Spiral Spring Research Articles

A General Modeling Methodology for the Quasistatic Behavior of Spiral Torsion Springs

Abstract Due to their robustness, compactness, simplicity, and the possibility of nonlinear torque curves, spiral springs are being increasingly contemplated for industrial application. Recent manufacturing technologies and materials allow for the creation of spiral springs of various shapes and geometries able to provide the required torque curves. Modeling the behavior of this kind of springs is highly complex due to the strong nonlinearities arisen from large deflections and the possibility of coiling of strip length around the spring barrel or arbor. For this reason, up to our knowledge, existing models only provide design features such as deflection and torque curve for the simplest strip geometries, and fewer models supply, only if no strip coiling occurs, reactions at the strip-barrel and strip-arbor clampings. In addition, to our knowledge, just semi-empirical models for strip-barrel, -arbor and -strip contact forces or friction torques were available. In this work, we introduce a novel general, an analytical quasistatic model for the calculation of all the above spring characteristics for any length-dependent strip material and initial geometry and strip cross-sectional shape and for any barrel and arbor radii. The strip deflection curvatures are calculated minimizing the sum of elastic and gravitational potential energies under geometrical constraints associated with eventual strip coiling. Once the curvatures are calculated, the spring internal, contact, and reaction forces can be straightforwardly calculated by solving the elastica differential equations. Friction is taken into account by evaluating the contact conditions at the strip coiled sections.

Integrated Shock Absorber With Both Tunable Inertance and Damping

Inerter is a two-terminal mass element and the applied force is proportional to the relative acceleration between the terminals. According to the second class of mechanical-electrical analogy, the inerter corresponds exactly to the capacitor in the electric network. Aiming at improving the limited vibration isolation performance using constant inertance of conventional inerter, a new semi-active inerter based on smart material, magnetorheological (MR) fluid, is proposed in this paper. Further, according to the design concept of “functional integration”, the MR inerter, an MR damper and a spiral spring are integrated to realize a new integrated inerter-spring-damper (IISD) with both adjustable inertance and damping characteristics. The MR inerter consists of a ball screw, an MR clutch, MR fluid, excitation coils, an excitation shell, a flywheel, a flywheel shell, a connector, upper and lower covers, bearings and seals. The tunable inertance is achieved by adjusting the excitation current in the excitation coils to change the operating state of the MR clutch. The MR damper and the spiral spring provide variable damping and constant stiffness, respectively. The mathematical model of the IISD is established. The adjustment principle of inertance is verified by numerical simulation, and the mechanical output characteristics of the IISD are analyzed. Besides, the 1/4 vehicle suspension model based on the proposed IISD is built by using MATLAB/SimMechanics. The frequency response and unit impulse response characteristics of the suspension are obtained via the comfort-oriented virtual experiment. The simulation results show that the suspension with the IISD has a 23.0% higher performance than the conventional suspension in vehicle body acceleration, and the suspension deflection and dynamic tire load are also improved.

Improvement of heat transfer in heat exchangers with spiral springs with the square cross-section area

The purpose of this study is to investigate the effect of spiral springs with the square cross-section area on heat transfer and pressure drop in heat exchangers. The springs were fitted inside a circular cross-section copper tube. The diameter and length of the copper tube were 25.4 mm and 1820 mm, respectively. The experiments were performed with 9 spiral springs of 12 and 15 mm diameter in four pitches of 2, 5,10,20 mm and 21 mm diameter in three pitches 10, 20 and 30. The fluid used in all experiments was water and the Reynolds number for the hot water flow into the copper tube was in the range of 22,462 to 36,456. Cold water was used to cool around the copper tube and rate of cold water flow was also 0.1547 kg / s. The heat transfer coefficient increased by 45% after the springs were placed inside the copper tube in comparison to the no-spring condition. However, the pressure drop in the worst case increased by 77%. It can also be seen that the heat transfer coefficient increased to 20% by increasing the diameter of the springs by 75%. Meanwhile, the springs with a diameter of 21 mm and 12 mm has the most and the least effect on increasing the heat transfer coefficient, respectively.

Lasheen technique for lengthening of spermatic cord in management cryptorchidism (Lasheen spiral spring)

Background: Undescended testis is the most common anomaly of male genitalia. In these cases the testis lies at any position other than the normal scrotal position. The goal of surgery is to move the testis to scrotum, but short spermatic cord represent the big problem. Our study offers new technique for lengthening spermatic cord depends on tissue expansion theory.

