Calculation Of Load Distribution Research Articles

Dynamic Analysis of Helical Gears Considering Friction

The use of high contact ratio (HCR) gears is an effective method to reduce single tooth loads, as well as vibration and noise, making the application of helical gears increasingly widespread. Although the presence of helix angles can cause significant relative sliding, the presence of more teeth in contact makes HCR gears more sensitive to surface quality. The existing literature mainly investigates geometric optimization, load distribution, or efficiency calculation of helical gears. The research on the influence of rough surfaces on the dynamic performance of helical gears is very limited. To this end, a multi degree of freedom mathematical model of static transmission error was established based on the 2-DOF system. The relative sliding friction was studied using different friction coefficients, and the influence of different friction coefficients on the gear system was analyzed in detail. The numerical results indicate that surface roughness has a relatively small impact on the dynamic transmission error of the system, but has a significant impact on the motion and friction in the direction of departure.

Multi-objective optimization and accelerated experimental research on load distribution of planetary roller screw mechanism

Load distribution is a critical characteristic that determines the load carrying capacity of planetary roller screw mechanism (PRSM). First, a load distribution calculation model is established. Subsequently, a multi-objective optimization model to achieve uniform load distribution is constructed based on NSGA-II. Then, considering the optimization effect, machining feasibility and machining efficiency, the optimal load uniform distribution design method for linear thinning of thread thickness is determined using the analytical hierarchy process. Finally, an accelerated test method of PRSM load-bearing characteristics based on abrasive technology is proposed for the first time. The experimental results show that after optimization, the maximum contact width decreases by 12.5% and the fluctuation amplitude decreases by 74.6%, which significantly improves the uniformity of PRSM load distribution.

A practical approach of partial striking technique in high-rise buildings

PurposeThis research proposes a viable method of slab and shore load computation for the partial striking technique utilized in high-rise construction projects to optimize the use of horizontal formwork. The proposed Partial Striking Simplified Method (PSSM) is designed to be utilized by industry practitioners to schedule the construction operations of casting floors in order to control the formwork costs incurred throughout the completion of a project.Design/methodology/approachThe article presents the PSSM for calculating slab and shore loads in multi-story building construction. It introduces the concept of “clearing before striking,” where shore supports are partially removed after a few days of pouring fresh concrete. The PSSM procedure is validated through numerical analysis and compared to other simplified approaches. Additionally, a user-friendly Python program based on the PSSM procedure is developed to explore the capability of the PSSM procedure and is used to study the variations in slab load, shoring level, concrete grade and cycle time.FindingsThe study successfully developed a more efficient and reliable method for estimating the loads on shores and slabs using partial striking techniques for multi-story building construction. Compared to other simplified approaches, the PSSM procedure is simpler and more precise, as demonstrated through numerical analysis. The mean of shore and slab load ratios are 1.08 and 1.07, respectively, which seems to have a slight standard deviation of 0.29 and 0.21 with 3D numerical analysis. The Python program developed for load estimation is effective in exploring the capability of the proposed PSSM procedure. The Python program's ability to identify the floor under maximum load and determine the specific construction stage provides valuable insights for multi-story construction, enabling informed decision-making and optimization of construction methods.Practical implicationsHigh-rise construction in Indian cities is booming, though this trend is not shared by all the country's major metropolitan areas. The growing construction sector in urban cities demands rapid construction for efficient utilization of formwork to control the construction costs of project. The proposed procedure is the best option to optimize the formwork construction cost, construction cycle time, the suitable formwork system with optimum cost, concrete grade for the adopted level of shoring in partaking and many more.Originality/valueThe proposed PSSM reduces the calculation complexity of the existing simplified method. This is done by considering the identical slab stiffness and identical shore layout for uniform load distribution throughout the structure. This procedure utilizes a two-step load distribution calculation for clearing phase. Initially, the 66% prop load of highest floor level is distributed uniformly over the lower interconnected slabs. In the second step, the total prop load is removed equally from all slabs below it. This makes the load distribution user-friendly for the industry expert.

