Contribution to the Determination of the Elasticity Modules of a Material (Borassus Aethiopum) based on an Experimental Method: Effort (Force)/Elongation or Moment/Degree ratio
Abstract
The mechanical characterization of a material involves the determination of longitudinal elastic modulus, the transverse modulus and the fish coefficient. To Obtaining these data is subject to experimentation. To obtain these data, there is need to experimentation. Several conditions contribute to the realization to the carrying out of the tests.To achieve this, there are methods which make it possible to better know the materials in general and especially the building materials by working on very small samples. Machinery, sample deposits and working conditions are obstacles to research. A civil engineering CBR press enabled us, during the three-point bending test, to determine the modulus of longitudinal elasticity by increasing the press force and elongation. Based on the example of bending, the transverse module is obtained by the torsion test based on the torsion moment and the torsion angle
The method is based on consideration of the Bending Effort/Elongation ratio or Moment/Torsion angle ratio. The experimental material is an object with its own morphology, the wandering wood. The difficulty of the work is related to the accuracy of all components of the sample.This method complements previous methods and puts into practice the indispensable dimensions of the strength of the materials.It shows the purpose pursued by an engineer in these experiments.
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Introduction
One of the ways to know a material and its solicitation behavior is the characterization. It can be done in several fields: physics, mechanics, acoustics,... and in several ways. But for each domain, the characterization follows rules and principles: it is based on laws. It depends on the information sought. The main characterization techniques are mechanical tests, nondestructive tests and physico-chemical analyzes. In the case of mechanical and rheological characterization, machines or apparatus such as a mechanical phenomena analyzer, a rheometer, a bending machine are indicated for destructive or nondestructive tests based on the vibratory method in which the specimen is not destroyed.
Depending on the method of testing (destructive or not), methods such as the vibratory method, the ultrasonic method adopted on "Stress grading" are also used. Vibratory tests led to the determination of the longitudinal elastic modulus (MOE). Authors (Jehl et al, 2011, Viguier et al, 2015, JG van de Kuilen, 2002) have revealed the importance of the vibratory method. A similar method is the ultra sonic method of analyzing the speed of sound propagation in the sample. Another method based on the diffusion of X-rays. The aim is to measure the flux of ray that passes through the material over a period of time.These methods are performed on specified equipments or machines having sensors or detectors reading dimensional extensions. The principle must meet standards. In these standards, the experimental conditions, the number, the shape and the dimensions of the sample are to be respected.The characterization work must be carried out on the most suitable apparatus and machines [1]. The technique of the shapes of the materials must dictatethe shape of the samples. Experience data are to be considered. Unfortunately, these parameters differ according to the materials and objects to be manufactured. The damage during these characterization works is related to the testing machines and the popularity of samples. That is why we say the problem of the popularity of the samples remains.
Experimental material is limited. The probability of finding the same sample with the same characteristics is low. This is similar to archeology studies. It is very rare to be able to carry out physic-mechanical characterizations on old materials found in excavations or on works in restoration.
Conclusion
Better knowledge of a material and its behavior in the face of the various demands require the deployment of an appropriate test machine and the important deposit to assess the quality of the result statistically. The absence of an adequate machine is solved by the development of a simple technique based on the ratio Stress / Elongation or Moment / Angle of torsion ratio. This experience constitutes the solution to the lack of machine. This technique will allow the learner to get to work. The combination of these two tests provides information about longitudinal and transverse modules with unexpected accuracy.