Influence of the Contact Pressure on the Rolling Resistance Moments in Dry Ball-Race Contacts

2014 ◽  
Vol 658 ◽  
pp. 305-310
Author(s):  
Alina Corina Dumitrascu ◽  
Gelu Ianus ◽  
Dumitru Olaru
Keyword(s):  
Theoretical Model ◽  
Contact Pressure ◽  
Rotational Speed ◽  
Ball Bearing ◽  
Rolling Resistance ◽  
Theoretical Models ◽  
Hertzian Contact ◽  
Experimental Methodology ◽  
Experimental Values ◽  
Good Agreement

Based on a theoretical model and an experimental methodology for defining the rolling resistance moments in a modified thrust ball bearing having only 3 balls, the authors experimentally investigated the influence of the Hertzian contact pressure on rolling resistance moments between a ball and a race. The experiments were realized with balls having diameters between 1.588 mm and 4.762 mm with maximum Hertzian pressure between 0.2GPa and 1GPa, operating for rotational speed between 60rpm to 210 rpm. The experiments evidenced that the measured values of the rolling resistance moments have higher values that the theoretical hysteresis and curvature rolling resistance moments for low contact pressure. By increasing of the contact pressure to 1GPa the experimental values for rolling resistance moments are in good agreement with the theoretical models.

scholarly journals A NEW TYPE OF BREAKWATER UTILIZING AIR COMPRESSIBILITY

1988 ◽  
Vol 1 (21) ◽  
pp. 172 ◽  
Author(s):  
Masaaki Ikeno ◽  
Naokatsu Shimoda ◽  
Koichiro Iwata
Keyword(s):  
Energy Dissipation ◽  
Wave Energy ◽  
Theoretical Models ◽  
Pressure Variation ◽  
Wave Energy Dissipation ◽  
Air Chamber ◽  
New Type ◽  
Experimental Values ◽  
Better Than ◽  
Good Agreement

This paper is to investigate both theoretically and experimentally the wave energy dissipation and air-pressure variation of a new type of breakwater having a pressurized air-chamber and two buoyancy tanks. The theoretical models are developed in this paper and they are shown to be in good agreement with experimental values. The new type of breakwater proposed in this paper is pointed out to attenuate the transmitted wave much better than the rectangular-shaped and concave-shaped breakwaters without the air-chamber.

scholarly journals Theoretical Evaluation of Ultrasonic Velocities of Binary Liquid Mixtures of 1-Bromopropane in Chlorobenzene at 303.15, 308.15, 313.15 and 318.15 K

2014 ◽  
Vol 30 ◽  
pp. 9-17
Author(s):  
Ch. Praveen Babu ◽  
G. Pavan Kumar ◽  
B. Nagarjun ◽  
K. Samatha
Keyword(s):  
Intermolecular Interactions ◽  
Theoretical Models ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Ultrasonic Velocities ◽  
Theoretical Evaluation ◽  
Binary Liquid ◽  
Different Temperatures ◽  
Experimental Values ◽  
Good Agreement

Theoretical velocities of binary liquid mixtures of 1-bromopropane with chlorobenzene at 2 MHz and four different temperatures 303.15, 308.15, 313.15 and 318.15 K, have been evaluated as a function of concentration and temperature. The experimental values are compared with theoretical models of liquid mixtures such as Nomoto, Van Dael-Vangeel, Impedance Relation, Rao’s Specific Velocity Method, Junjie’s relations and Free Length Theory. In the chosen system there is a good agreement between experimental and theoretical values calculated by Nomoto’s theory. The deviation in the variation of U2exp/U2imx from unity has also been evaluated for explaining the non ideality in the mixtures. The results are explained in terms of intermolecular interactions occurring in these binary liquid mixtures.

scholarly journals Experimental and Theoretical Evaluation of Ultrasonic Velocities of Binary Liquid Mixtures of Anisaldehyde and Toluene at Different Temperatures

2011 ◽  
Vol 8 (3) ◽  
pp. 977-981
Author(s):  
CH. Srinivasu ◽  
K. Narendra ◽  
CH. Kalpana
Keyword(s):  
Ultrasonic Velocity ◽  
Theoretical Models ◽  
Liquid Mixtures ◽  
Binary Liquid Mixtures ◽  
Ultrasonic Velocities ◽  
Theoretical Evaluation ◽  
Binary Liquid ◽  
Different Temperatures ◽  
Experimental Values ◽  
Good Agreement

Theoretical velocities of binary liquid mixtures of anisaldehyde with toluene at 303.15, 308.15, 313.15 and 318.15 K have been evaluated by using theoretical models of liquid mixtures such as Nomoto, Van Dael-Vangeel, Schaff’s collision factor theory and Junjie’s relations. Density and ultrasonic velocity of these mixtures have also been measured as a function of concentration and temperature and the experimental values are compared with the theoretical values. A good agreement has been found between experimental and Nomoto’s theoretical ultrasonic velocities. The results are explained in terms of intermolecular interactions occurring in these binary liquid mixtures.

