A Study of Influence of the Machining Accuracy on Reliability of Cycloidal Gears

2020 ◽  
pp. 9-17
Author(s):  
Y.V. Sinitsyna
Keyword(s):  
Probability Of Failure ◽  
High Load ◽  
Maximum Effect ◽  
Machining Accuracy ◽  
Positional Error ◽  
Aircraft Industry ◽  
Load Bearing Capacity ◽  
The Monte Carlo Method ◽  
Manufacturing Errors ◽  
Fixed Period

Cycloidal gears are widely used in modern robotics, aircraft industry and other industries due to their compactness, high load bearing capacity, rigidity and accuracy. This paper examines a method for calculating stresses at the points of contact of the satellite gear and the pins taking into account manufacturing errors. Based on the Monte Carlo method, the probability of failure-free operation of the cycloid gear is determined by the criterion of contact endurance, taking into account the randomness of deviations of gear sizes from the nominal ones. Graphs showing the relationships between the probability of failure-free operation for a fixed period of time and the torque are presented. It is established that a 2kv gear has a higher reliability compared to the gear manufactured using the khv scheme. Based on the analysis of sensitivity of the failure-free operation probability to manufacturing errors, it is concluded that the positional error of the pin hole has the maximum effect on the gear performance.

scholarly journals Constructing a biomimetic robust bi-layered hydrophilic lubrication coating on surface of silicone elastomer

Friction ◽  
2021 ◽  
Author(s):  
Luyao Gao ◽  
Xiaoduo Zhao ◽  
Shuanhong Ma ◽  
Zhengfeng Ma ◽  
Meirong Cai ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Composite Layer ◽  
High Load ◽  
Silicone Elastomer ◽  
Aqueous Lubrication ◽  
Low Friction ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Lubrication Performance ◽  
Wide Range

AbstractSilicone elastomers-based materials have been extensively involved in the field of biomedical devices, while their use is extremely restricted due to the poor surface lubricity and inherent hydrophobicity. This paper describes a novel strategy for generating a robust layered soft matter lubrication coating on the surface of the polydimethylsiloxane (PDMS) silicone elastomer, by entangling thick polyzwitterionic polyelectrolyte brush of poly (sulfobetaine methacrylate) (PSBMA) into the sub-surface of the initiator-embedded stiff hydrogel coating layer of P(AAm-co-AA-co-HEMA-Br)/Fe, to achieve a unified low friction and high load-bearing properties. Meanwhile, the stiff hydrogel layer with controllable thickness is covalently anchored on the surface of PDMS by adding iron powder to provide catalytic sites through surface catalytically initiated radical polymerization (SCIRP) method and provides high load-bearing capacity, while the topmost brush/hydrogel composite layer is highly effective for aqueous lubrication. Their synergy effects are capable of attaining low friction coefficient (COFs) under wide range of loaded condition in water environment with steel ball as sliding pair. Furthermore, the influence of mechanical modulus of the stiff hydrogel layer on the lubrication performance of layered coating is investigated, for which the COF is the lowest only when the modulus of the stiff hydrogel layer well matches the PDMS substrate. Surprisingly, the COF of the modified PDMS could remain low friction (COF < 0.05) stably after encountering 50,000 sliding cycles under 10 N load. Finally, the surface wear characterizations prove the robustness of the layered lubricating coating. This work provides a new route for engineering lubricious silicon elastomer with low friction, high load-bearing capacity, and considerable durability.

Dynamic Analysis and Experimental Research of Laser Cutting Machines

2014 ◽  
Vol 915-916 ◽  
pp. 31-34
Author(s):  
Qing Ping Zhang ◽  
Zheng Ru Wang ◽  
Yan Fang Wang
Keyword(s):  
Machine Tool ◽  
Modal Analysis ◽  
Laser Cutting ◽  
Machining Accuracy ◽  
Dynamics Analysis ◽  
Theoretical Base ◽  
Test Results ◽  
Cutting Machine ◽  
Manufacturing Errors ◽  
Theoretical Results

Vibration is one of the most important problems in laser cutting machine tool, which causes the manufacturing errors, also influences the machining accuracy of the parts. Modal analysis can calculate vibration type of structures. The paper presents how to use the powerful FEA software ANSYS to do the modal analysis on laser cutting machine tool and also studies the undamped free vibration on laser cutting machine tool. Finally, the test results and theoretical results were compared to verify the rationality of the modal, these provide theoretical base and conditions for dynamics analysis and optimal design.

