Trapezoidal Tooth Research Articles

Design and Simulation Study of Structural Parameters of Bionic Cutters for Tea Harvest Imitating Aeolesthes induta Newman

The cutter of the hand-held tea picker is the key cutting component in the efficient tea harvesting process. In order to solve the problems of large cutting resistance and uneven incision during tea picking, this study fully applied the bionics principle to combine the excellent cutting performance of Aeolesthes induta Newman’s mandibles with the tea cutter, which extracted and fitted the tooth profile structure curve of the upper edge of the Aeolesthes induta Newman’s mandibles. The trapezoidal teeth on the reciprocating cutter of ordinary hand-held tea-picking harvesters were optimized by the fitted curve, and a new tea cutter with the shape of Aeolesthes induta Newman teeth was obtained, which included four kinds of bionic tea-harvesting cutters. The multi-body system software ADAMS 2020 and finite element analysis software ANSYS 2024R1 were used to compare the kinematics, statics and explicit dynamics of cutting properties of the four bionic cutters and common cutters with ordinary trapezoidal teeth and saw teeth. The simulation results showed that the maximum equivalent elastic strain and the maximum cutting force during the cutting operation were reduced by 36.7% and 42.89%, respectively, for the cutting teeth of the bionic tea-harvesting cutter #4 compared with that of the cutter with ordinary trapezoidal teeth. The bionic tea-harvesting cutter designed in this study has better cutting performance than the cutter with traditional cutting teeth, which can effectively reduce the cutting force and improve the flatness and cutting quality of the cutting surface.

Design and Experiment Verification to Combined Dynamic Seal of Wide-Speed Hydraulic Motor Pump

To reduce the wear of lip seal of wide-speed hydraulic motor pump and prolong the service life, the lip compression is reduced and the non-contacting labyrinth seal is used as the front stage, forming a series combined dynamic seal (CDS). The reliability of CDS in the wide-speed range is verified by model experiment. Initially, the structure form and dimension of labyrinth seal with relatively small leakage and heat production were determined by model experiment. Then, by establishing the model of lip seal and simulating the static structure, the relationship between the compression and maximum contact pressure of the lip was obtained. Finally, using the CDS which is formed by combining the different lip seals with the selected labyrinth seal to carry out experiments, the leakage, temperature distribution and lip wear were obtained. The results show that trapezoidal tooth labyrinth seal (TTLS) has better sealing effect and less heat production. When the sealing clearance is 0.1 mm and 0.3 mm, it accounts for 0.11% and 0.32% of the rotor diameter, respectively. Under the same conditions, the smaller the proportion, the better the sealing effect, but the higher the heat production. With the increase of compression, the maximum sealing pressure first increases and then decreases. When the compression of the lip exceeds 0.1 mm, the CDS will not leak significantly in a wide-speed range, but the greater is the compression, the faster is the temperature rise in the closed cavity. Lip wear is positively correlated with pv and the wear decreases with the decrease of compression.

Magnetic field simulation and experimental investigation of magnetic fluid seal based on rotating shaft

Magnetic fluid seals are a new type of seal with zero leakage. Based on the requirements of the working conditions, a magnetic fluid seal device applicable to rotating shafts was designed in this study using magnetic field simulation analysis and experimental verification. The relationships between several structural variables and seal pressure were analyzed, and the fitting curve and equation were derived via fitting analysis. The magnetic field simulation results showed that sealing pressure decreased with an increase in the sealing gap, increased with the number of pole teeth, and increased and then decreased with an increase in the pole teeth angle. The trapezoidal pole teeth exhibited the best sealing performance. The experimental results showed that the best sealing performance was achieved when the amount of magnetic fluid was 3mL. The sealing pressure significantly decreased with an increase in the rotational speed.

