Slider-crank Mechanism Research Articles

On a pseudo-periodicity in the elastodynamics

The periodic laws of motion of a real mechanism imply the periodicity of all dynamic characteristics of the mechanism during such a movement, including the elastic displacements of its constituent links. This statement covers the most difficult problem of the dynamics of an elastically deformable body. However the existing publications devoted to the study of flexible mechanisms do not mention the periodicity of elastic displacements of the links when the mechanisms move according to periodic laws. This article discusses the periodicity and pseudo-periodicity of the elastic displacements of the links using examples of calculations of the motion of a double pendulum and a slider–crank mechanism without taking into account dissipative forces.

Design and Motion Simulation Analysis of a Novel 2D Bionic Flutter Aircraft

In order to improve the symmetry of the flutter mechanism in the bionic flutter aircraft, and then improve the overall motion stability of the flutter aircraft. In this paper, an innovative flutter wing configuration is designed based on a planar crank-slider mechanism and a sparrow model. The geometric relationship of the flutter mechanism is established, the motion of the flutter aircraft is modeled, and the dimensions of the model are optimized. The geometric relationship of the flutter structure was simulated and analyzed by CATIA. The results show that the upper limit angle of the designed flutter structure is βmax=25.82° and the lower limit angle is βmin=6.34°. The CATIA simulation data are consistent with the theoretical values of the established structural geometry model. Meeting the needs of small and medium-sized flutter aircraft.The design provides a theoretical basis for the design and development of the bionic flutter vehicle and the fabrication of a solid prototype.

Energy Dissipation Analysis for Elastoplastic Contact and Dynamic Dashpot Models

• According to the energy conservation during impact and linearized elastoplastic contact stiffness , a new hysteresis damping factor is proposed. • Anoveldynamicdashpot model ispresentedusing the elastoplasticstiffness combined with the newhysteresis damping factor. • The energy dissipationduring impactfrom the new dynamicdashpot model is fully equivalent to the one obtained from the Ma-Liumodel. • The effectivenessof the proposeddashpot model is verifiedby the experimental datafrom a granular chainand the slider-crank mechanism with clearance. This investigation aims to analyze the underlying relationship between the dynamic dashpot and the static force-displacement models used in multibody systems. By ignoring the plastic flow of the contact body made of elastoplastic material, the coefficient of restitution of the dynamic dashpot model can be calculated by using the static force-displacement model proposed by Ma and Liu (Ma-Liu model). Simulation results show the consistency of energy dissipation between the Ma-Liu model and Flores et al. model, but there are still slight differences. This is because the Hertz contact stiffness of the dynamic dashpot model overestimates the actual contact stiffness in the elastoplastic phase. Therefore, in order to eliminate this discrepancy when depicting energy dissipation during impact, the Hertz contact stiffness can be replaced by the linearized elastoplastic contact one from the Ma-Liu model; subsequently, a new hysteresis damping factor is derived based on the linearized elastoplastic contact stiffness and energy conservation during impact. Finally, a new elastoplastic dashpot model can be obtained by the elastoplastic contact stiffness combined with a new hysteresis damping factor. To verify the practicability and effectiveness of the new model, a granular chain and a slider-crank mechanism with a clearance joint are employed as numerical examples.

Rigid-Flexible Coupling Dynamics Modeling of Spatial Crank-Slider Mechanism Based on Absolute Node Coordinate Formulation

In order to study the influence of compliance parts on spatial multibody systems, a rigid-flexible coupling dynamic equation of a spatial crank-slider mechanism is established based on the finite element method. Specifically, absolute node coordinate formulation (ANCF) is used to formulate a three-dimensional, two-node flexible cable element. The rigid-flexible coupling dynamic equation of the mechanism is derived by the Lagrange multiplier method and solved by the generalized α method and Newton–Raphson iteration method combined. Comparison of the kinematics and dynamics response between rigid-flexible coupling system and pure rigid system implies that the flexible part causes a certain degree of nonlinearity and reduces the reaction forces of joints. The elastic modulus of the flexible part is also important to the dynamics of the rigid-flexible multibody system. With smaller elastic modulus, the motion accuracy and reaction forces become lower.