Adaptive speed control of PMSM for energy storage process of MEES

Mechanical elastic energy storage (MEES) system completes the energy storage process through permanent magnet synchronous motor (PMSM) rotates and tightens the energy storage boxes which contains large spiral torsion springs (STSs) to convert electrical energy into elastic potential energy. The torque of the storage box is gradually increased while the moment of inertia is gradually reduced in the process of energy storage. Thus, this paper proposed an backstepping control scheme with torque and inertia adaptive law and the stability was proved in the sense of Lyapunov theory. The effectiveness of the proposed scheme was verified through hardware experiments. The results indicated that the proposed scheme ensures the speed to track the given value rapidly and the energy storage process can be carried out smoothly.

Multimodal Hybrid Piezoelectric-Electromagnetic Insole Energy Harvester Using PVDF Generators

Harvesting biomechanical energy is a viable solution to sustainably powering wearable electronics for continuous health monitoring, remote sensing, and motion tracking. A hybrid insole energy harvester (HIEH), capable of harvesting energy from low-frequency walking step motion, to supply power to wearable sensors, has been reported in this paper. The multimodal and multi-degrees-of-freedom low frequency walking energy harvester has a lightweight of 33.2 g and occupies a small volume of 44.1 cm3. Experimentally, the HIEH exhibits six resonant frequencies, corresponding to the resonances of the intermediate square spiral planar spring at 9.7, 41 Hz, 50 Hz, and 55 Hz, the Polyvinylidene fluoride (PVDF) beam-I at 16.5 Hz and PVDF beam-II at 25 Hz. The upper and lower electromagnetic (EM) generators are capable of delivering peak powers of 58 µW and 51 µW under 0.6 g, by EM induction at 9.7 Hz, across optimum load resistances of 13.5 Ω and 16.5 Ω, respectively. Moreover, PVDF-I and PVDF-II generate root mean square (RMS) voltages of 3.34 V and 3.83 V across 9 MΩ load resistance, under 0.6 g base acceleration. As compared to individual harvesting units, the hybrid harvester performed much better, generated about 7 V open-circuit voltage and charged a 100 µF capacitor up to 2.9 V using a hand movement for about eight minutes, which is 30% more voltage than the standalone piezoelectric unit in the same amount of time. The designed HIEH can be a potential mobile source to sustainably power wearable electronics and wireless body sensors.

Travel switch integrated mechanical regulation triboelectric nanogenerator with linear–rotational motion transformation mechanism

Triboelectric nanogenerators (TENGs) are being widely studied as a new way to harvest environmental energy. TENGs can reliably provide energy for low-power sensors, which are widely used in industry and modern life. Aiming to convert external random vibration energy into controllable electrical energy, this paper presented a travel switch integrated mechanical regulation triboelectric nanogenerator (TSMR–TENG) with linear–rotational motion transformation mechanism. The TSMR–TENG consisted of a shell, linear–rotational motion transformation mechanism, inertia wheel, and travel switch. This structure possessed the advantages of small size, easy integration, and high reliability. In the device, the linear–rotational motion transformation mechanism converted linear random vibrations into rotation, and then the energy of rotation was stored in a spiral spring. When enough energy accumulated, the travel switch turned on, and then the spiral spring caused the inertia wheel to rotate. The triboelectric materials on the inertia wheel slid against a copper electrode, which converted the stored energy into electricity. The TSMR–TENG achieved controllable electrical energy output under random vibration excitation. The open–circuit voltage of the TSMR–TENG was about 400 V and its short-circuit current was 17 μA. The TSMR–TENG lit up 500 light-emitting diodes in a single operation and drove commercial thermometers through rectifier bridges and capacitors. This work provides a new type of TENG that can generate electricity steadily in the natural environment.

Mechanisms of negative membrane curvature sensing and generation by ESCRT III subunit Snf7.

Certain proteins have the propensity to bind to negatively curved membranes and generate negative membrane curvature. The mechanism of action of these proteins is much less studied and understood than those that sense and generate positive curvature. In this work, we use implicit membrane modeling to explore the mechanism of an important negative curvature sensing and generating protein: the main ESCRT III subunit Snf7. We find that Snf7 monomers alone can sense negative curvature and that curvature sensitivity increases for dimers and trimers. We have observed spontaneous bending of Snf7 oligomers into circular structures with preferred radius of ~20 nm. The preferred curvature of Snf7 filaments is further confirmed by the simulations of preformed spirals on a cylindrical membrane surface. Snf7 filaments cannot bind with the same interface to flat and curved membranes. We find that even when a filament has the preferred radius, it is always less stable on the flat membrane surface than on the interior cylindrical membrane surface. This provides an additional energy for membrane bending which has not been considered in the spiral spring model. Furthermore, the rings on the cylindrical spirals are bridged together by helix 4 and hence are extra stabilized compared to the spirals on the flat membrane surface.

