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Item type:Publication, Access status: without files , Reference model of a mechanical billiard playing system for an agile large-scale student design project(American Institute of Physics (AIP), 2024-12); ; ; ; The education of engineering students requires practical projects that promote teamwork and technical understanding. Mechanical systems, such as a billiard-playing system, offer a unique opportunity to convey complex design principles engagingly. This work describes a reference model development for a system integrated into an agile large-scale student project. The aim is to support and accelerate learning in mechanics, precision engineering, manufacturing, and project management. A comprehensive project requirements analysis led to a development process involving concept development, detailing, and prototyping. The design maximizes the use of mechanical components, acknowledging the mechanical engineering background of most students with limited experience in electronics and software. The developed prototypes feature precise motion mechanisms and electrical controls with an ESP 32. Experiments focused on measuring precision and repeatability, confirming the approach's feasibility. The modular prototypes consist of a main platform, drive unit, Blackbox for electronics, and a height adjustment and tilt module, connecting to a hit unit. The system operates as a small omnidirectional mobile robot on the billiard table. The project methodology includes iterative design cycles, where student groups are responsible for design improvements. The reference model enables students to build on previous progress, developing new versions faster and fostering continuous improvement, with the results of these improvements being evaluated in a competition. Organizational measures address scalability challenges. Future work should focus on integrating the system into the curriculum and distributing the developed modules among student groups.Publicationtype: Conference Paper34 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Discrete crack propagation analysis of reinforced concrete beams under shear(2023-06-12); The investigation of crack growth in concrete structures without shear reinforcement is an active field of research for decades. To date, there is no consensus on the influence of the critical shear crack and its contribution to the shear force transfer, so that numerous shear force models take its magnitude differently. While one group assigns the largest amount mainly to the compression zone and less to the crack friction, the other group assigns it to the crack force transmission due to aggregate interlock. This paper presents an investigation of the influence of the critical shear crack on the load-bearing behavior of concrete beams without stirrups based on a discrete analysis using the extended finite element method (XFEM) for one or more discontinuities (cracks). The concrete damage plasticity (CDP) is used to represent a real material response. For the damage evolution of the discrete cracks, various softening models for the crack process zone are considered (linear, bilinear and nonlinear). The accuracy and computational intensities of different cases are compared. Based on experimental results, it is shown that XFEM in combination with CDP provides realistic data with respect to load-bearing behavior, stresses in the concrete model, crack propagation, crack kinematics, and resulting crack aggregate stresses.Publicationtype: Journal Article34 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Recent progress on geometrical and stress concentration characterization of welded jointsStress concentrations arise at welded joints due to local notches at weld transitions and determine fatigue life under cyclic loading. In order to accurately determine the severity of these stress concentrations from local weld geometry parameters advanced measurement technologies are required; however, the characterization of welded joints is traditionally based on manual measurements. In recent years, several techniques have been developed to characterize geometrical and stress concentration features of welded joints. This study briefly reviews a number of studies on weld geometry measurements, stress concentration characterization, and the determination of their influence on fatigue life estimation. Finally, an outlook on machine learning-based determination of fatigue life is given.Publicationtype: Conference Paper45 163 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A study on the wind blade performance using blade element momentum theory(American Institute of Physics (AIP), 2023); ; ; ; In this research paper, the aerodynamic performance of the blade of horizontal axis wind turbine has been investigated numerically based on the the Blade Element Momentum (BEM) method. The blade in this analysis is divided into several computational elements, where assumed no aerodynamic interaction between the elements. The primary objective is to analyze the blade performance under certain initial and boundary conditions. In addition to investigate the effect