OPTIMALISASI DESAIN TRUK JUNGKIT CATERPILLAR 777D UNTUK PENGANGKUTAN BATU BARA

In the world of coal mining the use of heavy equipment is absolute. The use of heavy equipment in coal mining is a job that requires optimal production capabilities of heavy equipment, because there are large volumes of excavation work, stockpiling and transportation of material. The standard body design on the Caterpillar 777D dump truck has not been specifically designed for transporting coal materials, so it is not ideal. This study aims to design a dump truck body by adding a larger body capacity than the standard body. The standard used for determining the mass of material to be transported is in accordance with ISO 6483: 1980. After obtaining a new body design using Autodesk Inventor software, the weight of the body and the weight of the coal to be transported will be known, after that the load distribution calculation on the axles will be carried out. front and rear axles. Load distribution will be limited by the maximum load allowed on the front axle and rear axle according to the regulations specified on the Caterpillar 777D unit. Having obtained a new body design with a more optimal transport volume capacity, it will be very useful for more efficient coal transportation. So it was concluded that the results of the analysis of the Caterpillar 777D tub specifically for coal transportation can exceed the standard volume capacity with a volume capacity of 120 m3.

Evaluation of the load distribution of timber slab bridge and the efficiency of the retrofit methods

Timber slab bridges are commonly used in rural regions because of their simple construction and low costs. However, a review of the bridge manual indicates that there is no specific guidance or very similar guidance to the current nationwide bridge codes with respect to the calculation of wheel load distribution and strengthening/enhancing methods. The objective of this research is to evaluate the load distribution for timber slab bridges and the efficiency of the retrofit methods. To achieve this objective, ten timber slab bridges were identified for a program of bridge live load tests. Three of them were tested twice, once before and once after bridge strengthening measures were employed. The data collected from the field test program was utilized to calculate the equivalent strip width (ESW), and the results were compared with the codified values. In addition, a series of finite element (FE) models were created based on these ten field-tested bridges and validated against the field-collected data. The validated FE models were utilized for a parametric study to evaluate the wheel load distribution and the performance of various retrofit methods on the bridges with different truck loading, bridge geometry, and retrofit approaches. Based on the results from the field tests and analytical simulation, an equation to predict the equivalent strip width for the timber slab bridges was developed with consideration of numerous variables.

Enhanced loaded tooth contact analysis of hypoid gears within a multi-body-system simulation

To calculate the load capacity of gear stages within complex drivetrains under varying external loads, multi-body-systems (MBS) are used to simulate the vibrational behaviour of integral systems. In order to model a flexible hypoid gear stage, methods like the modal reduction of FEM-models were already introduced. However, the modelling of such systems is complex, challenging and sensitive to its discretisation. The co-simulation within a multi-body-system simulation offers the possibility to outsource the calculation of the tooth contact and therefore the reaction forces under consideration of friction. This leads to a simplification and an improvement of the modelling of gear stages in multi-body-systems.The further developed co-simulation module offers a compromise between computational speeds and exact solutions. To improve the quality of the results and reduce the calculation time the load distribution calculation is investigated specifically. The article describes a method to reduce fluctuations of computed reaction forces and moments during gear movement. The aim is to keep the level of fluctuations of a high contact zone discretisation with a significant smaller contact point count.

An Improved Differential Evolution Whale Algorithm for Economic Load Distribution

An improved optimization algorithm combining the differential evolution algorithm and the whale algorithm is proposed for the problem of not being able to get rid of the local optimum in the economic load distribution algorithm. The algorithm adopts a nonlinear convergence strategy, a crossover strategy of differential evolution and the introduction of an elimination mechanism, which balances the global search and local exploitation ability of the algorithm and improves the accuracy of the solved optimal solution. The 13-unit and 40-unit systems are selected for economic load distribution calculation, and the experimental results show that the proposed improved algorithm is superior in distributing the economic load of the power system and can effectively reduce the economic cost.

