The cost of road construction or its repair is among the most concerns for the pavements engineers. Cracking and degradation is common mode of failure in asphalt pavements that occurs due to increasing traffic loads or even environmental conditions. For facing with these damages, some solutions are proposed including correction, quality improvement and increasing the asphalt resistance. In this research, by adding different percent amounts of black nano-carbon and polyester fibers as modifier in the asphalt mixtures and conducting several Marshall tests, it was observed that adding these two additives can improve generally the Marshall results. Polyester fiber causes preventing crack and damages of asphalt because of armed effect specification. According to the results, Marshall stability is increased up to 61%. Furthermore, an economic analysis was performed to investigate the cost of using such modified asphalt mixtures for constructing 1 km of a six line road and suitable percentages of additives were found from mechanical-economic analyses.

Portland cement concrete (PCC) / asphalt concrete (AC) bonded components are seen in both conventional pavement structures as well as overlays. Due to the environmental and traffic loads, cracks occur at the interface of the PCC and AC layers and finally, may propagate through the interface or one of the layers. Therefore, the evaluation of bond strength between these layers is important. This paper investigates bond strength between asphalt concrete and Portland cement concrete using a new sandwich test specimen. The developed specimen, called Bi-material semi-circular bend (BSCB) is made of asphalt concrete and the Portland cement concrete, cracked at the interface of the materials. First, the suggested specimen is introduced and characterized using finite element simulation. Then, the specimen is employed to obtain bond strength between asphalt concrete and Portland cement concrete under mixed mode loading, and at two temperatures: -20C and 20C. The fracture toughness at different mixed mode conditions is obtained, and finally, fracture criterion for the tested bonded joints is presented.

Considering accurate constitutive models is of the utmost importance to capture mechanical response of soft tissue and biomedical materials under physiological loading conditions. This paper investigated the behaviour of porcine myocardium of passive rested hearts. This was investigated by applying biaxial loads on the myocardium. The main objective of this research was to investigate the cardiac mechanics of various regions in the healthy passive of a porcine. The biaxial mechanical properties of myocardial tissue samples were captured using a biaxial testing system. The porcine heart was divided into three regions, namely: left ventricle (LV), septum and right ventricle (RV). In these regions, 18×18 mm2 equal samples were cut from six porcine passive hearts. For the LV sample, biaxial elastic modulus in the fibre direction is 33.3% larger than in the cross fibre direction. For the mid-wall sample, biaxial elastic modulus in the fibre direction is 18.8% larger than in the cross fibre direction. For the RV sample, biaxial elastic modulus in the fibre direction is 33.3% larger than in the cross fibre direction. It was concluded that the cardiac mechanics of LV, Septum and RV exhibit different mechanical behaviour. The mechanical behaviour exhibited by various regions (LV, Septum and RV) in the healthy porcine heart differs considerably. To develop adequate computational models, these data could be utilized to estimate the material parameters of the myocardium.

The linear elastic analysis of homogeneous, isotropic cracked bodies started in the 1900s. The existence of three dimensional corner point effects in the vicinity of a corner point where a crack front intersects a free surface was investigated in the late 1970s. An approximate solution by Bažant and Estenssoro explained some features of corner point effects but there were various paradoxes and inconsistencies. Results derived from finite element models showed that the analysis is incomplete. The stress field in the vicinity of a corner point appears to be the sum of two different singularities (i.e. stress intensity factors and corner point singularities). In this paper some recent results for the corner point singularities under in and out of plane loadings is reviewed and discussed.

This article discusses possibilities of application of widely applied and promoted abroad methods of active dampening of vibration and pressure oscillations (antinoise technology) in order to reduce vibration transfer via vibro-insulating couplings (compensators) of fluid pipelines. This is required in solution of issues of vibration insulation of equipment with regard to foundation and environment along pipelines with working mediums, for instance, in transporting of oil and gas, in energy and transport engineering. Reasonability of operation of active system in combination with means of passive dampening of these impacts is demonstrated. In terms of efficiency and minimum energy consumptions by active system it is reasonable to apply active dampening of vibration and oscillations downstream of the vibro-insulator (compensator) where their level is significantly lower than in the source. In the case of pipeline this implies dampening of vibration and oscillation downstream of compensator and damper, however, such works are nearly unavailable. This is attributed to significant coupling between vibration and pressure oscillation in compensator and pipeline itself, complicating solution of the problem. It is concluded that for efficient application of active dampening in pipeline compensators it is required to develop compensators with minimum coupling between vibration and oscillations.

