Numerical study of the use of Non-destructive Impact Test methods for the exam of integrity of concrete piles

This research includes a numerical study using Finite Element Method aims to evaluate the ability and accuracy of using Non-destructive Impact Response Method in the assessment of length and cross-sections of intact concrete pile (not deformed) in both time and frequency domains. Therefore, an appropriate numerical model depends on the modeling of both impact force (impulsive load) and distributing medium (pile + soil) and insert them in computing software ABAQUS was carried out. The numerical model was verified corresponding to field measures obtained from literature review and the results showed good agreement between measures and numerical results. Furthermore, the model was applied on a typical example in order to study vibration distribution in the pile due to impulsive load applied on pile top. Mechanical response curve of intact pile was obtained. Then, both of length and cross-section area of the pile were determined. Finally, parametrical study of most important factors (stiffness of soil surrounding the pile and length of pile embedded in the soil) effect on vibration distribution resulted from impulsive load applied on pile top. The parametrical study was carried out in two domains; first one was time domain depending on the direct analysis of particle displacement and velocity and the second was frequency domain depending on analysis of pile mechanical response curve. The results of this research enables to use the proposed numerical model to numerically obtain the time history of particle displacement and velocity in addition to the curve of mechanical response computed in the pile top and forms reference diagrams which is used later to compare with similar diagrams resulted from field test of executed piles. As a result, pile integrity test and detecting of defects in the piles if any. In addition, the limits of the use of both analysis methods adapted in research and choose the best between them according to the case study.

A half-numeric method for Calculation the volume resulting from the intersection of a cylinder with a ball as a function of the impact parameter by using the Mathematical program mathCAD

We have developed an analytic expression for the volume of intersection of any cylinder with any sphere in the usual threedimensional space, and give examples of its usefulness for physics. Produced from surface collisions either elastic collision, or inelastic collision, for the incoming energies greater than the binding energy of the nucleons in the nucleus, the reaction occurs and thus the effective size (what the target nucleus see from the nuclear material in the projectle, and What the projectle see from the nuclear material in the target nucleus) is formed and so for the different collisions parameters .

Studying the mechanical properties of composite material based on unsaturated polyester reinforced with random fiberglass

This research includes an experimental study for the manufacture of a composite material based on polymer (unsaturated polyester), reinforced with random fiberglass at different weight fractions. By suite, it has been studied some mechanical properties of the models manufactured, to determine the effect of glass fiber content on the tensile strength, hardness and impact resistance. This study has shown that the best results were for samples reinforced by 40% fiberglass, where the tensile strength increased about 70%, hardness up to 30%, and impact resistance about 43%. It will be observed that the mechanical properties decrease clearly at 60% of weight fraction of fiberglass. This fact can be related to the quantity of unsaturated polyester become inadequate for recharge of the fibers, which leads to weakness in the forces bonding in composite materials.

The effect of seismic pounding on the buildings in different geometric and dynamic properties

The phenomenon of impact between the adjacent buildings is one of the most important reasons for collapse of buildings during the earthquakes for that most of the codes resort to avoid impact by increasing the distance between adjacent buildings, but on the other hand high cost of land requires us to take advantage of the largest possible area in addition to the difficulty of making the separation architecturally and in particularly for high buildings the separation may offer up to 50 cm. We tried to have this research one of the studies that discuss the subject of seismic pounding where we discussed the methods for modeling the pounding and the most appropriate way to study the impact depending on the program dynamic analysis Ansys (Autodyn Ver. 11) then chose several cases for study seismic impact in three-dimensional models to cover most of the study variables that may affect this phenomenon, and we doer non- linear dynamic analysis for all cases, with applying acceleration function is defined by equation its constants are changing with processing the seismic records data. After finishing the analysis for all the models we have discussed changing the transitions and stresses and strains , and studied the factors affecting the impact , and discussed results of study and then we have summarizes the recommendations in that we see fit through this search.

Optical and Structural Properties of Thermally Evaporated CdTe Thin Films

CdTe Thin films were deposited on silicon substrates by thermal evaporation method. The geometric thickness was calculated using interferometric method based on reflectance curve recorded with the spectrophotometer. The Reflection of High-Energy Electron Diffraction (RHEED) patterns and XRD analysis reveals that the structure of the films are polycrystalline with preferential orientation (111). The structure constant (a), crystallite size (D), dislocation density (δ) and strain (ε) were calculated, and it is observed that the crystallite size increases but micro-strain and dislocation density decreases with increases in thin film thickness. The composition of the samples was determined by Energy Dispersive X-ray Analysis (EDX) and it is found that the wt.% of Cd increases and the wt.% of Te decreases with the increases of film thickness due to the re-evaporation of Te.