Physical testing of rubber. Determination of tear strength

1997 ◽  
Keyword(s):  
Tear Strength ◽  
Physical Testing

A Project in the Determination of the Moment of Inertia

2005 ◽  
Vol 33 (4) ◽  
pp. 319-338
Author(s):  
Ron P. Podhorodeski ◽  
Paul Sobejko
Keyword(s):  
Dynamic Properties ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Moment Of Inertia ◽  
Educational Goal ◽  
Centre Of Mass ◽  
Comparison Of Results ◽  
Physical Testing ◽  
The Moment

Analysis of the forces involved in mechanical systems requires an understanding of the dynamic properties of the system's components. In this work, a project on the determination of both the location of the centre of mass and inertial properties is described. The project involves physical testing, the proposal of approximate models, and the comparison of results. The educational goal of the project is to give students and appreciation of second mass moments and the validity of assumptions that are often applied in component modelling. This work reviews relevant equations of motion and discusses techniques to determine or estimate the centre of mass and second moment of inertia. An example project problem and solutions are presented. The value of such project problems within a first course on the theory of mechanisms is discussed.

Vulcameter Determination of Best Cure

1965 ◽  
Vol 38 (4) ◽  
pp. 757-768 ◽  
Author(s):  
S. D. Gehman ◽  
F. S. Maxey ◽  
S. R. Ogilby
Keyword(s):  
Rate Constant ◽  
Work Load ◽  
Service Performance ◽  
Stress Strain ◽  
First Order ◽  
Testing Laboratories ◽  
Physical Testing ◽  
Strain Testing ◽  
Minimum Number

Abstract Using a continuous cure curve to select a minimum number of stepped cures, it should be possible to vulcanize and test fewer sheets to determine best cure. This procedure is attractive for its potential of expediting the output of physical testing laboratories and especially for reducing the work load of stress-strain testing. Cure curves recorded with the Vulcameter approximated first-order reactions. Equations were derived to calculate the final force and rate constant from recorded force values without carrying the reaction to completion. A chart is suggested to assist in calculating the rate constant. Time for a given fractional rise in force depends only on the rate constant so that a chart for obtaining it is relatively simple. Experience and correlation with service performance in selecting best cures is emphasized. 95% rise times from Vulcameter curves were compared with conventionally selected best cures for a wide variety of compounds. Indications are that experience with the method might reduce the number of test-sheet cures to determine optimum stress-strain properties to one, two, or three depending upon the compound and the exactness required.

Theoretical and Experimental Determination of Proppant Crushing Rate and Fracture Conductivity

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Dali Guo ◽  
Yunxiang Zhao ◽  
Zixi Guo ◽  
Xianhui Cui ◽  
Bo Huang
Keyword(s):  
Oil And Gas ◽  
Search Algorithm ◽  
Mechanical Analysis ◽  
Experimental Conditions ◽  
Fracture Conductivity ◽  
The Monte Carlo Method ◽  
Physical Testing ◽  
Value Decomposition ◽  
Svd Method

Abstract Proppant is an important material for hydraulic fracturing that impacts the production and production cost of oil and gas wells. The key properties of proppant are crushing rate and fracture conductivity. The most common way to evaluate the key properties of proppant is physical testing, but this method is time-consuming and costly, and it may result in different results under the same experimental conditions. This paper presents a method for calculating proppant crushing rate and fracture conductivity, which are obtained by combining a series of simple and economical laboratory experiments with a significant amount of numerical calculations under various experimental conditions. First, the arrangement of proppant particles was simulated, and the location of particles was determined with the Monte Carlo method, the optimization model, and search algorithm in this process. Second, by mechanical analysis of proppant particles, a mathematical model of force was established, and the singular-value decomposition (SVD) method was used to calculate the force of each particle. Third, the crushing rate of proppant particles was calculated under irregular conditions using mathematical statistics. The Kozeny–Carman equation was improved on to establish a fracture conductivity model. Finally, the average fracture conductivity was calculated on the basis of the simulation results. The calculated fracture conductivity is consistent with the experimental results, which verifies the accuracy of the model.

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