An approximated crack growth direction and coalescence of the multiple cracks were obtained for an aluminum alloy plate by the finite element approach (FEA). Self-similar as well as non-self-similar crack growths were observed based on relative position of multiple cracks. The FE predictions of crack growth direction are validated with an experimental results and good agreement is established. Typical numerical results are presented to examine the effect of changing the crack tip distance (S), crack offset distance (H) on crack growth direction and coalescence of a finite aluminum alloy aluminum plate. Based on the analysis and experimental results, a new mathematical models for self-similar and non-self similar crack growth are introduc

Quality of blast preparation for rock beneficiation influences both on integrity of mineral stock in particular and in economical performances of enterprise operations in general. While rock processing for obtaining of crushed stone the yield of screenings is high, its amounts depend on rock strength properties. Investigation into the influence of drilling and blasting parameters on strength properties of blasted rocks is an urgent research and practical task for mining companies producing building stones. This article discusses results of full-scale experiment aimed at determination of strength of blasted rocks in shotpile with accounting for fracture zones as a function of rock massif saturation with energy of explosive substance.

In the present study, the flexural behavior of concrete beams reinforced with longitudinal rebars made of glass fiber reinforced polymer composites (GFRP), is studied using finite element method. For this purpose, a number of concrete beams with square sections are modeled in ABAQUS. In all of the beams, four GFRP rebars with diameter of 12 mm, and 10 steel rebars with diameter of 8 mm are vertically used to prevent creating shear cracks in the beams. The beam no. 1 is without transverse rebar, beam no. 2 has a row of transverse rebar, which is placed at the bottom and in the plane of vertical rebars. Beam no. 3 has a row of transverse rebars that is placed at the top and in the plane of vertical rebars; and the beam no. 4 has two rows of transverse rebar at the top and bottom of the beam in the plane of vertical rebars. The beams are gradually loaded under up to 6 ton, and the amounts of displacement and strain at the middle of beams are compared together. The obtained results reveal that the force-displacement diagram of reinforced beams with composite rebars are almost linear until ultimate phase, and in all of the beams, adding transverse rebar leads to less deflection in the middle of the beam under an identical loading. Moreover, the load bearing capacity of beams containing transverse rebars, were higher than the other beams.

The present invention provides a modular drilling assembly having a module for contactless power and data transfer over a nonconductive gap between rotating and non-rotating members of a steering module. The gap usually application data contains a non-conductive fluid, such as drilling fluid, or oil for operating hydraulic devices in the down-hole tool. The down-hole tool in one embodiment is a modular drilling assembly wherein a drive shaft is rotated by a down-hole motor to rotate a drill bit attached to the bottom end of the drive shaft. Generally, there are two main sections on mud motor which are bearing section and power section. The power section generally includes a housing which houses a motor stator within which a motor rotor is rotationally mounted. The power section converts hydraulic energy into rotational energy by reverse application of the Moineau pump principle. The stator has a plurality of helical lobes which define a corresponding number of helical cavities. The rotor has a plurality of lobes which number one fewer than the stator lobes and which define a corresponding plurality of helical cavities. Generally, the greater the number of lobes on the rotor and stator, the greater the torque generated by the motor. Fewer lobes will generate less torque but will permit the rotor to rotate at a higher speed. Based on torque and rotate speed, determine the optimum power can be produced by power section configurations.

In recent years, efforts have been made to produce advanced composite materials in order to lessen environmental impact and to extent sustainability. Traditional materials are largely substituted by composites due to their greater properties like flexural strength, low thermal expansion and high strength. Numerous studies are present that show the process of composite materials reinforcement with natural fiber to improve mechanical and thermal properties. The vital aspect of exploitation of natural fiber in composites is associated with biodegradability. An extensive range of different natural fibers has been used for reinforcement till now. In present work, mechanical properties of jute fiber reinforced epoxy and polyester composites manufactured using Taguchi optimization method are investigated, experimentally. It was found that jute reinforced epoxy composite had better mechanical properties than jute polyester composite. Also, Epoxy- jute composite had lower erosion wear rate than polyester jute composites.