Research on Online Mathematical Models of Tandem Cold Rolling

The tandem cold rolling process control system is an important part of the computer control system of the tandem cold mill coupled pickling line, and it is an important means to ensure the output and quality of cold rolled strip. On-line mathematical models of tandem cold rolling are the premise of formulating rolling rules, setting of rolling mill parameters and calculation of load distribution. They calculate the set values and rolling parameters required by the automation system based on the rolled piece and equipment parameters. Therefore, it is of great practical significance to study the on-line mathematical models of tandem cold rolling and to establish a model of high precision and high value-added products.

Scheming an Proficient Auto Scaling Technique for Minimizing Response Time in Load Balancing on Amazon AWS Cloud

Cloud computing is one of the developing innovation in the field of data improvement. Because of its huge application, for example, virtualization and dynamic asset portion, the cloud computing ends up being the most encouraging innovation. To give the solid support of the customers with Quality of Service (QOS), the load balancing component with auto scaling methods would be vital in cloud computing conditions. With the end goal to keep the framework from overloading and slamming, a productive calculation must be given by the application and approaching client activity in the cloud computing condition. The proposed Auto Load Distribution (ALD) calculation have been assessed and contrasted and some of existing load balancing algorithm and its effectiveness is vastly improved than the past calculations. To accomplish the previously mentioned issues, we tried our undertakings in Amazon EC2 stage, one of open cloud administrations which give correct qualities. Results have been investigated and limiting the reaction time greater by utilization of auto scaling system through our proposed ALD algorithm.

Construction of a model for the distribution of radial load among the bearing's rolling bodies

We have proposed analytical and computer models related to the distribution of radial load among the rolling bodies in a single-row radial bearing.We have analyzed patternsin the geometry and deformation of parts, as well as gaps in the bearing without taking into consideration the different positions of centers of the inner and outer rings. The latter can significantly affect the distribution of radial load among rolling bodies and cause the slippage of rolling bodies on rings. The present study aims to refine the estimated value of load distribution among the bearing's rolling bodies. The closer the result of calculation of load distribution, especially, on the central rolling body, to the actual value, the more accurately the resourceis determined. That largely defines the reliability of a machine, as well as the cost of repair and replacement of bearings. It is equally important when determining the fatigue strength and durability of the separator to know as accurately as possible the magnitudes and directions of action of radial forces on the rolling bodies at the edges of the bearing's loading zone. It is these forces that determine the loads acting on the separator. We have constructed geometrical equations that link the radial encounters of rings, physical equations that relate the encounters of rings and rolling bodies to forces, a condition for equilibrium of the inner ring taking into consideration the different positions of centers of the outer and inner rings of the bearing. We have identified tangential forces along the rings'rolling tracks, which cause the slippage of rolling bodies in the bearing's loading zone;a formula for determining their values has been derived. The calculation of distribution of load among thebearing's rolling bodies based on the constructed analytical model demonstrates a 5 % decrease in radial forces that act on the central rolling body, and a 3 % increase in radial forces that act on rollers at the edges of thebearing's loading zone compared to known model. That improves the estimated resource of the bearing in terms of contact-fatigue damage to rings and rolling bodies by 18.6 %. The new analytical model for the distribution of radial load could be applied in the theory of calculation of resource for bearings ofincreased lift capacityin terms of contact-fatigue damage to rings and rolling bodies considering the structure of the separator

Load distribution analysis in hull and turret interface bearing of armoured fighting vehicles

There are simple and well established formulae and data sheets for load calculations and design of uniaxial and biaxial loaded bearings. The load calculations and bearing design are complex and challenging, when the bearing is subjected to multi-axial loads along with moment and shock load. In case of Armoured Fighting Vehicles, the hull & turret interface bearing is subjected to combined heavy axial, radial load coupled with heavy shock load and tilting moments. This may cause significant changes in bearing deflections, contact stress and fatigue endurance compared to simpler load distributions. The empirical formulae for calculation of load distribution on each rolling element lead to indeterminate equations with many unknown variables. In the present study, a comprehensive procedure for determining the loading pattern and also numerical estimation of maximum load, maximum contact stress and the load distribution on each rolling element of the bearing are analysed.