Modeling and simulation for wear prediction in planar mechanical systems with multiple clearance joints

The main goal of this work is to develop a comprehensive methodology for predicting wear in planar mechanical systems with multiple clearance joints and investigating the interaction between the joint clearance, driving condition, and wear. In the process, an effective contact surface discretization method together with the Lagrangian method are used to establish the dynamic equation of the multibody system. Considering the change of the contact surface, an improved nonlinear contact force model suitable for the complicated contact conditions is utilized to evaluate the intrajoint forces, and the friction effects between the interconnecting bodies are discussed using the LuGre model. Next, the contact forces developed are integrated into the Archard model to compute the wear depth caused by the relative sliding and the geometry of the bearing is updated. Then, a crank slider mechanism with multiple clearance joints is employed to perform numerical simulations in order to demonstrate the efficiency of the dynamic procedures adopted throughout this work. The correctness of the proposed method is verified by comparing with other literature and simulation results. The results show that the wear is sensitive to different initial conditions, and the evolving contact boundary makes the dynamics of mechanical system and the joint wear prediction more complex. This study is helpful for predicting joint wear of mechanical systems with clearance and optimizing the mechanism’s design.

Dynamic Modelling and Calculation of Crank Slider Mechanism of Multiparameter Friction Model in Wireless Communication

In this research work, an advanced wireless communication-based crank slider mechanism for multiparameter friction techniques is analyzed. The earlier models are unable to find exact friction; therefore, a correct crank function cannot be identified. The dynamic crank sliding mechanism is required for advanced mechanical applications. The available models are not suitable for future mechanical exhibiting. In this work, an SVM-based crank slider with a dynamic friction model is implemented. The SVM mathematical technique continually balances dynamic modeling with friction balancing. Finally, the controller/observer methods showed effective numerical outcomes. The variables of the system are analyzed, noting the mistakes and the estimations that are made. The performance measures accuracy of 98.45%, sensitivity of 97.34%, crank slider of 96.34%, and recall at 97.34%.

Design of Versatile Cassava Shredding Machine for Food Processing Industries

Manual processing of cassava tubers into its derivatives like tapioca, starch is tedious and time-consuming; this drudgery has led to this study. The purpose of this study is to enhance agricultural performance via the design and fabrication of an improved cassava shredding machine that is capable of producing different sizes of cassava slices for further processing. The essence is to reduce processing time through increased surface area. This design produces different sizes for tapioca, ijapu, abacha, lafu and for other uses. The sizes range from 8-20mm in diameter. The machine consists essentially of a hopper where peeled cassava roots are put, beneath the hopper is the shredding plate with varied cutting blades coupled to a horizontal shaft which when in operation undergoes reciprocating motion. The horizontal shaft derives its motion through a slider crank mechanism coupled to an electric motor via a belt drive with a pulley for primary speed reduction and regulation. A rugged framework is provided for mounting of the machine and electric motor. The capacity of the machine is 320kg/hr. Maximum shredding efficiency of 82% was obtained with a shred aperture ranging from 5-12mm at a shredding speed of 1200rpm.

Design and static analysis of new deployable mechanisms based on the four-bar slider–crank mechanism

This paper presents two types of new deployable mechanisms based on the motion characteristics of the four-bar slider–crank mechanism (FBSCM): the prism mechanism with constant cross-section and the round deployable mechanism. A new basic planar deployable unit based on the path-generating characteristics of the FBSCM is proposed. The method of building a deployable mast unit with one DOF from the new planar deployable mechanism is given. The prism mechanism with constant cross-section of one DOF is constructed, and the magnification ratio is analyzed. Moreover, the deployable unit with a negative Poisson’s ratio for building the round deployable mechanism based on the properties of functional output of the FBSCM is proposed. The structure of the round deployable mechanism is described, and the parameter model with multilevel deployment is calculated and validated with cases given; the DOF of the round deployable mechanism is one. Last, the static analysis of the round deployable mechanism is studied by simulation; by locking 6 guide rails, the structure is found to have a balanced bearing capacity, and the bearing performance is improved compared with locking only one guide rail.