Continuously Growing Ultrathick CrN Coating to Achieve High Load-Bearing Capacity and Good Tribological Property

2018 ◽  
Vol 10 (3) ◽  
pp. 2965-2975 ◽  
Author(s):  
Zechao Li ◽  
Yongxin Wang ◽  
Xiaoying Cheng ◽  
Zhixiang Zeng ◽  
Jinlong Li ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Tribological Property ◽  
High Load ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Crn Coating

scholarly journals Numerical Simulation Study Of Squeezed Branch Piles Based On Post-grouting Technology

2021 ◽  
Vol 292 ◽  
pp. 01038
Author(s):  
LiXing Ma ◽  
ZhuoPeng Shi ◽  
Kai Han ◽  
PengFei Chang ◽  
XiaoDong He
Keyword(s):  
Bearing Capacity ◽  
Load Transfer ◽  
High Load ◽  
Single Pile ◽  
Horizontal Force ◽  
Load Bearing Capacity ◽  
Load Transfer Mechanism ◽  
Post Grouting ◽  
Vertical Bearing ◽  
Excellent Stability

The squeezed branch pile has strong resistance to pressure, pullout and horizontal force, and it also has excellent stability, which makes it widely used in the field of electrical engineering. Based on the ABAQUS, the paper simulates the vertical bearing situation of post-grouting squeezed branch piles, by setting up Set two comparisons of single pile and squeezed branch pile, the bearing capacity, load transfer mechanism and failure mode of post-grouting squeezed branch piles were comprehensively analyzed and compared. Studies have shown that the bearing capacity of the squeezed branch piles with post-grouting technology has increased by 68.1% compared with the traditional squeezed branch piles, and the bearing characteristics of the branches have changed greatly. In this process, the end-bearing function of the branch plate is fully exerted, and the high load-bearing capacity of the grouted strata soil is used to reduce the settlement.

scholarly journals Load-carrying capacity of welded K-type joints inside floor truss systems

2019 ◽  
Vol 52 (1) ◽  
pp. 38-52
Author(s):  
Pooya Saremi ◽  
Wei Lu ◽  
Jari Puttonen ◽  
Dan Pada ◽  
Jyrki Kesti
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Carrying Capacity ◽  
Numerical Models ◽  
High Load ◽  
Load Carrying Capacity ◽  
Finite Element Analyses ◽  
Load Bearing Capacity ◽  
Load Carrying ◽  
Joint Behaviour

The load-carrying capacity of a K-type joint inside a floor truss is studied both experimentally and numerically. The joint tested is a scaled-down, isolated joint. The tubular braces, plate chord, and division plate are made of SSAB Domex steel. Comparison of load displacement curves received by finite element analyses with curves obtained from tests confirms that numerical models describe joint behaviour reasonable. The paper demonstrates that joints with high load-bearing capacity can be investigated experimentally by scaling the dimensions of the joint down when testing devices can affect the required capacity of the joint. The results presented can also be used for optimizing failure mechanism of similar joints in practice.

Design of Concrete Hinges According to Leonhard

2020 ◽  
Vol 309 ◽  
pp. 163-168
Author(s):  
Peter Havlíček ◽  
Július Šoltész
Keyword(s):  
State Of The Art ◽  
High Load ◽  
Steel Plates ◽  
Construction Process ◽  
Load Bearing Capacity ◽  
State Of Stress ◽  
High Durability ◽  
The Usa ◽  
Alternative Type ◽  
Empirical Approaches

Concrete hinges are characterized by a high load-bearing capacity and deformability. They are nearly maintenance-free and have a high durability if designed and constructed properly. Concrete hinges are perfectly suited to control the flow of forces and to efficiently reduce constraints. The concept more than 130 years old. The first massive joints were developed by Claus Kӧpcke already in 1880. However, due to the difficult construction process, an alternative type of joint was developed, where the concrete contact surface was replaced with embedded lead or steel plates. The breakthrough in this technology was made by Augustine Masnager, who in 1908 developed a durable and easy-to-manufacture reinforced concrete hinge. While Masnager attributed the transfer of the entire load to the reinforcement, French engineer Eugène Freyssinet proved that the throat reinforcement is unnecessary because the load is transmitted through a thin layer of concrete in the throat due to the tri-axial state of stress. This technology is now used throughout Europe and the USA. The best-known experts in this field were Fritz Leonhardt, E.O. Fessler and G.D. Base. Today's design models are based on their research. The vast majority of them are based on empirical approaches and disallow the proper construction of concrete hinges up to the state-of-the-art. For this reason, the research shows effort to modernize them.