An integrated scheme of speed control and vibration suppression for spiral spring energy storage system driven by PMSM based on backstepping control with minimum electrical loss

The operational performance of the spiral spring energy storage system is affected by the vibration of the spiral spring and the electrical loss of the permanent magnet synchronous motor. It is important to eliminate vibration and reduce electrical loss. A unified control scenario for speed regulation and vibration suppression based on the minimum electrical loss is proposed. First, the spiral spring is equivalent to an Euler–Bernoulli beam and its dynamic model suitable for control is established via the Lagrange equation. Then, the unified control scenario is proposed through nonlinear backstepping control. The speed controller and current controller including modal vibration suppression and minimum electrical loss operation of the system are established, and the stability of the controller is theoretically proved. Moreover, for unknown vibration mode of the spiral spring, a vibration mode–based estimation method with the least-squares algorithm is designed. Aiming at the uncertainty of the permanent magnet synchronous motor’s iron loss resistance, an estimation algorithm based on an adaptive neural fuzzy inference system is designed. The experimental results verify the correctness and effectiveness of the proposed control scheme. In comparison with traditional backstepping control, the proposed control method can effectively suppress the vibration of the spiral spring and realize the stable and highly efficient energy storage operation of the system.

Design, development and modelling of single actuated, compliant and symmetrical multi link hopping mechanism

In this study, we present the design and development of a compliant multi-link hopping mechanism actuated by a single DC motor. Mechanism consists of torsional spring, two symmetrically arranged six bar mechanism connected through the bottom gears and a compliant preloaded pinned-pinned buckling beam serving as a nonlinear spring. Kinematic and dynamical analysis are performed using both Newtonian dynamics, vector closure loop equations and geometric constrains of the design to predict the motion of the mechanism. Adams simulations are performed to obtain the force-deflection curve for flexible beam and torque-angular displacement curve for flat spiral spring. Mechanism is built by 3D printing all parts using thermoplastic based polylactic acid PLA filament. Continuous hopping motion is created without requirement of any hydraulic and pneumatic actuators or mechanical springs to store and release energy during the complete motion. The actuator is connected to a 3D printed flat spiral spring to control the speed and pinned-pinned buckling beam is attached in between two symmetrical multi-link mechanism to increase the effect of impact.

Human postural ankle torque control model during standing posture with a series elastic muscle-tendon actuator

The main motivation behind the creation of a compliant actuation system is to provide safety, capability of storing energy, and improved performance levels in dynamic behavior of the mechanical human ankle. In this paper, a torsional flat spring (TFS) is proposed to provide high compliance and deformation values for human ankle series elastic muscle-tendon actuator system (HA-SEMTAS). The proposed torsional flat spring uses two torsional flat spiral spring in opposite directions, as the torsional flat spiral spring generates torque only in one direction. First, we present the characteristics of the TFS for an ankle joint, and the design and modeling of the HA-SEMTAS are developed. Modelling of the HA-SEMTAS simulates the responses of fluctuations in the center of mass and center of pressure and offers the possibility of measuring sensor activation, decomposition of reactive torque and participation of each set of muscle groups to balance posture. In order to control ankle angles and torque of Human system, torque controllers (PID and PD-feedforward) are generated for (HA-SEMTAS). The controller inputs are torsional flat spring position errors and error rates. Feedforward and integral action were applied to reduce the steady-state error of the system. It is seen that PID + ff of the system developed here is robust to step and ramp-type disturbances. Real-time controllers are embedded in GoogolTech GT-800 Industrial PC. Experimental results confirm that the step tracking of human upright posture behavior is satisfactory and overall system stability has improved using the proposed controller and compliant actuation system. It is also shown that PD + feedforward yields better performance than PID controller.