Numerical and experimental study on dynamic characteristics of planar mechanism with mixed clearances

Clearances in joints are unavoidable due to assemblage, manufacturing errors and wear, which will lead to poor dynamic performances and undesirable vibrations due to impact forces in clearance joints. In dynamics analysis of planar mechanical system, it is usually assumed that the revolute joint is planar joint with radial clearance. However, the axial clearance in the revolute joint and the clearance in the translational joint are ignored. In fact, even planar mechanical systems may exhibit out-of-plane motion due to misalignments. In this work, a planar slider-crank mechanism is used as the example to investigate the effects of mixed clearances on the dynamic responses of planar mechanical system considering radial and axial clearances in spatial revolute joint due to axis misalignment as well as clearance in planar translational joint. The dynamic responses of the planar slider-crank mechanism system with two spatial revolute clearance joints and a planar translation clearance joint are investigated using computational and experimental methodology. The mathematic model of the spatial revolute clearance joint and the planar translational clearance joint are presented. The clearance joints are considered as force constraints and the joint components of an imperfect joint with clearance are modeled as contact bodies. The normal contact force model of clearance joint is established using continuous contact force model. The friction effect is considered using modified Coulomb friction model. Different case studies are presented and discussed to investigate the effects of the mixed clearances on the dynamic responses of the planar slider-crank mechanism.

Mechanism and Kinematics for Flapping Wing Micro Air Vehicles Maneuvering Based on Bilateral Wings

With the development and application of a bionic flapping micro aircraft vehicle (FMAV), further requirements for its high maneuvering flight characteristics have been put forward. A controlling tail cannot meet the requirements of the maneuvering flight of insect-sized FMAVs, and it has become necessary to find new mechanisms for high maneuvering flight. In this study, two flapping mechanisms with movable hinges based on a double crank rocker mechanism (DCRM) and a single crank slider mechanism (SCSM) are proposed. The instantaneous flapping angles, their extremum and means, and the flapping amplitudes of the two mechanisms are studied for various hinge offsets. A comparison between these two mechanisms indicates that the mechanism based on SCSM is more appropriate in providing adjustable flapping amplitudes for lateral wings. Finally, a dragonfly-like prototype assembled using a carbon fiber plate with adjustable wings is designed and manufactured based on the SCSM. Flight tests are conducted to show that the rack and pinion mechanism can accomplish the movement of hinges neatly, and the proposed flapping mechanism makes left turns and right turns effectively while continuing to fly forward. The prototype is good in terms of crashworthiness and the replacement of components, and it offers an easy and reliable technique for the maneuvering flight of FMAVs.

Design, Manufacturing and Testing of a Stirling Engine with Slider-Crank Mechanism

In this study, a beta type Stirling engine with slider-crank mechanism having swept volume of 365 cm3 was designed, manufactured and performances tested. The design phase was first started by determining the operating parameters of the engine. The necessary mathematical calculations were performed by considering the operating conditions of the Stirling engine with a slider-crank mechanism to be manufactured. After determining the engine parameters, the dimensional design phase was started within the tolerance limits of the engine parts. The parts were designed by the computer-aided SolidWorks program in solid modeling and by the AutoCAD program in two-dimensional design and projecting. Each part used in the manufacturing of the Stirling engine was assembled delicately in the assembly process. A prony-type dynamometer, liquefied petroleum gas (LPG) fuel, and electronically controlled electric heater systems were developed to perform the performance tests and analyses of the manufactured engine. Experimental studies were conducted at hot end temperatures of 627 °C, 727 °C, and 827 °C and at a cold end temperature of 27 °C by utilizing an electrical heater as a heat source and air as a working fluid. According to the results obtained in experimental studies for different heater temperatures and different charge pressures, it was revealed that engine power values increased depending on the heater temperature and charge pressure increase. The maximum power values at all heater temperatures were acquired at a charge pressure of 4 bar. In this study, the maximum engine power was obtained as 69.5 W at a hot end temperature of 827 °C, at a charge pressure of 4 bar, and at an engine speed of 200 rpm when a stainless-steel displacement piston and air as a working fluid were utilized, and the maximum engine torque value was obtained as 4.21 Nm at a charge pressure of 4 bar and an engine speed of 135 rpm. The lowest engine power among the maximum engine power values obtained in all experimental studies was found as 17.09 W at a hot end temperature of 627 °C, at a pressure of 1 bar, and at an engine speed of 185 rpm. The maximum power values of the engine developed within the scope of this study at hot end temperatures of 627 °C, 727 °C, and 827 °C were determined to be 31.2 W, 48.3 W, and 69.5 W, respectively. Upon examining the results obtained from experimental studies, it is observed that the heater temperature and charge pressure have significant impacts on the performance values of Stirling engines. Within the scope of this study, a new power generation system that could use renewable energy sources was put into operation.

