Prediction of Dynamic Elastic Properties for Mishrif formation in West Qurna-1 oil field: an experimental work

Shear and compressional wave velocities are useful for drilling operations, the exploration of reservoirs, stimulation processes, and hydraulic fracturing. An ultrasonic device will be used in this investigation to anticipate and analyze the elastic characteristics of carbonate rocks. At the summit of the field, the well WQ1-20 obtained samples of the Mishrif formation from a variety of various depths. The number of samples taken from the well is nine from different units whereas the number of samples taken from the main unit (MB2) was five. The relations between the elastic properties for the carbonate rocks with P-and S-waves were defined. The relations between Vp and Vs with elastic properties were defined by applied Regression analysis. The results showed that a linear relationship between P-and S-wave velocities with the elastic properties of the carbonate rocks. It is found that the relationship between Vp and Young's modulus (E) is R2 equal to 0.979 while the relationship between Vs and Young's modulus (E) is R2 equal to 0.925. The relationship between shear modulus and Vs is good in comparison with Vp where the values of R2 were 0.985 and 0.94 respectively. R2 values for the Bulk modulus and Lame's constant of Vp are 0.925 and 0.6, respectively, while the values for Vs are 0.925 and 0.6 for the latter. The relation between Vp/Vs ratio with Poisson’s ratio showed a good R2 with a value of 0.97. When it comes to predicting the dynamic elastic characteristics of a material, the ultrasonic approach may be regarded as a cost-effective, easy, and non-destructive method.

Study of the strengthened state near the forces for the semi-plan

Many of the engineering applications have faced the delicate contact problem in the area close to the forces where it is very difficult to experimentally carry out various measurements and draw important conclusions on the condition of the contact points. In this paper the forced state in the vicinity of the forces for the half-plane will be studied. Furthermore, the qualities displayed by the half-plane under the action of normal forces, tangential forces and the moment caused by a pair of forces will be analyzed, as well as changes in the elastic characteristics for the forced plane state and the deformed plane state.

The Influence of Base Layer Thickness in Flexible Pavements

Flexible pavement design and analysis were carried out in the past with semi-experimental methods, using elastic characteristics of pavement layers. Due to the complex interferences between various layers and their time consumption, the traditional pavement analysis, and design methods were replaced with fast and powerful methods including the Finite Element Method (FEM) and the Discrete Element Method (DEM). FEM requires less computational power and is more appropriate for continuous environments. In this study, flexible pavement consisting of 5 layers (surface, binder, base, subbase, and subgrade) had been analyzed using FEM. The ABAQUS (6.14-2) software had been utilized to investigate the influence of the base layer depth on vertical stresses and displacements. Three different thicknesses were adopted (10, 20, and 30cm) with constant other pavement layer thicknesses. The results of this study showed that the stress levels at the top of the base layer increased by about 37% when the thickness of this layer increased from 10cm to 30cm, while the stress levels at the top of the subbase layer decreased by about 64%. When the base layer increased from 10 to 20, from 20 to 30, and from 10 to 30cm the vertical displacement decreased by 18%, 24%, and 37% respectively.

Elastic characteristics of the underrail base of a ballastless railway track

Objective: Experimental determination track modulus and the coeffi cient of relative stiffness of underrail base and the rail, which are the main elastic characteristics that determine the stresses in the structural elements of track superstructure under the impact force from the train. The values of these parameters for a track with a ballast layer are well studied, in contrast to a ballastless track. Comparison of the elastic characteristics of a ballastless railway track with analogs of a track on ballast, as well as an assessment of their effect on the stress-strain state of the superstructure elements of a ballastless track. Methods: When carrying out full-scale tests, strain-gauge methods for measuring stresses in the elements of the track superstructure were used. The obtained values were processed by the methods of mathematical statistics. One statistical series included the values of stresses corresponding to one type of rolling stock, fi xed axle load and train speed, changing by no more than 10 km/h. The probability level in processing the results was taken in all cases equal to 0,994. Results: The values of track modulus and the coeffi cient of the relative stiffness of the underrail base and the rail were obtained for a ballastless structure of the RHEDA 2000 type. Practical importance: The results allow us to consider the rail as a beam lying on a solid elastic foundation in relation to the ballastless track and use the existing calculation methods for the design of ballastless track structures depending on the operating conditions.

Structure–Elastic Properties Relationships in Gelling Carrageenans

Gelling carrageenans are polysaccharides extracted from the Gigartinales order of red algae. These are additives used essentially in the food industry for texturizing, stabilizing or gelling various formulations. Although a consensual gel mechanism has been reached which encompasses a coil-to-helix transition followed by the self-assembling of helices in a network, the structure–elastic relationships in the network are still to be clearly established. This paper reviews the reports in which carrageenan gel structures have been systematically compared with gel elastic properties. The focus is on the sizes documented for structural units, such as strands, aggregates, voids or network meshes, as well as on the reported linear and nonlinear elastic characteristics. The insufficient rationalization of carrageenan gel elasticity by models which take on board mechanically relevant structural features is underlined. After introducing selected linear and nonlinear elastic models, preliminary results comparing such models to structural and rheological data are presented. In particular, the concentration scaling of the strain hardening exhibited by two types of carrageenan gels is discussed.

Simulation of characteristics of composite material with «liquid» matrix

A theoretical model of composite material consisting of a fibrous reinforcing filler, epoxy and elastomer matrices is proposed. The main purpose of the elastomer matrix is relaxation of all stresses occurring under loading and blocking the crack growth. Such elastomer matrices were named as «liquid». The calculation of the stress-strain state of the developed composite material with «liquid» matrix was carried out by using the finite-element software Ansys. It was found out that when elastic characteristics of used elestomers were less, the level of maximal stresses was less and the load factor values were higher. Decreasing stresses results in the blocking of crack growth that leads to increasing durability of such materials.