Settlement Analysis of machine foundation Under Reciprocating Load using FEM

Abstract

The analysis of the machines foundations is an important issue in the geotechnical engineering as the foundations of the machine provide a strong platform for the machines to work in a smooth manner with minimal maintenance requirements. The process of analyzing of the machines foundations requires more attention since it includes not only the static loads but also the dynamic loads that result from the unbalanced forces that the machine generates or its vibratory motion. Of course, this movement load is transferred to the soil through the foundation and its effect can be calculated using the principles of kinetic soil and vibration theory. Here, the search deals with the study of analyzing machines foundations under the influence of kinetic loads taking into consideration the type of soil and its condition, the shape of the foundation and its location from the surface of the earth, the type of kinetic load projected and the method of analysis. In this study, and for the purpose of achieving what has been mentioned with using finite element method (program Plaxis 2D V8.6 ) three types of sandy soil (Loose, medium and dense) were taken. The effect of dynamic loads on different types of machine foundations (square, rectangular, and strip) was studied and under the influence of a different dynamic frequency (5,10,15, 20 Hz) was studied and the effect of a group of these factors on the amount of displacement of the machine foundation was studied and these results were compared with the maximum Amplitude when resonating with a special parameter called Normalized Displacement. It is noted from this study that the value of the displacement decreases by increasing the values of the (L / B) ratio of the foundation for the same frequency for the three soil states, , and that the increase the value of the elastic modulus (E), the Normalized displacement value approaches the number (1), that meaning it approaches the resonance at the frequency ( 5 Hz) for the case of the square foundation more than the rectangle and the strip , and for the remaind of the frequencies (10, 15, 20 Hz) the Normalized displacement value will be less compared to the frequency (5 Hz) as well as less variation between the cases of different foundations shape.