Shaft Model Research Articles

Numerical Modelling of a Void Behind Shaft Lining using FDM with a Concrete Spalling Algorithm

Purpose The aim of the research presented in this paper was to determine the impact of voids behind the lining on shaft stability. Methods This paper presents an example of extending the FLAC3D with the possibility of the simulation of concrete detachment and separation under specific conditions by means of a developed FISH routine. Results The appearance of voids and cavities behind the lining has been repeatedly observed in active shafts in Polish coal mines and can lead to the emergence of tensile forces in the lining. The study included 366 models of shafts using the rock mass properties of typical shale stone, coal, and sandstone found in the Upper Silesian Coal. Practical implications he presented concrete spalling algorithm may be used, especially, for the stability evaluation of locally damaged shaft lining or when there is a suspicion of void behind the lining. Originality/value An important limitation of all continuous methods is the inability (except when using some additional tools) to simulate the rotations of predefined elements (blocks) and their separation from the rest of the object. The concrete spalling algorithm presented extends the capabilities of FLAC3D with the possibility of simulating the detachment and separation of destroyed lining fragments.

Design and Analysis of Rotor Assembly of Hammer Mill Machine`

The project deals with the Manufacturing with Design and Analysis of Hammer Mill Machine and Rotor Assembly of Machine of Capacity of 200 Kg/hr. Which is due to providing the transmission power of 5 HP to the machine.
 In this project, the Hammer mill machine body structure, Angle Frame and foundation frame for machine is designed using Catia. Also each and every part or component is required for machine is designed. In the present work by using standard design procedures, Diameter of the rotor of shaft of machine has been designed. Theoretical calculations done by using PTC Mathcad software for new learning experience and ease. When the shaft of the rotor is rotated at the given speed (rpm i.e. 1728 rpm) and the load applied to the shaft it should not bend during rotation. When the shaft is rotated under free conditions deflections will be created due to critical speed of the shaft.
 After Designing process, some of required drawings are converted into Ansys supported format i.e. drawings are imported into Ansys for further analysis. Meshing of the shaft model was done and the loads, stresses that were applied for the shaft to be checked out that the design should be safe one. The design should be safe when the values obtained from the design procedure were compared with the standard values and result obtained from the analysis using Ansys.
 As per the designing, the required parts are fabricated such as side plates, bearing support, doors, hinge supports by using conventional methods like gas cutting, welding, drilling, shaft turning, slotting, milling, etc. and some hardware materials buy from stores which is used for further assembly process. At the final step all parts are assembled according as per requirements. At the end actual capacity of machine is calculated by using conventional method.

Analysis of earth pressure distribution on deep circular shafts in composite geological strata using centrifuge modelling

With the rapid development of urban underground space, the depth of working shaft has been gradually becoming deeper to accommodate the underground construction needs. The existing studies for earth pressure distribution of shafts are mainly focused on sandy soils within 30 m. There is a strong need to investigate the earth pressure distribution on deep shafts (more than 30 m) in complicated soil conditions using centrifuge modelling to fill the knowledge gap and provide experimental basis for design. In this paper, geotechnical centrifuge modelling was used to investigate the earth pressure distribution along deep circular shaft structures (with a depth of 100 m) in composite geological strata. Three centrifuge tests on model shafts in layered ground with different thickness of clay and sand were carried out, respectively. Drainage method was used in the experiment to simulate the unloading effect caused by excavation of soils inside the shaft model. The earth pressure distributions along the shaft lining before and after the excavation were investigated. The results were analysed and compared with other existing earth pressure theories. This research provides valuable insights for earth pressure distribution for design of circular deep shafts (e.g. 100 m) in composite geological strata.

Numerical studies on swirling of internal fire whirls with experimental justifications

Numerical studies on internal fire whirls (IFW) generated in a vertical shaft model with a single corner gap were reported in this paper. The generation of IFW, burning rate of fuel and temperature were studied experimentally first. Numerical simulations on medium-scale IFW were carried out using a fully-coupled large eddy simulation incorporating subgrid scale turbulence and a fire source with heat release rates compiled from experimental results. Typical transient flame shape was studied and then simulated numerically by using temperature. The dynamic phenomena of generation and development of IFW were simulated and then compared with experimental results. The predicted results were validated by comparing with experimental data, which demonstrated that an IFW can be simulated by Computational Fluid Dynamics. Numerical results for flame surface, temperature, and flame length agreed well with the experimental results. The IFW flame region and intermittent region were longer than those for an ordinary pool fire. The modified empirical formula for centerline temperature was derived. Variations of vertical and tangential velocity in axial and radial directions were also shown. The vortex core radius was found to be determined by the fuel bed size. Velocity field was not measured extensively due to resources limitation. Comparing measured temperature distribution with predictions is acceptable because temperature is related to the heat release rate, air flow and pressure gradient.