of geometrical parameters that include the radius of the blade tip, the blade twist, the lift-to-drag ratio and the induction factors as the primary dynamic parameters on the performance of the wind blade. It was determined the design parameters for a wind turbine that built using NACA4415 airfoil shape. It was found that the total thrust force, the total torque and the total power that would be generated by the selected wind turbine are 3739.5 N, 1827.0 N.m and 29.9 kW, respectively. The results also showed that reducing the number of blade elements results in an underestimation of the results based on aerodynamic predictions. Therefore, the number of blade elements needs to be adequately selected for reliable solution of BEM equations. It was found that the maximum value of the differential power along the radial position on the wind turbine span occurred at r/R=0.8. Furthermore, the maximum percentages of increment in the axial induction factor when change the radial position from the tip to the root of blade was 62%. While, for the tangential induction factor was decreased by 88% for the same change.Publicationtype: Conference Paper52 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Comparative on-grid solar systems winter performance analyses of different PV technologies in Baghdad weatherThe main aim of this research paper is to study and analyze the performance of three different types of Grid- Tied of Photo -Voltaic (PV) solar technology systems under Baghdad climate conditions in the winter season. The first one is Heterojunction with Intrinsic Thin layer (HIT) of 15 kWP, Copper Indium Gallium Selenide (CIGS) of 4.95 kWp and Monocrystalline Silicon (mono-Si) of 5.05 kWP that installed on the roof of the training and research office followed to the ministry of electricity and the two others installed in Mansour Factory. Where these systems are located in Iraq- Baghdad "latitude 33.3 °N, longitude 44.4 °E and 41 m above the sea level". The months to achieve the experimental work are January, February, and December of 2019. The highest values of daily energy produced for (HIT), (CIGS), and (mono-Si) in February were (77.35, 23.4, 22.58) kWh/day, respectively. While, the minimum values of energy produced in December by HIT, CIGS, and mono-Si were (48.58, 20.34, 16.86) kWh/day, respectively. It was found that the daily overall losses were higher in mono-Si in overall winter months, and maximum systems losses in December and minimum one in February. HIT Systems efficiency was higher than other systems and getting between February and December (14.65-12.97) % while (12.46-11.87) %, (10.49-9.19) % fo r CIGS and mono-Si systems respectively. The energy yield of HIT, CIGS, and Mono-Si systems varied in February and December between (5.24-3.29) kWh/kWp, (4.72-4.1) kWh/kWp, and (4.47-3.34) kWh/kWp, respectively. Performance ratio was higher in all months for CIGS systems that varied between (82.6-84) %.Publicationtype: Conference Paper52 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Vibro-acoustic amplitude and frequency modulations during fatigue damage evolution(2019-05-08); ; ; ; Vibro-Acoustic Modulation method (VAM) utilizes effect of the nonlinear interaction between higher frequency ultrasonic wave (carrier signal) and much lower frequency structural vibration (modulating signal). This interaction is taken place at the nonlinear interfaces (cracks, bolted connections, delaminations, etc.) manifesting itself in the spectrum as side-band components around the carrier. There are numerous studies applying VAM for nondestructive testing and structural health monitoring. Most of them utilize resonance structural bending vibrations as the modulating signal and measure a ratio of sideband to carrier spectral components defined as Modulation Index (MI). The present VAM study utilizes in-plane non-resonance very low frequency (10 Hz) tensile oscillations for monitoring fatigue and stress-corrosion damage evolution in steel. Experiments consistently demonstrated significant increase in MI during 70% - 80% of the fatigue life. Additionally, newly developed algorithm separates Amplitude and Frequency Modulations during the damage evolution demonstrating FM dominance at initial micro-crack growth stages and transition to AM dominance during macro-crack formation.Publicationtype: Conference Paper311 1 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Development of a colored GFRP with antistatic propertiesThis study shows that a modification with ultralow filler content of novel single wall carbon nanotubes (SWCNT) converts an intrinsic insulating GFRP into one with antistatic properties. These properties remain even by adding pigments for customizing without affecting the wanted bright coloring (e.g. signal color). We developed a bright colored and antistatic glass fiber reinforced polymer (GFRP) by addition of carbon nanoparticle and pigments. Novel, in industrial scale available SWCNT dispersed in polyester resin with low content of volatile organic compounds (VOC) show an ultra-low percolation threshold of 0.005wt.