Slip-rolling resistance of ta-C and a-C coatings up to 3,000 MPa of maximum Hertzian contact pressure

2012 ◽  
Vol 43 (12) ◽  
pp. 1019-1028 ◽  
Author(s):  
M. Woydt ◽  
C. Scholz ◽  
C.-A. Manier ◽  
A. Brückner ◽  
V. Weihnacht
Keyword(s):  
Contact Pressure ◽  
Rolling Resistance ◽  
Hertzian Contact

scholarly journals Assessment of Morphological, Physical, Thermal, and Thermal Conductivity Properties of Polypropylene/Lignosulfonate Blends

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 543
Author(s):  
Mariane Schneider ◽  
Noriê Finimundi ◽  
Maria Podzorova ◽  
Petr Pantyukhov ◽  
Matheus Poletto
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Flame Retardant ◽  
Thermal Conductivity Coefficient ◽  
Theoretical Models ◽  
Sodium Lignosulfonate ◽  
Reactive Component ◽  
Experimental Values ◽  
Potential Use ◽  
Good Agreement

Lignosulfonate is a cheap material available in large quantities obtained as a byproduct of paper and cellulose. In this work, blends of polypropylene (PP) and sodium lignosulfonate (LGNa) were developed to evaluate the potential use of lignosulfonate as a lightweight, thermal insulation and flame retardant material. The blends were obtained by mixing in a torque rheometer and molded after compression. The blend proprieties were evaluated by physical, morphological, thermal, thermal conductivity, and flammability tests. The measured values were compared with theoretical models. The results indicated that a heterogeneous blend with a higher number of separated domains is formed when the LGNa content increases from 10 to 40 wt%. In addition, the density and thermal conductivity coefficient of the blends studied are not affected by the addition of LGNa. However, when the LGNa content in the blend exceeds 20 wt% the thermal stability and flame retardant proprieties are considerably reduced. The theoretical models based on the rule of mixtures showed a good agreement with the experimental values obtained from blend density, thermal conductivity, and thermal stability. In general, lignosulfonate tested in this work shows potential to be used as a reactive component in polymer blends.

Alpha particle preformation factor of spherical nuclei for 67 ≤Z ≤91

2019 ◽  
Vol 34 (05) ◽  
pp. 1950039 ◽  
Author(s):  
S. S. Hosseini ◽  
H. Hassanabadi ◽  
Dashty T. Akrawy
Keyword(s):  
Alpha Particle ◽  
Scaling Law ◽  
Analytical Formula ◽  
Theoretical Models ◽  
Alpha Decay ◽  
Proximity Potential ◽  
Spherical Nuclei ◽  
Experimental Values ◽  
Semi Empirical ◽  
Good Agreement

In this paper, alpha decay half-lives of spherical nuclei in the range [Formula: see text] are studied by considering the Coulomb and proximity potential model (CPPM) and calculating the alpha particle preformation factor. Comparisons are made to existing data in the literature. The half-lives are compared to the experimental values and also with the existing theoretical models, the analytical formula of Royer (R) and also within the modified analytical formula of Royer (MR) and New Akrawy–Poenaru Formula (AKRE) by Akrawy and Poenaru and the semi-empirical model based on fission theory (SemFIS) of Poenaru et al., the Universal Decay Law (UDL) of Qi et al., the Scaling Law of Brown (SLB), the Scaling Law of Horoi et al. (SLH). Compared with the experimental alpha half-lives, it can be found that the half-lives obtained using our formalism is in good agreement with the experimental data.

scholarly journals A theoretical model for predicting the vibration response of outer race defective ball bearing

2018 ◽  
Vol 7 (2) ◽  
pp. 289
Author(s):  
Samir Shaikh ◽  
Sham Kulkarni
Keyword(s):  
Theoretical Model ◽  
Ball Bearing ◽  
Mathematical Formulation ◽  
Vibration Response ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Outer Race ◽  
Rolling Element ◽  
Rolling Elements ◽  
Extended Type