Characterization of Magnetorheological Fluid: A Study on Sedimentation and Redispersion

Herein, an induction method based setup for quantification of sedimentation behavior of magnetorheological fluids (MR fluids) consisting of 10% carbonyl iron powder in silicone oil is used. The effect of addition of Aerosil (stabilizer) on sedimentation is proposed with the help of “sedimentation index.” The proposed model of sedimentation index is compared with experimental measurement and is found to be in good agreement. In case of unavoidable event of settling, the important point is the ease of redispersion of sediment. This is directly evaluated with the help of a slider crank mechanism based setup which is proposed on the basis of the actual application. The quantification of redispersibility of the settled MR fluid is proposed using novel “redispersion index.” It is observed that increasing the concentration of Aerosil reduces the settling due to high off‐state viscosity, however, at the cost of redispersibility. In this study, the optimum trade‐off between the redispersibility and slow settling is obtained with 15% concentration of Aerosil in the MR fluid.

Design, analysis and evaluation of a self-lockable constant-force compliant gripper

Maintaining a constant gripping force is a challenging problem when manipulating fragile objects with variations of sizes and stiffness. In this paper we develop a novel constant-force compliant gripper with clamp state locking capability, which is composed of the constant force module, the multi-stable module, the adjustment module and the actuator module. In particular, the symmetric compliant slider-crank mechanism is employed to maintain a constant force between the jaw and object. The multi-stable module with behaviors of snap-through and negative stiffness is designed to balance the interaction force from the constant force mechanism (CFM). With this, the gripping state, including the gripping force and the jaw position, can be locked during the gripping operations. Theoretical model of the constant-force compliant gripper is also established, where the force-displacement relationships is analyzed and verified by finite-element simulations. Experimental studies on an additive manufactured prototype are further conducted, which effectively validates the constant gripping force and force self-locking performance of the developed gripper.

Make the mechanical model for rotational-to-linear motion transformer using a double eccentric crank

A mechanism converting straight to cycle motion, for example a slider-crank mechanism is used for internal combustion engine. The research group suggested the Rotational-to-Linear motion Transformer using a Double eccentric Crank (RLTDC) as new mechanism convert straight to cycle motion. This mechanism is developed based on Oldham coupling (double-slider mechanism) and slider-crank mechanism, which can be expect for size down machines using a mechanism convert straight to cycle motion because stroke is double comparing a slider-crank mechanism on equal crank length. But, from the experimental measured value of the kinetic load in the preceding study, the matter that the durability of a slider guide would be concerned is revealed. So，the relationship between the peak value of load acting on the slider guide and the slider position is needed to be clarified. In this study, the process making the mechanical model for this relationship is shown.

Design and analysis of compact paddy harvester machine

Modern technologies were developed in agricultural industry with vast range of equipment for efficient farming and harvesting process. In meanwhile, the challenging issue is that it is not affordable to the farmers with poor economic background and small-scale farmers who might frequently face the problem of labour shortage. The purpose of this work is to develop a new agricultural machine that fit to various conditions in the agricultural field for harvesting. The machine comprises of a petrol engine of 2 HP (Horsepower), collecting unit, pulley, belt drive, and cutter blades. The crop cutting is being done by a scissoring type of motion where the blade cuts the mature crop and transmit in horizontal position through belt conveyer and then the crop is collected in the collecting tank having a capacity of 0.25 ton. The slider crank mechanism is used to transmit the power to the cutter which is driven by pulley. A collecting unit is provided to collect the harvested crop. The proposed machine shows improved efficiency when compared to traditional and modern methods.