Analysis on the Influence of Shaft and Cross Passage Turn to the Main Line of Ingate under Different Construction Schemes

In the weak stratum, the construction of ingate is a key technical problem at the place where the shaft and cross passage turn to the tunnel. Based on Lanzhou Metro, the corresponding changes to the construction plan of the ingate of the section tunnel were made. Finite element software is used to carry out three-dimensional modeling and design of subway shaft, cross passage, and tunnel structures in connected sections. The influence of the two construction schemes on surface settlement, deformation, and stress of tunnel support structure and stress conversion of ingate are compared, as well as the fitting degree between numerical simulation results and field monitoring data. Finally, the optimal scheme and key points of construction control are determined. The results show that the optimization scheme has obvious advantages in the control of surface settlement and the deformation of shaft and cross passage support. However, the difference between the stress and deformation of the tunnel supporting structure and the original plan is not obvious. Since the project focuses on shaft, cross passage, and tunnel connection section, the changed construction scheme is better.

Micro Hierarchical Structure and Mechanical Property of Sparrow Hawk (Accipiter nisus) Feather Shaf

In this study, the real 3D model of the feather shaft that is composed of medulla and cortex is characterized by X-ray computer tomography, and the structural features are quantitatively analyzed. Compression and tensile tests are conducted to evaluate the mechanical performance of the feather shaft and cortex at different regions. The analysis of the 3D model shows that the medulla accounts for ∼70% of the shaft volume and exhibits a closed-cell foam-like structure, with a porosity of 59%. The cells in the medulla show dodecahedron and decahedron morphology and have an equivalent diameter of ∼30 μm. In axial compression, the presence of medulla enhances the shaft stability. Especially, the combined effect of the medulla and cortex increases the buckling strength of the middle and distal shaft by 77% and 141%, respectively, compared to the calculated value of the shaft using linear mixed rule. The tensile properties of the cortex along the shaft axis are anisotropic because of the different fiber structures. As the fiber orientation gradually becomes uniform in the axial direction, the Young’s modulus and tensile strength of the cortex on the dorsal gradually increase from calamus to the distal shaft, and the fracture mode changes from tortuous fracture to V-shaped fracture. The cortex on the lateral shows the opposite trend, that is the distal shaft becomes weaker due to fiber tangles.

Study on failure of transmission shaft based on finite element and fracture analysis technology

Due to the harsh driving environment, the power transmission components of military vehicles are subjected to long-term alternating loads and sudden impact loads. A failure analysis of the transmission shaft of a military truck was carried out. By constructing a mechanical simulation analysis model of the transmission shaft, the dynamic response of the structure under alternating stress and impact load is solved. Then the cause and mechanism of drive shaft failure were analyzed. Using fracture analysis technology to discuss the phenomenon of bearing sleeve cracking, circlip rupture and flange fork deformation. It indicates that caused by overload, foreign matter between the shaft and the needle etc., which ultimately leads to the failure of the universal joint transmission. Finally, the optimal design of the drive shaft is proposed.

Observation on a fire whirl in a vertical shaft using high-speed camera and associated correlation derived

The fire whirl generated by burning a pool fire in a vertical shaft with a single corner gap of appropriate width was studied using a high-speed camera. A 7 cm diameter pool propanol fire with heat release rate 1.6 kW in free space was burnt inside a 145 cm tall vertical shaft model with gap widths lying between 2 cm and 16 cm. The flame height was between 0.25 m and 0.85 m for different gap widths. Photographs taken using a high-speed camera at critical times of swirling motion development were used to compare with those taken using a normal camera. From the experimental observations on flame swirling by a high-speed camera, stages for generating the fire whirl were identified much more accurately. Two flame vortex tubes moving over the horizontal burning surface of the liquid pool were observed. Based on these observations a set of more detailed schematic diagrams on the swirling motion was constructed. From the observed flame heights under different gap widths and using three assumptions on the variation of air entrainment velocity with height, an empirical expression relating the burning rate with flame height and the corner gap width was derived from the observation with high-speed camera. The correlation expression of the burning rate of the pool fire obtained would be useful in fire safety design in vertical shafts of tall buildings.