The theoretical model with 2 degree-of-freedom system is developed for predicting the vibration response and analyze frequency properties in an extended type defective ball bearing. In the mathematical formulation, the contact between the races and rolling element considered as non-linear springs. The contact forces produced during the collaboration of rolling elements are obtained by utilizing Hertzian contact deformation hypothesis. The second order nonlinear differential equation of motion is solved using a state space variable method with the help of MATLAB software and the vibration acceleration response of the defective ball bearing presented in the frequency spectrum. The effects of variation in speed and size of the defect on characteristic frequency of extended fault on the outer raceway of the ball bearing have been investigated. The theoretical results of the healthy (non defective) and defective bearing are compared with each other.

Rigidity Analysis and Optimization of Warren Beams in Torsion

1977 ◽  
Vol 99 (1) ◽  
pp. 269-273
Author(s):  
R. C. Bahi ◽  
S. Chandra ◽  
P. C. Pandey
Keyword(s):  
Theoretical Model ◽  
Experimental Investigations ◽  
Rigidity Analysis ◽  
Static Performance ◽  
Weight Criterion ◽  
Experimental Values ◽  
Theoretical Results ◽  
Good Agreement

This paper reports analytical and experimental investigations on the static performance of warren beams in torsion. The theoretical results have been found to be in good agreement with the experimental values. The proposed theoretical model has further been used to obtain optimized proportions for the warren beams in terms of stiffness/weight criterion.

scholarly journals Removal mechanism of machinable ceramics and theoretical model of cutting force in turning operation

2019 ◽  
Vol 10 (2) ◽  
pp. 429-436
Author(s):  
Tao Liu ◽  
Lianjie Ma ◽  
Ye Wang ◽  
Wei Bai ◽  
Hao Chang
Keyword(s):  
Theoretical Model ◽  
Cutting Force ◽  
Cutting Speed ◽  
Propagation Path ◽  
Removal Mechanism ◽  
System A ◽  
Predicted Values ◽  
Experimental Values ◽  
Turning Test ◽  
Good Agreement

Abstract. The removal mechanism of machinable ceramics in turning was studied, and a theoretical model of cutting force based on energy theory was proposed. Based on the turning test of machinable ceramics and kinematics analysis of the tool-workpiece system, a model of tool-workpiece contact zone considering the tool tip arc radius was established. The crack propagation path and three stages of the crack development were analyzed from the stress perspective. Then the energy of the crack system was studied, and the brittle fracture energy which is more suitable for brittle materials was put forward. Based on the principle of energy conservation, a correction theoretical model of cutting force was established, which was verified by turning experiments of machinable ceramics. The results indicated that the predicted values of the model were in good agreement with the experimental values. Both theoretical model and experimental results demonstrated that the cutting force decreased as cutting speed increased, and increased as cutting depth and feed rate increased. This model enabled an in-depth understanding of the interaction action between the cutting tool and work materials involved in the turning of machinable ceramics.

One-Dimensional Contact Pressure Distribution of Radial Tires in Motion

1995 ◽  
Vol 23 (2) ◽  
pp. 116-135 ◽  
Author(s):  
H. Shiobara ◽  
T. Akasaka ◽  
S. Kagami ◽  
S. Tsutsumi
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Experimental Studies ◽  
Rolling Resistance ◽  
Leading Edge ◽  
Forward Direction ◽  
Contact Pressure Distribution ◽  
Support Ring ◽  
One Dimensional ◽  
Lowered Pressure

Abstract The contact pressure distribution and the rolling resistance of a running radial tire under load are fundamental properties of the tire construction, important to the steering performance of automobiles, as is well known. Many theoretical and experimental studies have been previously published on these tire properties. However, the relationships between tire performances in service and tire structural properties have not been clarified sufficiently due to analytical and experimental difficulties. In this paper, establishing a spring support ring model made of a composite belt ring and a Voigt type viscoelastic spring system of the sidewall and the tread rubber, we analyze the one-dimensional contact pressure distribution of a running tire at speeds of up to 60 km/h. The predicted distribution of the contact pressure under appropriate values of damping coefficients of rubber is shown to be in good agreement with experimental results. It is confirmed by this study that increasing velocity causes the pressure to rise at the leading edge of the contact patch, accompanied by the lowered pressure at the trailing edge, and further a slight movement of the contact area in the forward direction.

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