Reinforced toothed belt of standard overall dimensions

A constructive modification of a standard toothed belt with a trapezoidal tooth profile is considered. Analytical dependencies are obtained and numerical analysis is performed for a specific size of the toothed belt. Keywords: toothed belt, modification, tooth profile, comparative analysis. shevchenko6-32@yandex.ru, mukhovatiy@mail.ru

Investigation on the generation of bevel gear by disk tool with curved tooth surface of trapezoidal tooth profile

A bevel gear pair with curved tooth surface is widely used for power transmission of intersecting shafts. The bevel gear pair with curved tooth surface has higher load bearing capacity than straight bevel gears, longer line length, quieter, center distance assembly error, and does not change the speed ratio. This paper proposes a disk cutter with curved tooth surface of trapezoidal tooth profile to generate a bevel gear pair. One continuously distributed a trapezoidal tooth profile with curved tooth surface on a disc into an imaginary disc cutter to generate a bevel gear pair with curved tooth surface. This method has never appeared in the literature. Therefore, a mathematical model of a disc cutter with curved tooth surface of trapezoidal tooth profile was established and used to generate the mathematical model of the bevel gear pair via the theory of gearing. Through the undercutting analysis, explore the undercutting conditions of the proposed disc cutter and determine the parameter size limit. Based on tooth contact analysis (TCA), the transmission error and the contact pattern of the bevel gear pair with curvilinear teeth is calculated under the assembly error of the bevel gear. The advantage of the proposed disc cutter is that the transmission error of the parabolic type without modification of the tooth surface of the bevel gear pair can be obtained.

Load-dependent stiffness model and experimental validation of four-station rotary tool holder

The four-station rotary tool holder is used to clamp multiple turning tools and realize automatic tool change on a lathe. For the accurate estimation of structural stiffness, a deeper understanding of mechanical behavior within locking tool holder is needed. This paper is the first attempt to introduce a theoretical vertical stiffness model of tool holder. The rough surface joint effect is characterized by fractal geometry theory, including lower-upper tool holder plane joint, gear plate joint with trapezoidal tooth, screw spiral surface joint. The interface base bulk stiffness and the support bearing deformation are also unified in the stiffness modeling. Through the force interaction, the nonlinear relationship of load–displacement is established. The bidirectional static loading test under various locking forces is conducted using a commercial tool holder. The different intercepts of load-dependent displacement curve for various preloads are experimentally captured. The vertical stiffness under compression load is higher than that under tensile load. The predicted values agree well with experimental results by the micro-topography characterization of surface joints. The numerical simulation shows that vertical stiffness increases with the increase of compression load, locking force, fractal parameter D, nominal area of surface joints, and the decrease of dragged load, fractal parameter G.

Высокоскоростное микрофрезерование деталей из композиционных материалов и алюминиевых сплавов

The paper deals with the design of the cutting part of complex-profile cutters with high productivity and surface quality. Numerical experiments carried out using the finite element method made it possible to determine the stresses and strains in the layer of the cut material when machining with multifaceted milling cutters of a new type and indirectly estimate the specific cutting forces. The required dimensions and shape of the cutting wedge are set with account for various geometric parameters of the cutting part, properties of the workpiece material, and cutting conditions. This made it possible to obtain a three-dimensional model of an end mill with a trapezoidal tooth and 700 cutting edges. Experimental studies also showed a change in the morphology of chips with a size of about 2 microns, which is in good agreement with the results of preliminary estimates by the finite element method. The productivity of processing with milling cutters of a new design can be improved by increasing the number of single cutting cycles up to4000–6000 s–1.

Shape Optimization of Discontinuous Armature Arrangement PMLSM for Reduction of Thrust Ripple

The aim of this paper is to present the optimal design process and an optimized model for a discontinuous armature arrangement permanent magnet linear synchronous motor (PMLSM). The stator tooth shapes are optimized to reduce detent force. When the shape of the stator is changed to reduce the detent force, the saturation magnetic flux density and the back electromotive force characteristics change. Multi-objective optimization is used to search for the local lowest point that can improve the detent force, saturation magnetic flux density, and back EMF characteristics. To reduce the detent force generated at the outlet edge, a trapezoidal auxiliary tooth was installed and the performance was analyzed. The experiment’s response surface methodology is used as an optimization method and all the experimental samples are obtained from finite-element analysis. The validity of this method is verified by comparing the optimized FEA model to the initial FEA model.