Slider-crank mechanism in a molecular crystal: conversion of linear thermal expansion of a lattice to circular rotation of a coordination chain

Slider-crank like force conversion of linear thermal expansion to rotational motion of the coordination chains were observed in the molecular crystal.

Кинематический синтез безмуфтового механического пресса на основе рычажного механизма третьего класса

The article discusses the kinematic scheme of the lever crank-slider mechanism of the third class, on the basis of which the executive mechanism of a mechanical non-clutch press is proposed under the patent for the invention (RF patent No. 2752399). Switching mode of operation of the press is carried out by moving the control slider from one stationary position to another. The kinematic parameters of the lever mechanism are assigned in such a way that in operating mode the law of motion of the working body of the press is close to the law of motion of the output link of the fourlink central crank-slider mechanism, and in the idle mode — the working body makes small movements (approximate stand) at full rotation of the crank. The analytical dependencies necessary for calculating the mechanism and the corresponding example are given.

Kinematic reliability evaluation of high-precision planar mechanisms experiencing non-uniform wear in revolute joints

Joint clearance significantly influences the motion accuracy of a mechanism. Most of the existing studies assumed that the clearance is regular with constant size. The effect of irregular joint clearance due to wear on the kinematic accuracy is ignored. Hence, this study conducts kinematic reliability analysis of high-precision planar mechanisms experiencing non-uniform wear. Firstly, under the framework of multi-body dynamics, an efficient wear prediction method based on Archard’s wear model is presented for parameterized description of the clearance boundary. Secondly, fractional moments of the motion output considering the uncertainties of driving actuators, link dimensions and non-uniform joint clearance are derived with the dimension reduction method. On this basis, the maximum entropy model constrained by fractional moments is employed to approximate the distribution of the motion output. Then the kinematic reliability is accordingly calculated using the numerical integral. Meanwhile, a Monte Carlo simulation (MCS) based method is developed for kinematic reliability analysis by virtue of slicing sampling technique to provide a reference solution. Finally, experimental testing of a slider-crank mechanism is presented to verify the wear prediction method. The slider-crank mechanism is also used to demonstrate the effectiveness of the proposed kinematic reliability evaluation method.

A regularization method for solving dynamic problems with singular configuration

In the simulation process for multi-body systems, the generated redundant constraints will result in ill-conditioned dynamic equations, which are not good for stable simulations when the system motion proceeds near a singular configuration. In order to overcome the singularity problems, the paper presents a regularization method with an explicit expression based on Gauss principle, which does not need to eliminate the constraint violation after each iteration step compared with the traditional methods. Then the effectiveness and stability are demonstrated through two numerical examples, a slider-crank mechanism and a planar four-bar linkage. Simulation results obtained with the proposed method are analyzed and compared with augmented Lagrangian formulation and the null space formulation in terms of constraints violation, drift mechanical energy and computational efficiency, which shows that the proposed method is suitable to perform efficient and stable dynamic simulations for multi-body systems with singular configurations.

Experimental Investigation of the Dynamics of a Slider-Crank Mechanism With Local Linear Force Input

Abstract Conventional implementation of slider-crank mechanisms result in high loads transmitted through the mechanical structure, inhibiting the design of compact and oil-free machines. Therefore, this research proposes to step away from the conventional, i.e., rotative, actuation and to investigate local linear actuation on the slider-component directly, while maintaining the kinematic link of the slider-crank configuration. In this work, the local linear actuating principle is evaluated experimentally where the goal is to obtain a continuous movement of the slider mechanism where Top Dead Center & Bottom Dead Center are reached and to minimize the loads transmitted through the mechanical structure. The non-isochronous transient behavior of a slider-crank mechanism loaded with a spring-damper element is detailed as well as the optimal working conditions at steady-state to achieve a reduced loading of the kinematic structure. By matching the operating frequency and resonance frequency of the system, a reduction of the loads transmitted through the system by 63% of the nominal spring load can be achieved. Further experimental (and multibody mechanical) investigation on the influence of flywheel exposes a clear trade-off between the sensitivity of the system and the transmission of the actuation force through the kinematic link.