INFLUENCE OF ADDITIONAL SURFACE FINISHING TO THE MATERIAL PROPERTIES AND THE FLANK LOAD CARRYING CAPACITY OF CASE-HARDENED GEARS WITH GRINDING BURN

2017 ◽  
Vol 2017 (0) ◽  
pp. 05-08
Author(s):  
Johannes KOENIG ◽  
Peter KOLLER ◽  
Thomas TOBIE ◽  
Karsten STAHL
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Surface Finishing ◽  
Load Carrying Capacity ◽  
Grinding Burn ◽  
Load Carrying

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Load Carrying Capacity ◽  
Inflation Pressure ◽  
3D Finite Element ◽  
Load Carrying ◽  
Pavement Damage ◽  
New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

Influence of hard rolling and the cooling lubricant on the material properties and the rolling strength of PM gears

2019 ◽  
Vol 71 (3) ◽  
pp. 406-410
Author(s):  
Fritz Klocke ◽  
Thomas Bergs ◽  
Christoph Löpenhaus ◽  
Philipp Scholzen ◽  
Tim Frech
Keyword(s):  
Boundary Layer ◽  
Carrying Capacity ◽  
Material Properties ◽  
Rolling Process ◽  
Surface Zone ◽  
Load Carrying Capacity ◽  
Content Type ◽  
Load Carrying ◽  
Phosphorous Content ◽  
Cooling Lubricant

Purpose The lower density of powder metallurgical (PM) gears compared to solid steel gears leads to not only a lower weight but also a lower load-carrying capacity. Therefore, PM gears are cold rolled before hardening to increase the density in the highly stressed surface zone and, thus, the flank load-carrying capacity. A further approach to increase the flank load-carrying capacity is the reduction of friction and wear in the tooth contact. The purpose of this paper is to analyze the hard rolling process as a new manufacturing step in the PM process chain to influence the boundary layer. Design/methodology/approach The investigation includes the new process of hard rolling, the variation of the cooling lubricant in the hard rolling process and the evaluation of its influence on the material properties and the flank load-carrying capacity. Therefore, the additives of the cooling lubricant are varied regarding the sulfur and phosphorous content. The load-carrying capacity is evaluated on disk-on-disk test rig and the material properties are evaluated by metallographic tests and boundary layer. Findings The results of the specimen characteristics in the micro and nano range show a significant influence of hard rolling on the residual stresses and the chemical surface composition. Because of hard rolling, residual compressive stresses as well as roughness are reduced and the flank load-carrying capacity is increased by high phosphorous content of the cooling lubricant. Originality/value This paper investigates a new manufacturing step to increase resource efficiency by increasing the flank load-carrying capacity of spur gears.

Surface Damage Caused by Gear Profile Grinding and Their Effects on Flank Load Carrying Capacity

2003 ◽  
Author(s):  
Fritz Klocke ◽  
Heiko Schlattmeier
Keyword(s):  
Surface Properties ◽  
Carrying Capacity ◽  
Material Removal ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Surface Zone ◽  
Load Carrying Capacity ◽  
Grinding Burn ◽  
Load Carrying ◽  
Tooth Flank

Instances of damage to discontinuous form ground and surface-hardened gears, especially of large scale, have recently increased. This damage may be attributed partly to a faulty grinding process with negative effects on the surface zones and the surface properties. In addition to its high accuracy, discontinuous form grinding is characterized by high material removal because of the line contact between grinding wheel and tooth flank. The efficiency and reliability of the process are affected not only by the use of optimized grinding wheel specifications and machining parameters, but also by the risk of local surface zone damage in the form of grinding burn on the tooth flank. The location and onset of local grinding burn damage have seemed for a long time to be random and unpredictable, for which reason the feed rates and material removal rates have been increased only incrementally in procedures used in industrial practice. The studies reported in the paper are intended to contribute to the knowledge of the interrelationships between surface zone damage and the effects on flank load-carrying capacity for the case of profile grinding. Grinding tests have been conducted in order to investigate more closely the occurrence of surface properties in the form of grinding burn as a function of grinding parameters. Further studies of the flank load carrying capacity of case hardened gears subjected to different surface properties are intended to provide a more detailed analysis of the interrelationship between gear geometry and different surface properties during the grinding process in a first step.

Grinding Burn on Gears: Correlation Between Flank-Load-Carrying Capacity and Material Characteristics

2013 ◽  
pp. 113-123
Author(s):  
Bernd-Robert Höhn ◽  
Karsten Stahl ◽  
Peter Oster ◽  
Thomas Tobie ◽  
Simon Schwienbacher ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Grinding Burn ◽  
Material Characteristics ◽  
Load Carrying

Variational Method for Limit Load Analysis of Inhomogeneous Media

2009 ◽  
Author(s):  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Limit Load ◽  
Load Carrying Capacity ◽  
Element Analysis ◽  
Strain Fields ◽  
Adjustment Procedure ◽  
Load Carrying ◽  
Load Analysis

The load carrying capacity of a body with varying material properties (inhomogeneous) is investigated using the various lower and upper bound limit load multipliers in the context of varational principles originally proposed by Mura and co-workers. In order to evaluate the different limit load multipliers, Elastic Modulus Adjustment Procedure (EMAP) is used to obtain statically admissible stress and kinemattically admissible strain fields at a limit load stage. The proposed upper and lower bound limit load solutions are compared with the results obtained from inelastic finite element analysis (FEA) for several examples with two-dimensional and three-dimensional geometries.

Flank-Load-Carrying Capacity of Case Hardened Gears With Grinding Burn

2011 ◽  
Author(s):  
Bernd-Robert Ho¨hn ◽  
Karsten Stahl ◽  
Peter Oster ◽  
Thomas Tobie ◽  
Simon Schwienbacher ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Carrying Capacity ◽  
Experimental Testing ◽  
Load Capacity ◽  
Experimental Tests ◽  
Load Carrying Capacity ◽  
Grinding Burn ◽  
Residual Stress State ◽  
Load Carrying

A high geometric accuracy of case-hardened gears requires a grinding process after heat treatment. Inappropriate grinding conditions can induce surface tempering, alter hardness and lead to an unfavorable residual stress state. This effect is commonly known as grinding burn. The influence of grinding burn on the flank-load-carrying capacity was systematically investigated within a research project. The results of experimental tests and the analysis of surface and near subsurface parameters allowed a correlation between grinding burn grade, material characteristics and flank-load-carrying capacity. A main result of this project is a proposal for the calculation of surface durability of gears which implicates the influence of grinding burn. This paper summarizes results of the experimental testing and the accompanying analyses. The main focus herein is the consideration of an altered hardness and residual stress state in a material-physically based model for calculating the load capacity of gears.

Influence of Yield Strength Variability over Cross-Section to Steel Beam Load-Carrying Capacity

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala
Keyword(s):  
Yield Strength ◽  
Cross Section ◽  
Carrying Capacity ◽  
Bending Moment ◽  
Statistical Characteristics ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Strength Variability ◽  
Hot Rolled ◽  
Hot Rolled Steel

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.

Fuzzy Sets Theory in Comparison with Stochastic Methods to Analyse Nonlinear Behaviour of a Steel Member under Compression

2005 ◽  
Vol 10 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Z. Kala
Keyword(s):  
Fuzzy Sets ◽  
Carrying Capacity ◽  
Stochastic Methods ◽  
Nonlinear Behaviour ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Input Parameters ◽  
Stochastic Solution ◽  
Fuzzy Solution ◽  
Sets Theory

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.

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