МОДЕРНИЗАЦИЯ ХОДОВЫХ ЧАСТЕЙ ТЕПЛОВОЗА ТЭ109

In the design of modern diesel locomotives equipped with three-axial bogies both in our country and abroad there is widely used a spring hanger made as cylindrical spiral springs of compression with the use of hydraulic shock absorbers. At that the boxes of wheel pairs are connected with frames with the aid of carriers. 
 A considerable drawback of such bogies is that these designs do not allow obtaining the angular turn of wheel pairs during their motion along curvilinear areas of a railway. That is why in practice an increased wear of wheel flanges of wheel pairs takes place. In Bunin SU of Yelets at the level of the invention (RU2604924) there is developed a promising design of a spring hanger excluding such a drawback and a series of computations for substantiation of its efficient design parameters. The investigation results are recommended by research and industrial companies in the field of heavy engineering both in our country, and abroad with the purpose of the further study of the design developed and its possible introduction in practice.

Analysis, Design, and Preliminary Evaluation of a Parallel Elastic Actuator for Power-Efficient Walking Assistance

This paper introduces the analysis, design and preliminary evaluation of a self-integrated parallel elastic actuator (PEA) with an electric motor and a flat spiral spring in parallel to drive the hip joint of lower limb exoskeletons for power-efficient walking assistance. Firstly, we quantitatively analyze the reason why the parallel elasticity (PE) placed at the sagittal hip joint can reduce the motor power requirement during walking assistance, which contributes to the theory of PEA development and application. The design of the PEA is then introduced in detail. The novelty of the design is that the actuator is reduced in size by integrating the spring into the motor, and the requirement of spring stiffness is significantly reduced by placing the spring directly parallel to the motor shaft. Furthermore, both the simulation based on dynamic modeling and benchtop experiment are conducted preliminarily to evaluate the performance of the PEA with nine spring stiffnesses in a range from 0 – 5.29 mN $\cdot \text{m}$ /rad regarding two indexes including the average and maximum positive electrical power of the motor. Their results show that the two indexes become smaller when the PE is attached and decrease as the spring stiffness increases. When the PE with a stiffness of 5.29 mN $\cdot \text{m}$ /rad is attached, the actuator obtains the largest reduction rate of 11.99 and 16.84 % in the average (root mean square) and maximum positive electrical power of the motor in the simulation and 10.3 and 26.25 % in the experiment, respectively. Those results provide evidence for the applicability of the newly designed PEA in driving a lower limb exoskeleton with high power efficiency during walking assistance for paraplegic patients with complete loss in walking ability.

Mechanical behaviors of radial symmetric pyramid kirigami

Kirigami, the art of cutting paper, recently emerged as a powerful tool to substantially modify, reconfigure and program the properties of material. The development of kirigami technology provides an effective solution for designing the inorganic flexible electronic devices. Pyramid kirigami, as a kind of kirigami structure, shows a large vertical extension characteristic. It has been widely used to demonstrate versatile applications, such as graphene kirigami spiral spring, three-dimensional stretchable supercapacitor, and wearable flexible sensors. In the present work, we construct a polygonal radial symmetric pyramid kirigami by introducing some cuts in the elastic sheet. The mechanical behavior of pyramid kirigami is investigated based on the cantilever formula solved by Galerkin method. In addition, a “beam model” is proposed to explain deformation process of pyramid kirigami, which consists of several “beam elements” containing two cantilever beams. The formula for the relationship between the elastic coefficient <i>K</i> and the structural parameters of the regular <i>N</i>-sided pyramid kirigami of <i>n</i> modules is obtained by combining several cantilever beams. The formula for the linear threshold of deformation <i>D</i><sub>T</sub> is obtained based on the comparison between the approximate curve of small deflection and the theoretical curve of a cantilever beam. When the deformation of the structure exceeds the linear threshold, the structure cannot keep the elastic coefficient <i>K</i> value linear any more, and the mechanical behaviors become non-linear. The simple geometric relationship of a single module is used to explain the out-of-sheet distortion of the structure. The proposed theoretical model is confirmed by finite element method simulation and experimental methods, and it is used to analyze the mechanical characteristics of graphene krigami reported. The results indicate that the defined parameters can be adjusted to tailor or manipulate the ductility and mechanical behaviors. This work provides theoretical support for the application of pyramid kirigami in the field of flexible devices. In the macroscopic field, the pyramid kirigami structure is expected to be applied to the field of flexible devices as a flexible structure with controllable elastic coefficient. In the microscopic field, it is expected to use two-dimensional materials to make force measurement devices with a simple visual readout and femtonewton force resolution.