An Investigation Into Fixture Error Compensation in Micromilling Using Tool-Based Conductive Touch-Off

2010 ◽  
Author(s):  
Jacob A. Kunz ◽  
Angela Sodemann ◽  
J. Rhett Mayor
Keyword(s):  
Tool Path ◽  
Micro Milling ◽  
Machining Accuracy ◽  
Positional Error ◽  
Curved Surfaces ◽  
Milling Tool ◽  
Micro Features ◽  
Tool Stresses ◽  
Compensation Approach ◽  
Forward Kinematic

In micro-milling, decreased tool size leads to a need for tighter tolerances for fixture error in order to avoid excessive tool load and maintain machining accuracy. In 4-axis machining on a curved surface, fixture errors propagate cumulatively leading to a significant error at the tool tip. As a result a compensation approach is essential to successful microfeature production on curved surfaces. Tool stresses are shown to be highly dependent on the amount of fixture error. The scaling down of tool sizes is shown to result in an exponential increase in tool stresses. This paper proposes the use of a conductive touch-off method that utilizes the milling tool in its spindle to perform an in-situ registration mapping of positional errors. The fixturing errors are characterized using the Denavit-Hartenberg robotic linkage convention. A forward kinematic solution uses homogeneous transformation matrices to investigate the effects of fixturing errors on milling tool path errors in 4-axis micro-milling on curved surfaces. The touch-off registration measures the positional error in the tool axis direction allowing for axial tool position compensation. This results in decreased tool stresses and increased channel depth accuracy which is necessary for successful milling. A preliminary implementation of the conductive touch-off registration approach has demonstrated the efficacy of the technique when applied to production of micro-features on concave surfaces.

THE CALCULATION OF BACKLASH IN THE GEARS BY USING THE MONTE CARLO METHOD

2020 ◽  
pp. 42-47
Author(s):  
B. P. Timofeev ◽  
N. T. Dang ◽  
M. H. Tran
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Probabilistic Method ◽  
Spur Gears ◽  
The Monte Carlo Method ◽  
Manufacturing Errors ◽  
Distribution Laws ◽  
Lateral Clearance ◽  
Gear Wheels ◽  
Maximum Method

This paper is devoted to ensuring normal lateral clearance during the normalization of manufacturing errors of gear wheels and non-gear transmission elements. The task is complicated by the fact that GOST 1643–81 sets tolerances and maximum deviations relative to the working axles of the gears. The methods of calculating the lateral clearance of spur gears are considered. As the influencing factors on the lateral clearance, the thermal expansion of the link materials, the deviation of the interaxial distance of the wheels, the deviation of the engagement pitch, the radial run-out of the gear crowns, the error in the direction of the tooth, the parallelism and skew of the axles of the wheels are taken into account. The transmission accuracy parameters are read randomly. The results of calculation by the minimum-maximum method and the probabilistic method are compared. As a probabilistic calculation method, the Monte Carlo method is adopted. The input calculation parameters are taken equal to the maximum allowable values from GOST 1643–81, the parameters of the kinematic error of the wheels for calculation by the probabilistic method are considered distributed according to the equally probable and normal distribution laws.

A probability model for fibrous composites with local load sharing

1980 ◽  
Vol 372 (1751) ◽  
pp. 539-553 ◽  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Extreme Value Theory ◽  
Probabilistic Analysis ◽  
Asymptotic Theory ◽  
Probability Model ◽  
Probability Of Failure ◽  
Value Theory ◽  
Fibrous Composites ◽  
The Monte Carlo Method

The chain-of-bundles model for fibrous composites is reviewed, and an approximation to the probability of failure is derived. This leads to formulae for predicting the strength of such a composite. These formulae are developed in the context of an asymptotic theory, and the Monte Carlo method is used to study a specific case in more detail. We also discuss the size effect. The probabilistic analysis relies heavily on extreme value theory, and a brief survey of the relevant parts of that theory is included.

Exit Condition for Probabilistic Assessment Using Monte Carlo Method

2010 ◽  
Vol 10 (1) ◽  
pp. 1-9
Author(s):  
Jakub Valihrach ◽  
Petr Konečný
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Optimization Design ◽  
Random Variable ◽  
Probability Of Failure ◽  
Probabilistic Assessment ◽  
Theoretical Derivation ◽  
The Monte Carlo Method ◽  
The Relationship

Exit Condition for Probabilistic Assessment Using Monte Carlo Method This paper introduces a condition used to exit a probabilistic assessment using the Monte Carlo simulation, and to evaluate it with regard to the relationship between the computed estimate of the probability of failure and the target design probability. The estimation of probability of failure is treated as a random variable, considering its variance that is dependent on the number of performed Monte Carlo simulation steps. After theoretical derivation of the decision condition, it is tested numerically with regard to its accuracy and computational efficiency. The condition is suitable for optimization design using the Monte Carlo method.

Sign in / Sign up

Export Citation Format

Share Document