corresponding loads under different working conditions, and its strength and stiffness meet the requirements of use, safety, and reliability. Random irregularity in the permanent magnet track of an HTS maglev train route is inevitable, which will make the suspension frame produce a vibration response under different running speeds of the train. Vibration of the suspension frame of the train is inevitable. For the electromagnetic levitation (EMS) train, researchers considered monitoring the train status. However, at present, there is no suspension frame condition monitoring device for an HTS maglev train. In addition, the levitation height of the suspension frame affects the suspension performance and traction performance of the vehicle, and the vibration of the suspension frame during running affects the dynamic performance and safety of the suspension frame and the vehicle. Regarding the issue above, through a suspension frame monitoring system, the lateral and vertical vibration acceleration and levitation height of the suspension frame are monitored at different train speeds. The maximum value of vibration acceleration and the fluctuation range of levitation height are within the safe range. It is verified that the simulation analysis of the suspension frame of an HTS maglev train is correct, the suspension frame is safe, and the train can run safely.

Comparative Study of Intze Type of Water Tank for Different Bracing Pattern under Wind and Seismic Load

Abstract Overhead water tank is a water storage facility supported by a tower and constructed at an elevation to provide useful storage and pressure for a water distribution system. Safety as well as working of such structures is considered as very crucial during earthquakes, since they put up for necessities like drinking water, firefighting during fire accidents, etc. Such structures should stay in operating condition even after several earthquakes. This RC overhead water tanks involves huge water mass supported on the top of tank supporting system known as staging. This investigation is basically to discover the seismic behavior of RC overhead water tanks. In this study, a FEM based model is used for finding out the nonlinear seismic performance of RC overhead water tanks with several staging variations. The staging that is different bracing patterns considered in this study in lateral and vertical direction, which relatively increases the strength and stiffness of tank in supporting system. Staad models are prepared and analyze for different seismic zones as well as for cyclonic regions and observed the parameters such as base shear, base moment and lateral displacement. The commercial software STAAD.Pro is used for structural analysis. Since the seismic response of water tank structure depends on its dynamic properties and frequency of ground motion. This seismic analysis of overhead water tank structure cannot be carried out on the basis of maximum value of ground acceleration because of nonavailability of ground acceleration data at every location. Hence for seismic analysis of overhead water tank, earthquake response spectrum analysis is widely used. While using this method, smooth design spectra is used to determine the value of displacement and forces in members at every mode of vibration. Octagonal, Radial, Cross, Alternate tie , Diagonal and X- type bracings are used to analyze the structure under all the seismic zones viz. II, III, IV &amp; V. Also observed the behavior of tank for cyclonic region where wind load is increased by 30%. Analysed the overhead water tanks of same capacity for different bottom dome deviation angles and concluded.

THE SIGNIFICANCE OF DYNAMIC FORCES ACTING ON A GONDOLA CAR WHEN UNLOADING BY A ROTARY CAR DUMPER

The article considers the factors influencing the strength of gondola cars during unloading on rotary car dumpers, before which a preliminary careful analysis of their characteristic damage and malfunctions was carried out. The calculated schemes of the system design are constructed and the analytical determination of the inertial components of the dynamic overturning process is performed. Initial recommendations for the design of the body structure, which is exposed to high dynamic loads during the mandatory unloading of the freight vehicle. The issue of fleet conservation is important for owners and operators of rolling stock, based on the balance of working and non-working fleet. The main cause of damage to the load-bearing structure of the gondola is non-compliance with the content of regulatory documents when performing loading and unloading operations. Unloading of gondola cars in the method of overturning was introduced at industrial enterprises in the last century during the intensive industrialization of the German experience and supply of equipment and is now successfully carried out using special technical devices - stationary rotor tippers. According to the results: acceleration of the PV body occurs at an angle of rotation of about 60°; the maximum values of accelerations are observed at an angle of rotation of 125°. This is done at the final stage of the flow of the load, because the final component of the full angle of rotation no longer affects the dynamics, because the load in the body is not a large part. The results of theoretical research at the design stage of the PV allow to take into account possible dynamic factors due to the overturning of the PV body, and prevent probable damage, assess the margin of safety and reliability of the body structure, which will ultimately reduce maintenance costs and increase life cycle load.