Design and Analysis of Rotor Assembly of Hammer Mill Machine

The project deals with the Manufacturing with Design and Analysis of Hammer Mill Machine and Rotor Assembly of Machine of Capacity of 200 Kg/hr. Which is due to providing the transmission power of 5 HP to the machine. In this project, the Hammer mill machine body structure, Angle Frame and foundation frame for machine is designed using Catia. Also each and every part or component is required for machine is designed. In the present work by using standard design procedures, Diameter of the rotor of shaft of machine has been designed. Theoretical calculations done by using PTC Mathcad software for new learning experience and ease. When the shaft of the rotor is rotated at the given speed (rpm i.e. 1728 rpm) and the load applied to the shaft it should not bend during rotation. When the shaft is rotated under free conditions deflections will be created due to critical speed of the shaft. After Designing process, some of required drawings are converted into Ansys supported format i.e. drawings are imported into Ansys for further analysis. Meshing of the shaft model was done and the loads, stresses that were applied for the shaft to be checked out that the design should be safe one. The design should be safe when the values obtained from the design procedure were compared with the standard values and result obtained from the analysis using Ansys. As per the designing, the required parts are fabricated such as side plates, bearing support, doors, hinge supports by using conventional methods like gas cutting, welding, drilling, shaft turning, slotting, milling, etc. and some hardware materials buy from stores which is used for further assembly process. At the final step all parts are assembled according as per requirements. At the end actual capacity of machine is calculated by using conventional method.

Strength analysis of a propulsion shaft dedicated for the main rotor test bench

This article presents the strength analysis of various drive shaft concepts for the test stand for research of aircraft’s main rotors. The results of stress analysis for conceptual shaft models are presented. A technological solution was developed on the basis of the obtained results to meet the design requirements and reduce the impact of maximum stress to a minimum. The aim of the study was to develop a design solution for a propulsion shaft research allowing for the most optimal way of conducting the research installation from a stationary to a rotary system (data and power collector system).

Active magnetic dampers for controlling lateral rotor vibration in high-speed rotating shafts

High-speed rotating machinery frequently operates supercritically, traversing self-excited resonance during startup and shutdown. The rotor's peak radial displacement often occurs during this critical transition, thus defining minimum clearances between the rotor and stator. Squeeze film dampers (SFDs) are frequently used to reduce lateral rotor vibration (LRV), but their passive nature imposes design and performance limitations. An alternate approach, the subject of this paper, employs active magnetic dampers (AMDs) to overcome the inherent tradeoffs associated with squeeze film dampers. This paper details the design, fabrication and experimental demonstration of an AMD for reducing LRV in a high-speed rotating shaft through its critical speed. A finite-element method (FEM) model of a high-speed flexible shaft with an AMD mounted proximal to a compliant bearing support is developed and parameterized using test data. Different actuator locations are evaluated using the FEM model, revealing that the primary mechanism for LRV reduction is the moment exerted about the compliant bearing. Performance of a SFD is simulated for comparison, revealing that the AMD more effectively reduces LRV. Peak radial deflection is reduced by an average of 79% through the shaft's first critical speed.

Alignment optimization of 3D model of propulsion shaft system

Three dimensions models of propulsion shafts are presented in this work. A shaft alignment optimization is computed for a crankshaft, intermediate shaft and propeller shaft. “Design Study” sensors are used to report the best solutions of bearing reactions according to the vertical displacement. Shear forces and bending moments are listed for the flanges. The finite element analysis investigated a slope and deflection of the propulsion shaft system. Pictures of stress and displacement of the shafts, bolts and flanges are pointed in the paper. Stress concentrations and a factor of safety is calculated in the 3D dimension.

