Journal of Mechatronics and Artificial Intelligence in Engineering
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The vibration of a thermoelastic nanobeam due to thermo-electrical effect of graphene nano-strip under Green-Naghdi type-II model
Get PDFIn this paper, a new analysis of thermoelastic, homogeneous, and isotropic nanobeams has been constructed in the context of the Green-Naghdi type-II heat conduction law. The first end of the nanobeam is based on a graphene strip, which contains an electrical current with a small voltage which is a novel application. Under simply supported boundary conditions with fixed side ratios, the nanobeam has been thermally loaded with a heat source due to the thermal effect of the electrical current. On the time variable, the Laplace transform technique was utilized to solve the governing differential equations. The solutions were computed in the Laplace transform’s domain. Tzou’s approximation technique based on an iteration formula was used to calculate the Laplace transform inversions numerically. The numerical findings for various values of the electrical voltage and electrical resistivity of the graphene nano-strip have been displayed using graphs illustrating distinct scenarios. All the nanobeam’s researched functionalities have been reported to be influenced by electrical voltage and electrical resistivity. The electrical voltage and resistivity of a graphene nano-strip might be utilized as a tuner to regulate the nanobeam's vibration and energy
Propagation characteristics of vibrations due to rock blasting in silt-rock strata
Get PDFThe geological effects of rock blasting in silt-rock strata are complex, and the vibrations caused by the blasting threaten the safety of inhabitable areas. Based on measured data for the vibrations at the site and dynamic finite element simulations, the propagation characteristics of vibrations in silt-rock strata were studied. The propagation of the vibrations of the surface, the propagation characteristics of the vertical vibration velocities from the surface to the tunnel, and the attenuation of the blasting vibrations along the tunnel’s axis were analyzed. The results of this study are as followings: in the direction of the tunnel’s axis and in the direction vertical to the tunnel’s axis, the peak particle velocities (PPVs) of the surface decreases with increasing horizontal distance from the explosion source. The magnitudes of the PPVs of the surface under five working conditions are the same when the surface particle is right above the center of the explosion source and 10 m away from the center. In the vertical direction from the surface to the explosion source, the vertical direction of the silt-rock strata and the vertical direction of the silt stratum, the PPVs increases gradually with the increasing distance from the surface in the vertical direction. The change in the thickness of the artificial fill and silt in the shield interval strata has little effect on the PPVs along the tunnel’s axis. The results of this study provide a reference for identifying the safety distance around the inhabitable areas of rock blasting under similar geological conditions
Using total equivalent temperature difference approach to estimate air conditioning cooling load in buildings
Get PDFThe objective of this study is to provide a simplified worksheet based on the Total Equivalent Temperature Difference (TETD) Approach to estimate a building’s cooling load under Iraqi climate conditions. The heating, ventilation and air conditioning (HVAC) system was applied to scientific laboratories at the College of Engineering, University of Warith Al-Anbiyaa, Karbala, Iraq. The study estimates the cooling load of the building, which consists of 10 zones. Cooling load elements such as ventilation, lighting, walls, floors, roofs, windows, infiltration, and human factors were considered. The worksheet provides an appropriate alternative for easy and fast prediction within Iraq's climate conditions
Improved algorithm for a system with different stiffness for positive and negative displacements
Get PDFIn the process of investigation of dynamics of elements of robots, systems with different values of stiffness for positive and negative displacements play an important role. This change of the value of stiffness has an effect to the results of numerical calculation of dynamics of the system. For more precise investigation of dynamics a special numerical procedure is proposed in the paper. Numerical results for two values of time steps: large and medium ones, are presented for two cases: without application of the proposed procedure and with application of it. Comparison of the presented results indicates advantages of the proposed numerical procedure
Indoor and outdoor multi-source 3D data fusion method for ancient buildings
Get PDFAncient buildings carry important information, such as ancient politics, economy, culture, customs. However, with the course of time, ancient buildings are often damaged to different degrees, so the restoration of ancient buildings is of great importance from the historical point of view. There are three commonly used non-contact measurement methods, including UAV-based oblique photogrammetry, terrestrial laser scanning, and close-range photogrammetry. These methods can provide integrated three-dimensional surveys of open spaces, indoor and outdoor surfaces for ancient buildings. Theoretically, the combined use of the three measurement methods can provide 3D (three-dimensional) data support for the protection and repair of ancient buildings. However, data from the three methods need to be fused urgently, because if the image data is not used, it will lead to a lack of real and intuitive texture information, and if only image matching point clouds are used, their accuracy will be lower than that of terrestrial laser scanning point clouds, and it will also lead to a lack of digital expression for components with high indoor historical value of ancient buildings. Therefore, in this paper, a data fusion method is proposed to achieve multi-source and multi-scale 3D data fusion of indoor and outdoor surfaces. It takes the terrestrial laser point cloud as the core, and based on fine component texture features and building outline features, respectively, the ground close-range image matching point cloud and UAV oblique image matching point cloud are registered with the terrestrial laser point cloud. This method unifies the data from three measurements in the point cloud and realizes the high-precision fusion of these three data. Based on the indoor and outdoor 3D full-element point cloud formed by the proposed method, it will constitute a visual point cloud model in producing plans, elevations, sections, orthophotos, and other elements for the study of ancient buildings