Arthroscopic Suture Anchor Design Finite Element Study

AIM: This in-vitro study investigated arthroscopic suture anchors’ main design parameters effect on surrounding bone. METHODS: Thirty-dimensional arthroscopic suture anchor designs’ models were created on engineering CAD software by changing thread profile, pitch, and anchor tip profile as design parameters. These models were imported into ANSYS Workbench for finite element analysis. Bone was simplified and modeled as two coaxial cylinders. Tensile vertical load of 300 N, and oblique at 45º to the vertical axis, were applied to each model as two loading conditions while the simplified bone base was fixed in place as a boundary condition. RESULTS: The finite element analyses on all models under both loading conditions showed stresses within physiological limits on bone. Trapezoidal teeth and inclined cut teeth designs showed the lowest values of stresses and deformations respectively on the bone under oblique loads, while curved tooth and square tooth designs showed the lowest values of stresses and deformations respectively on the bone under vertical loads. General ascending or descending trend was recorded by increasing pitch from 1.2 to 1.5 to 1.8 mm on the total deformation and maximum Von Mises stress on bone and anchor body. Tapered tip slightly increased bone and anchor stresses. CONCLUSION: Arthroscopic anchors thread profile has minor affect on cortical bone behavior. Trapezoidal teeth, square tooth, and inclined cut teeth profiles showed the lowest values of stresses and deformations on cortical bone. Increasing thread pitch of arthroscopic suture anchors increases or decreases stress on the bone, and anchor body according to thread profile edges. Anchor tip profile negligibly affects both deformations and stresses on bone and anchor body.

Experimental Investigation and Numerical Modelling of Flow Characteristics of Non-Rotating Twin Screw Model

Twin-screw pumps employ clearances between both screws and screw rotors and housing, which cause backflow as function of pressure differential. Reduction of this flow can be reached by proper geometry design. For the experimental investigation, the scaled model 1:2 of the screws section was produced with trapezoidal tooth profile in two modifications differing in tooth width and pitch. Measurement of flow characteristics of non-rotating twin-screw model was carried out for validation and possible corrections of the 3D CFD model. The testing was done with non-Newtonian liquid met in the food industry and additionally also with water. Experimental data were partly compared with results obtained from numerical simulations.

Experimental and numerical investigation for the geometrical parameters effect on the labyrinth-seal flow characteristics of fast reactor fuel assembly

The labyrinth seal is widely used in the fast reactor fuel assembly to control leakage flow rate, adjust pressure drop and cool assembly outer wall. In the current investigation, a new non-rotating labyrinth seal with right-angle trapezoidal throttle tooth is designed and manufactured, and its flow characteristics are experimentally and numerically investigated. Reynolds number from 61,512 to 81,261 is considered and experiment data were generated from hydraulic experiment conducted at constant water temperature (84 °C) in the labyrinth-seal test section. Numerical results with different turbulence model, wall-normal grid spacing, inlet turbulence intensity and stream-wise grid length are compared with experiment results to demonstrate the effectiveness of numerical simulation. Geometrical parameters have a significant effect on labyrinth-seal flow characteristics. Increasing throttle-tooth number, spacing and throttle-tooth thickness can improve the labyrinth-seal sealing performance, while increasing gap width influences the flow velocity limitation and increases the leakage. Labyrinth-seal resistance coefficient is validated to be independent of Reynolds number (61,512–81,261). It is deduced that the fully rough regime still exists in an annular-tube turbulence flow with high wall roughness. The energy dissipation caused by throttling effect, jet, vortex and secondary transverse turbulence is the main sealing mechanism. Moreover, a leakage-coefficient empirical correlation is obtained by regression analysis of experiment data, which can be used for the structure design of sodium-cooled fast reactor and preliminary estimation of leakage flow rate in similar non-rotating seals.