Theoretical modelling and analysis of a four-wheeler crank shaft by different aluminum alloys

Crankshaft used to transform the give back movement of piston into spinning movement. Crankshaft has a shaft component which resonate inside number one bearings, crankpins to huge ends of connecting rod are related, crank palms or web which attach the crankpins and shaft factors. The crankshafts are experience to surprise and also fatigue masses. This fabric of crankshaft needs to hard and also fatigue resistant. Common place substances used in the crankshaft are Carbon Steel or Nickel-Chrome-Moly amalgam steel or Nickel-Chrome or explicit cast-iron. Aim of the task to format and production of crankshaft to a four-cylinder IC engine with the aid of the manner of using theoretical calculations in format vicinity for Aluminum alloys6061 and business enterprise grade. A 2dimensional drawing is drafted for crankshaft through the calculations and 3-D version is created inside the three-D modeling software utility software program.

Deformation Analysis of Internal Fixation Plate on Femur Bone Fracture: A Study Case on Local Raw

In the case of femur bone fracture, internal fixation is usually applied for the treatment due to the convenience and amenities of follow-up care. Due to a high demand for internal fixation implants in Indonesia, causing Pelopor Teknologi Implantindo Inc. (PTI Inc., Mojokerto - Indonesia) produces conventional implant material made from annealed local raw material of 316L stainless steel, with a yield strength of 317 MPa and ultimate tensile strength of 580 MPa. Compared to implant material in ASTM F138, it has a little higher value of both yield and ultimate tensile strength. To determine the effects of material type, normal stresses will be used to evaluate the fractured bone, while von Mises stresses will be used to analyze the strength of fixation plate. Besides, influence of material variation to the bone healing process is also discussed. Transversal-type fracture is chosen for fracture modeling of femoral shaft. The loading is taken from body weight of Asians, which is applied at femur head. The simulation result indicates that in the case of conventional fixation plate, there is no significant influence on the bone healing caused by different material type.

Research on aerodynamic and flow field characteristics of high speed elevator with different shaft blockage ratio

With the increase of building height, more and more high-speed elevators are applied to high-rise buildings in order to improve the transportation efficiency of people in buildings. Compared with the medium and low speed elevators, the airflow in the shaft is more severe when the high-speed elevator car is running in the narrow and long shaft, and the influence of aerodynamic force and aerodynamic noise is more obvious. In order to explore the aerodynamic characteristics of the high-speed movement of the elevator car and the airflow law in the shaft, and further optimize the aerodynamic parameters of the high-speed elevator shaft system, a full-scale three-dimensional model of the shaft with different blocking ratio is established and numerically simulated. Through the analysis of the calculation results of different blockage ratio of the shaft model, it is found that the greater the blockage ratio is, the greater the resistance of the car operation is, and the airflow disturbance behind the car movement is more severe than that in the front. The calculation results provide a reference for further exploring the airflow flow law in the high-speed elevator shaft.

Modelling and analysis of viscoelastic laminated composite shaft: an operator-based finite element approach

The main purpose of this paper is to perform dynamic analysis of a viscoelastic laminated composite rotor shaft considering various asymmetries. Equivalent modulus theory (EMT) is employed to derive the finite element based mathematical model of the composite shaft considering the shear effect and compared with other method known as direct procedure technique (DPT). The material damping behaviour of the composite shaft is incorporated using operator-based approach, which leads to a higher-order model. Fibre-reinforced composite sample of single layer and 8 layer are fabricated and tested in dynamic mechanical analyser to obtain frequency-dependent material data and viscoelastic parameters. EMT uses single layer properties, while modelling of DPT is done considering equivalent 8 layer sample. The closeness of numerical results between two methods proves the authentication of the applied EMT for modelling of damped heterogeneous laminated composite shaft.

Fatigue evaluation of TC17 titanium alloy shaft with surface scratch based on FEA and fracture mechanics

With the development of advanced mechanical equipment, more attention should be paid to the fatigue evaluation of the critical components affect by surface scratch, like the TC17 titanium alloy shaft. The designed fatigue test is carried out to reveal the negative effect of surface scratch on fatigue failure, and the fatigue limit model for TC17 titanium alloy with surface scratch is proposed based on the Murakami equation. Then, FEA with different surface scratches for TC17 titanium alloy shaft is carried out, an empirical formula is proposed to express the relationship between the stress and surface scratch. In addition, the unknown parameter related to TC17 and the specific stress intensity factor model is identified, to estimate the critical surface scratch of TC17 titanium alloy shaft. With the comprehensive application of the classic theory and new proposed models, a new fatigue life evaluation model of TC17 titanium alloy shaft with surface scratch is developed and verified, whcih is novel and essential to the maintenance of the damaged TC17 titanium alloy shaft.