Effect of warp and weft uniaxial tension on the permeability of sand covered with geotextile
Get PDFThe permeability of sand covered with geotextile is affected by the permeability of geotextile, which is related to the tensile state of the geotextile. Considering the weaving mode of geotextile, the effects of warp tension and weft tension on the permeability of sand covered with geotextile were studied by experiment. Four different specifications of geotextiles were selected for warp and weft tension respectively. The changes of permeability parameters of sand covered with geotextile under non tension, warp and weft tension were measured by vertical permeability instrument, and the effects of warp and weft tension on permeability parameters such as seepage velocity, sand loss and gradient ratio were analyzed. The test results show that the water permeability and anti silting performance of the geotextile increase with the increase of tensile strain, and the soil conservation performance decreases with the tensile strain increasing. Meanwhile, the relationship between permeability and warp tensile strain is not monotonic. When the warp tensile strain 3%, the water permeability and anti silting performance of geotextile are the weakest, and the soil conservation performance is the strongest
Greensand project – transport and offshore storage of CO2 in Denmark – status, outlook and challenges
Get PDFThe Greensand project includes, beside from safe and efficient geological offshore CO2 storage, offshore transport by ship and/or pipeline of CO2 from key side onshore facilities established to capture, liquefy, onshore transport and temporarily store the CO2 before offloading to storage site. The Greensand project builds on the usage of the offshore Siri complex sandstone reservoirs no longer in use for oil and gas production. The storage sites, offloading and injection systems and transportation means are currently being technically matured. The target is to be able to offer customers safe and reliable transport and storage services from the start of 2026. Currently meanwhile maturing a technical concept, commercial and regulatory activities are ongoing in parallel. The Greensand partners INEOS Energy and Wintershall Dea have also decided to perform an offshore pilot test of injecting liquified CO2 into a particular reservoir serving as candidate for future long terms storage of CO2. Along the pilot testing offshore project, material testing and deployment of monitoring techniques are being matured. The Pilot testing offshore planned to take place late 2022 with a 3-months duration
Modal analysis of a milling dynamometer considered as 1DOF system
Get PDFA force transducer-based plate dynamometer for milling force measurements is presented in this paper. The main components of the designed dynamometer were described, and experimental modal analysis was carried out while considering the dynamometer as a 1DOF system. The values of the main components of the 1DOF systems such as mass, damping coefficient, and equivalent stiffness were identified, and the natural frequency for rings and dynamometer was calculated. The calculated natural frequencies of components were found in reacceptance FRF, obtained by modal analysis done with an impact hammer. A MATLAB simulation was done to validate the system using the transfer function based on the modal test
Study on the extraction method of the friction-induced vibration signal of rotary compressors
Get PDFThe operation noise level of air conditioners has been a main concern to consumers. The friction-induced vibration and noise have a contribution to the overall operation noise level of air conditioners. In this paper, two rotary compressors were tested to measure the vibration and noise of the compressors. The friction-induced vibration signals were extracted using a combination of the harmonic wavelet transform and the envelope spectrum analysis. The two rotary compressors were disassembled to check whether the compressor parts have been worn after testing. Results show that when the crankshaft was worn, the friction-induced vibration of compressors is strong. At low rotational speeds of the rotary compressor, the friction-induced vibration is easily excited, which is probably attributed to the boundary lubrication at the interface between the crankshaft and bearing. At high rotational speeds of the rotary compressor, the friction-induced vibration is not easy to be excited, which is probably attributed to the aerodynamic lubrication at the interface between the crankshaft and bearing
The influence of the truss bar on the dynamic behavior of a Warren truss by changing the modulus of elasticity
Get PDFThe paper presents the natural frequencies shift of a Warren truss with seven elements in the case that members of the structure are weakened by considering that the modulus of elasticity with a lower value. Taking into consideration that the slenderness ratio has a constant value and the transverse section of the truss bars is changed, the relative frequency shift for the first seven vibration mode were calculated by using the values obtained from numerical modal analysis. The conclusions reveal the fact from the dynamic behavior of the structure it can be obtained templates to identify the weakened truss bar of the structure