Development of Magnetorheological Brake with Tooth-Shaped Disc for Small Size Motorcycle

In this research, a new type of magneto-rheological brake (MRB) is proposed for small size motorcycle. The proposed MRB consists of a rotor with multiple trapezoidal teeth acting at multiple magnetic poles of the brake. In order to generate a magnetic field for controlling braking torque, a magnetic coil is placed on each side-housing of the brake. The inner face of each side-housing also has trapezoidal shape mating with the trapezoidal teeth of the rotor via MRF layer. By applying countercurrents to the coils, a magnetic fluid is generated with some magnetic flux going across the MRF layer (MRF duct) between the rotor teeth and their mating poles on the housing. By using multiple poles with trapezoidal shape, a high braking torque of the brake is expected while the size of the brake is still kept to be compacted. After an introduction about the development of MRBs in automotive engineering, the configuration of the proposed MRB is presented and its braking torque is derived based on Bingham rheological model of MRF. The proposed MRB is then optimally designed based on finite element analysis (FEA). Its optimized MRB is then manufactured and its braking performance is experimentally investigated. The MRB is then installed in a prototype motorcycle and the field test of this prototype motorcycle integrated with the MRB is then conducted.

Influence of tension layer quality on mechanical properties of timing belts

Reinforcement of the tooth belts is the element responsible for the transmission of the torque. Its structure is related to the dynamics of the belt and such important parameters as the stiffness of running stability on pulleys and above all, the pitch stability. The axis of symmetry of the reinforcement in the vertical direction of the belt is the reference point of the belt geometry as well as the neutral axis of stresses caused by bending. On the arc of the contact between belt and pulley, over the reinforcement, the belt is stretched, and below it is compressed. In the tooth belts, there are various solutions of the carrier layer, in terms of the materials used, but also types of fibers, quantity of the fibers, etc. The paper presents the results of analysis of the carrier layer of the most popular tooth belts with T10 and AT10 trapezoidal teeth. The paper shows possible direction of choice of the construction materials of the carrier layer and their importance for the dynamics of the gear with the tooth belt.

Vacuum System of the Module of Elements for Beam Injection into the Booster of the NICA Accelerator Complex

The design of the vacuum system of the electrostatic septum and the kicker plates (IP2) for injection into the booster of the NICA accelerator complex is developed. The components of the vacuum system are selected. The algorithm for the preparation of the vacuum chambers of the septum and kicker plates IP2 for achieving a maximum vacuum on a level of 10–11 torr is developed. Metal sealing flanges with trapezoidal teeth are proposed for the joints of the septum chamber for reliability.

A Method to Analyze the Contact Stress of Dovetail Attachments in Aeroengine

Finite element method (FEM) has been used to find out the fundamental reason of shape function due to the nonconvergence of stress in calculating the trapezoidal tooth dovetail attachments of aeroengine. We have used two different methods, representing actual models, for the calculation of contact stress. Comparative analysis of these methods, and the already reported ones, led us to conclude that the displacement extraction method is better and efficient for the engineering applications. This method was successively applied to contact model of indenter with shaped edge, a model with an inclined contact surface and dovetail attachment model, while these stress results are compared with that of photoelastic. Moreover, we found that the photoelastic and displacement error in extraction method is small and the method can be widely used for the calculation of structural stress with sharp edge.

New approaches to determine age and gender in image processing techniques using multilayer perceptron neural network

As a result of some events (disasters, inheritance, disappearances etc.), age and gender determination can be vital for people. Forensic medical institutions make the determination of age by examining the structures such as teeth and bones. Procedures for forensic science are currently estimated manually according to certain morphological findings on the tooth. In this study, 1313 panoramic dental images were used automatically to estimate age. Image preprocessing is applied on these images. Trapezoidal teeth are corrected in the coordinate plane to obtain more accurate and standard results. In the study, the correction process is done with original and novel developed algorithm. Dental images are automatically and dynamically segmented and feature vectors are created by extracting their features. The generated feature vectors are dynamic and presented as inputs to the Multilayer Perceptron Neural Network. Depending on the request, the number of input count reduction process can be performed. In this study, age and gender were determined from dental x-ray images with novel and originally developed algorithm. The application is written in C # programming language. In some tooth groups, the highest classification rate of 100% and age determination with 0 error were performed. With this study, age determination in forensic science will be more accurate.