Influence of antibiotic pellets on pore size and shear stress resistance of impacted native and thermodisinfected cancellous bone: An in vitro femoral impaction bone grafting model

IntroductionMorphology and mechanic properties of impacted cancellous bone are affected by carrier substances which provide high local concentrations of antibiotics. MethodsBone chips were taken from the femoral head of 6–7 months old piglets. One half was thermodisinfected and the other remained native. Ten specimens each were mixed with Herafill® antibiotic pellets and a control group of each 10 specimens respectively was examined. The cancellous bone was impacted according to Exeter technique and the implants were cemented. The distribution of the particles and the pores were defined with three dimensional computertomographic scan and shear force resistance was measured until failure. ResultsShear force resistance was not measured significantly less for thermodisinfected (2.7 Nm) compared with native bone (3.5 Nm) and addition of antibiotic pellets reduced shear force resistance in both groups since this was significant for the native group. The average pore volume of the native bone specimens appeared significant smaller compared to the thermodisinfected group (p = 0.011) and the pore volume showed a negative correlation with shear force resistance (p = 0.044). Pore volume around the pellets was found significantly increased and it appeared smaller for native bone. The number of pellets located next to the implant showed a negative correlation with shear force resistance (p = 0.034) and the negative correlation increased for pellets below the tip of the shaft model (p = 0.024). ConclusionAdding antibiotic pellets to native and thermodisinfected impacted cancellous bone increased pore volume since the area around the pellets showed increased porosity which correlated with reduced shear force resistance. Computertomographic three dimensional measurement of porosity might predict shear force resistance of impacted cancellous bone and improve impaction of bone grafting intraoperatively.

Operator based finite element modelling of viscoelastic cracked propeller shaft: a comparative study

The present study focuses on to explore the dynamic analysis of a viscoelastic propeller-shaft system with transverse breathing crack supported by journal bearings. Finite element modelling of the shaft continuum is done considering the Euler-Bernoulli beam theory. Operator based constitutive relationship is applied to incorporate material damping of the rotor and higher-order equations of motion are established. Accurate time-dependent functions are used to formulate cracked element stiffness matrix and augmented to the overall stiffness matrix of the entire system. Eigen analysis is performed after converting the higher-order equation into the first-order form. A Comparative study is demonstrated based on different dynamic parameters like whirl frequency, modal damping factor and stability limit of spin speed. Further, the variation of stability limit of spin speed and natural frequency is also studied based on the parameters such as crack depth and its location along different section of the propeller shaft.

Vibration modeling of wind turbine shaft as rigid shaft supported by EHL contact ball bearings with overhung disc system

An investigation into the dynamic behavior of Elastohydrodynamic Lubricated (EHL) angular contact ball bearings employed in wind turbines is given in this paper considering non-linear contact characteristics due to combined dynamic loads, different rotation speeds, hydrodynamic effects and load-deformation relation. In order to investigate the dynamic behavior of shaft-bearing system, a rigid shaft with overhung disk which is supported by a couple of EHL angular contact ball bearings is modeled as a 5 DoF nonlinear system.The contact between the rolling element and running surfaces in the bearing is modeled as an equivalent spring and damper. Hertz contact theory and EHL theory are used to obtain EHL contact characteristics and contact forces. Simplified rolling contact theory is used and pure rolling is assumed in the kinematic analysis. The contact angle and mutual approach of rolling elements are obtained analytically. The contact forces and film thickness are calculated iteratively for the quasi-static case using the Newton–Raphson method. In order to express the dynamic behavior of the system, nonlinear equations of motion are solved by a numerical method using Runge Kutta algorithm. The results indicate that the stiffness in EHL contact increases with the increase in load, the damping decreases with the increase in speed, the vibration behavior of the system is more complicated than the dry contact as the natural frequencies are now dependent on system running speed. It has also been observed that there is a significant decrease in vibration amplitude of the system under lubricated contact conditions as well as the frequencies.