%. This ultralow filler content leads to the required conductivity as well as a given transparency of the nano composite. In a next step, we transferred these properties into a GFRP, manufactured by infusion process. The addition of pigments lead to the individual coloring of the GFRP. Both, the SWCNT modified and SWCNT colorized GFRP fulfilled the required electrical resistances for ESD protection.Publicationtype: Conference PaperScopus© Citations 2 509 749 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Development of a CSP plant energy yield calculation tool applying predictive models to analyze plant performance sensitivities(American Institute of Physics (AIP), 2017-06-27); ; ; At early project stages, the main CSP plant design parameters such as turbine capacity, solar field size, and thermal storage capacity are varied during the techno-economic optimization to determine most suitable plant configurations. In general, a typical meteorological year with at least hourly time resolution is used to analyze each plant configuration. Different software tools are available to simulate the annual energy yield. Software tools offering a thermodynamic modeling approach of the power block and the CSP thermal cycle, such as EBSILONProfessional®, allow a flexible definition of plant topologies. In EBSILON, the thermodynamic equilibrium for each time step is calculated iteratively (quasi steady state), which requires approximately 45 minutes to process one year with hourly time resolution. For better presentation of gradients, 10 min time resolution is recommended, which increases processing time by a factor of 5. Therefore, analyzing a large number of plant sensitivities, as required during the techno-economic optimization procedure, the detailed thermodynamic simulation approach becomes impracticable. Suntrace has developed an in-house CSP-Simulation tool (CSPsim), based on EBSILON and applying predictive models, to approximate the CSP plant performance for central receiver and parabolic trough technology. CSPsim significantly increases the speed of energy yield calculations by factor ≥ 35 and has automated the simulation run of all predefined design configurations in sequential order during the optimization procedure. To develop the predictive models, multiple linear regression techniques and Design of Experiment methods are applied. The annual energy yield and derived LCOE calculated by the predictive model deviates less than ±1.5 % from the thermodynamic simulation in EBSILON and effectively identifies the optimal range of main design parameters for further, more specific analysis.Publicationtype: Conference Paper258 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Recovery of rare earth elements (REEs) from uranium containing solutions using biosorption(American Institute of Physics (AIP), 2017); ; ; ; Batch testing and determination of appropriate biosorbent and experimental procedures for recovery of REEs from artificial solution as well as the efficiency of the process for recovery of REEs from artificial solution via biosorption are given in present research work.Publicationtype: Conference Paper246 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Chemical changes in polyetherimide (PEI) joined by friction-based injection clinching joining (F-ICJ) technique(American Institute of Physics (AIP), 2016-10-31); ; ; ; The study of new joining technologies for multimaterial structures is motivated by the environmental friendly policy of weight reduction in the automotive industry. Friction-based Injection Clinching Joining (F-ICJ) (European Patent Application EP 14182938.2) is a new staking-based joining technique, which uses frictional heating to produce joints in an energy-efficient and fast manner. In F-ICJ a non-consumable tool applies friction and force to soften or melt and deform a polymeric stud fitted in a through hole of a joining partner. After consolidation, the deformed stud (stake) mechanically joins the partners by creating a staked joint. The thermomechanical process exposes the polymer to high temperatures (250 - 290°C) and deformation rates resulting from the combination of tool rotational speeds of 8000-12000 rpm and short joining cycles (5-10 seconds). Resulting changes in material properties can affect the global performance of the joints. This study aims to investigate the chemical changes occurred in the polymeric partner of hybrid joints on polyetherimide (PEI) and aluminum 6082-T6. Molecular weight distribution (Size-Exclusion Chromatography - SEC) and chemical structure (Fourier transform infrared spectroscopy - FTIR) analyses were performed on the base material and PEI extracted from a joint to evidence any possible chemical changes caused by frictional heating. The polymeric sample from the joint showed number-average molecular weight (Mn) 23% smaller and weight-average molecular weight (Mw) 15% smaller than the PEI base material. FTIR spectra show reduction in the intensity of phthalimide bands owing to the F-ICJ process. Therefore, these analyses identified the extension of chain scission in the PEI caused by shear and heat imposed by F-ICJ process, which are fundamental for process optimization.Publicationtype: Conference Paper155