Modelling and simulation of the load in the epicyclic rotary pump with trochoidal gear profiles

This paper presents an analysis of the load distribution in the trochoid pump with the planetary movement of the impeller. There are a lot of theoretical and numerical analyses conducted for the gerotor of the pump with fixed positions of the gear axis. Design of planetary gerotor pump has a different load distribution than gerotor with fixed axes. A planetary gerotor consists of a fixed outer gerotor gear with internal gearing and inner gear with an external gearing. The centre axis of the inner gear has a circular motion around the central axis of the fixed gear, because of the eccentricity on drive shaft. The special shape of the gerotor teeth forms chambers with varying volume that allows the flow and pressure of the fluid. During the pump working process the forces of different direction and intensity are present in each of the working chambers. It is necessary to determine the pressure in each of the chambers in order to obtain the load model of the gerotor. Load model will enable the calculation of load distribution in the zone of the maximum contact stresses. This calculation should help in dimensioning of the pump and the achievement of better performance characteristics.

Theoretical and experimental study on load sharing of a novel power split spiral bevel gear transmission

A load sharing analysis methodology is proposed for a new type of power split spiral bevel gearing system based on the closed-loop characteristic of the power flow. First, the mechanical structure model and the moment equilibrium equations of the system are constructed, and then the deformation compatibility equations describing the relationship between the moment and the normal deformation of tooth surface are derived. Second, an accurate model for load sharing calculation of a one-input-two-output working condition is proposed, and a general formula for the simplified engineering load distribution calculation is derived. Finally, an experiment is designed to demonstrate the feasibility of this method. It is found that the measured tooth root strain ratio of the 1–2 and the 1–4 branches coincides with the theoretical analysis results. The proposed analysis and experimental method provides a new approach for analyzing the load distribution of the power split gear transmission with a closed-loop power flow.

Load Distribution Calculation of a four-Point-Contact Slewing Bearing and its Experimental Verification

Analysis of the load distribution along raceways is fundamental for assessing dynamic and static capacity of the slewing bearings. In the literature, several finite element (FE) models have been proposed to estimate the load distribution and the deformation of slewing bearing. Although FE simulations are a useful tool for designers, there are a few experimental studies assessing accuracy and reliability of computations. In this paper, a FE model for a single-row four-point-contact slewing bearing is built in ABAQUS software. The key to the method is to simulate the balls under compression by traction-only nonlinear springs. Subsequently, the static loading experiment is designed: strain gauges are mounted on the inside circumference of the inner ring to obtain load distribution. The comparison between numerical and experimental results is discussed in detail. Remarkably, FE results are consistent with experimental data.

Calculation of radial load distribution on ball and roller bearings with positive, negative and zero clearance

The load distribution on rolling elements is one of the most important operating characteristics of a bearing. In this paper, a mathematical model for the calculation of radial load distribution on ball and roller bearings with positive, negative and zero clearance is derived and presented. A predeformation model for bearings with nonzero clearance is proposed. Based on contact deformation and Hertz elastic contact theory, inner raceway contact force is calculated and is used for static equilibrium equation, which could avoid calculate the series of stiffness of inner and outer raceway contact deformation. The static equilibrium equation is solved by a loop which aims to delete inactive rolling elements. The obtained results are compared with results of Harris and Stribeck method and found to be in close or identical agreement.