Numerical simulation of deformation behavior of aluminum alloy sheets under processing by groove pressing method

The results of theoretical estimation of capabilities of the material structure modification of 1560 aluminum alloy sheets under processing by severe plastic deformation are presented in this paper. Severe plastic deformation of flat specimens is effected by the constrained groove pressing method in original dies with trapezoidal teeth. The numerical simulation results of the sheet specimen treatment process by severe plastic deformation were used for dies designing. The stress-strain state of flat aluminum alloy specimens and the steel dies at high processing temperature, support reaction force during pressing and the degrees of plastic strain accumulation at the optimum mode of pressing were estimated. The main numerical result is the value of accumulated plastic strain in the specimen per one pressing cycle which is about 1.14. Large degrees of strain are the reasons of grain structure and material texture changes, which leads to inevitable change of its physical-mechanical properties. Increasing the number of pressing cycles leads to proportional increase of the degree of accumulated plastic strain.

Interactive design for additive manufacturing: a creative case of synchronous belt drive

As a digital and direct manufacturing technology, additive manufacturing (AM) presents a powerful and unrestrained revolution for creative design. However the breakthrough in manufacturing technology is yet to be followed by a breakthrough in design. Firstly, the state-of-the-art overview of the existing design methods for AM is presented. Furthermore, as part of a fully 3D printed robot we envisioned, this work mainly put forward a novel synchronous belt drive as an illuminating case with the potential and constraints of AM. After capturing the flexibility based on shape innovation, a new type of continuous trapezoidal tooth belt transmission without matrix was designed. Next, using the nonlinear finite elements method, the effect laws of belt’s parameters such as tooth height, tooth width, wedge angle and belt thickness were studied on the carrying capacity of belt transmission with pre-tensioning. Moreover, a new type of synchronous belt and timing pulleys were made via the 3D printing process of fused deposition modeling with the flexible polylactic acid (PLA) material. Lastly, a driving test was carried out and the experimental results showed that the presented 3D printed trapezoidal tooth belt transmission was stable, and could meet the requirements of low speed, small power transmission, especially apt to digital design and customization. This work completely demonstrates the intrinsic nature of digital design, interactive design and custom design from/with/for AM, as well as the ever-expanding room for innovation.

Performance evaluation of trapezoidal teeth labyrinth seal

The present paper investigates the effects of the trapezoidal teeth labyrinth seal on the leakage amount in gas turbines. The influences of increasing the number of teeth from 1 to 6 with step 1 and the tip clearance s=0.5 to 7.5 mm on the leakage flow at different pressure ratios of PR=1.5, 2 and 2.5 are examined, comprehensively. The analysis is performed numerically using a Finite-Volume software with the k-e turbulent model. The obtained results show a good agreement in comparison with the other research results. The results show that an increase in the number of teeth causes a decrease in the leakage flow. An increase in the tip clearance (s) from 0.5 mm to around 7.5 mm leads to a decrease in the leakage flow, like the step labyrinth behavior, while an increase beyond 7.5 mm results into a leakage increase, the behavior of the straight labyrinth.

The quadratically cubic Burgers equation: an exactly solvable nonlinear model for shocks, pulses and periodic waves

A modified equation of Burgers type with a quadratically cubic (QC) nonlinear term was recently pointed out as a new exactly solvable model of mathematical physics. However, its derivation, analytical solution, computer modeling, as well as its physical applications and analysis of corresponding nonlinear wave phenomena have not been published up to now. The physical meaning and generality of this QC nonlinearity are illustrated here by several examples and experimental results. The QC equation can be linearized and it describes the experimentally observed phenomena. Some of its exact solutions are given. It is shown that in a QC medium not only shocks of compression can be stable, but shocks of rarefaction as well. The formation of stationary waves with finite width of shock front resulting from the competition between nonlinearity and dissipation is traced. Single-pulse propagation is studied by computer modeling. The nonlinear evolutions of N- and S-waves in a dissipative QC medium are described, and the transformation of a harmonic wave to a sawtooth-shaped wave with periodically recurring trapezoidal teeth is analyzed.