Research on the dynamic response of high-contact-ratio spur gears influenced by surface roughness under EHL condition

Employing high-contact-ratio (HCR) gear is an effective method of decreasing the load on a single tooth, as well as reducing vibration and noise. While the spindlier tooth leads to greater relative sliding, having more teeth participate in contact at the same time makes the HCR gear more sensitive to the surface quality. Available literature regarding HCR gear primarily investigates the geometrical optimization, load distribution, or efficiency calculation. Limited work has been conducted on the effect of rough surfaces on the dynamic performance of HCR gear. For this reason, a multi-degree-of-freedom (MDOF) model is presented mathematically to characterize the static transmission error based on fractal theory, investigate the relative sliding friction using an EHL-based friction coefficient formula, and detail the time-varying friction coefficient suitable for HCR gear. Based on numerical results, the surface roughness has little influence on system response in terms of the dynamic transmission error but has a large effect on the motion in off-line-of-action (OLOA) direction and friction force. The impact of shaft-bearing stiffness and damping ratio is also explored with results revealing that a greater shaft-bearing stiffness is beneficial in obtaining a more stable motion in OLOA direction, and a larger damping ratio results in a smaller effective friction force. The theory presented in this report outlines a new method of analyzing the dynamics of HCR gear in respect of introducing surface roughness into MDOF model directly, as well as establishing an indirect relationship between dynamic responses and surface roughness. This method is expected to guide surface roughness design and manufacturing in the future.

Optimal Machine-Tool Settings for the Manufacture of Face-Hobbed Spiral Bevel Gears

In this study, an optimization methodology is proposed to systematically define the optimal head-cutter geometry and machine-tool settings to simultaneously minimize the tooth contact pressure and angular displacement error of the driven gear (the transmission error), and to reduce the sensitivity of face-hobbed spiral bevel gears to the misalignments. The proposed optimization procedure relies heavily on the loaded tooth contact analysis for the prediction of tooth contact pressure distribution and transmission errors influenced by the misalignments inherent in the gear pair. The load distribution and transmission error calculation method employed in this study were developed by the author of this paper. The targeted optimization problem is a nonlinear constrained optimization problem, belonging to the framework of nonlinear programming. In addition, the objective function and the constraints are not available analytically, but they are computable, i.e., they exist numerically through the loaded tooth contact analysis. For these reasons, a nonderivative method is selected to solve this particular optimization problem. That is the reason that the core algorithm of the proposed nonlinear programming procedure is based on a direct search method. The Hooke and Jeeves pattern search method is applied. The effectiveness of this optimization was demonstrated on a face-hobbed spiral bevel gear example. Drastic reductions in the maximum tooth contact pressure (62%) and in the transmission errors (70%) were obtained.

Load Distribution of Cross-Roller Slewing Bearing

Because of cross roller-slewing bearing structure have a certain degree of particularity, and two sets of cross rollers is equivalent to two columns roller stack situation, therefore it should deduce roller calculation formula for two sets of roller respectively. According to the stress of the slewing bearings, we proceed load distribution calculation synthetically under the center of bearing axial force, overturning moment and radial force. Finally, based on the above formula for calculating the bearing load distribution and through the Matlab software, we analyze the influence of some parameters on the bearing load distribution. For ensuring bearing design parameter, it has the certain reference value.

Load Distribution Calculation of Pile Group Using Artificial Bee Colony Algorithm

Artificial bee colony algorithm (ABC) is a newly swarm intelligence optimization algorithm. It has become a powerful tool for solving highly nonlinear multi-peak optimization problems. The results of performances testing using three benchmark functions show that the numbers of evaluation for fitness function of ABC are obviously less than that using particle swarm optimization algorithm. Thus, ABC has better suitability for solving multi-modal optimization problems. Finally, ABC algorithm is applied to the load distribution calculation of pile group. The result shows that the ABC is feasible and has the advantages of high efficiency and easy implementation

Fatigue life prediction for cyclically bent threaded connections

In this paper it is shown that the modified norma-tive method improved by incorporating in the calculation the data of load distribution in threads is fitted for the fati-gue life prediction of cyclically bent threaded connections. The model for calculation of load and stress distribution along the thread based on elastic deformation properties of the full and partial profile turns pairs is used. Results of fatigue life prediction obtained for the cyclically bent threaded connections M16x2 are close to the experimental values, howerer do not exceed them. http://dx.doi.org/10.5755/j01.mech.17.2.324