Metal Cylindrical Sieve (MCS) for plasma confinement and low sputtering nitrogen plasma immersion ion implantation

Nitrogen Plasma Immersion Ion Implantation (N-PIII) was performed in the Metal Cylindrical Sieve (MCS) configuration that consists of Stainless Steel 308 L (SS308L) spiral spring wound wire. Two N-PIII regimes were obtained: one using a current of 5 A (with ends open), in which an intense sputtering of the wire occurs while for currents above 12 A (with one side closed), the sputtering is diminished substantially. This behavior at different powers in MCS can be explained in terms of the sheath overlapping between the spiral spring paths. The plasma density near the wire is insufficient to overcome the sheath overlapping between the spiral spring paths when the current is low, which leads to high sputtering of the wire surface. However, in high current, sheath overlapping is avoided and high ion implantation condition is achieved. FEG-SEM analyses of the silicon sample placed on the screen plate in front of MCS mouth indicated a high deposition of the sputtered material at low current in contrast with low deposition at high current. These deposition free results allow us to plan efficient N-PIII treatments of different types and sizes of metal springs, grids, rings, and wires, with high performance, for industrial and scientific applications.

THE USE OF ALTERNATIVE METHODS OF EDUCATIONAL-LABORATORY RESEARCHES IN THE GENERAL PHYSICS COURSE FOR ENGINEERING AND TECHNICAL SPECIALISTS TRAINING IN THE FIELD OF MECHANICS

The development of a modern methodology of physics studying for technical students on the basis of a competent approach is a complex problem and in the conditions of science-intensive production depends on the systematic and methodical feasibility of the various forms use and means of training. For effective professional activity in any field of high-tech production, it is necessary not only have a sufficient amount of fundamental knowledge and a deep understanding of the main point of nature physical processes, but most importantly, analytical creative thinking, which is formed during the process of independent study of problem physical tasks in a laboratory practice.Relying on the many years of experience in using the training-laboratory practice in the department of physics at DSTU, we consider it advisable to implement variation laboratory works containing a complex of alternative experimental studies of physical quantities appearing in various physical phenomena and laws for the effective formation of professional competencies and creative abilities of students. In this paper, an example of determining the stiffness coefficient of springs is considered, which is actual for undergraduate mechanical students. Alternative variants of laboratory methods for studying power and force characteristics of spiral springs on the examples of various physical processes of practical application have been considered. The possibilities of experimental determination of the stiffness coefficient of springs on the basis of energy conservation law, when used as a catapult, have been investigated.The laboratory method for elastic characteristics determination on the example of dying oscillations of one-dimensional spring pendulum, which takes into account both the real period of oscillations and the decreasing decrement, has been developed and clearly grounded. The method of stiffness coefficient determination in the study of rotational oscillations of a massive disk on a spring fastening has also been substantiated.

Moment of inertia analysis of rigid bodies using a smartphone magnetometer

This study reports the experimental results of the measurement and analysis of the moment of inertia (MOI) of rigid bodies using a smartphone magnetometer. The MOI apparatus comprises a spiral spring, stand, deviation scale, and vibration counter. The magnetometer application used on the smartphone is the Physics Toolbox Sensor Suite. The magnet, which is placed on top of the MOI apparatus, rotates with the rigid body, and the smartphone magnetometer is used to detect the magnetic field values. We experimentally determine the relationship between the magnetic field and time. The time function is used to analyse the oscillation period of the rigid bodies, which comprise a solid cylinder, solid sphere, solid cone, and solid circular disc. The oscillation periods are proportional to the radii of the rigid bodies. This experience will trigger student interest in conducting related experiments.

Analysis of injector spring damage to determine maintenance management diesel engine at PLTD Ampenan

The injector spring in cylinder #2 of a diesel engine in Ampenan PLTD which is operated by PT. X damaged. After visual inspection, a helical spring of the injector was broken. The spring broke in the lower part, in winding 2 of the spring. Before the damage was known, with a diesel load of 1100 kW, the exhaust manifold the cylinder #2 was glowing. Root cause analysis of the broken spiral spring was carried out by visual observation, metallography, and maintenance management analysis. Results indicated that the damaged of the broken injector spring based on visual observation of the helical spring was due to alternating bending loads. The fracture angle was at 450 indicated a bending load. Benchmark shows the beginning of the fault, followed by a static fracture. Metallographic and microstructure examination results found too many sulphides possibly making the formation of the onset of the fatigue. To minimize the damage, the sulphide amount of the spring must be reduced, and the spring injector material must be redesigned. Maintenance management must check every time the new spring is received and the cam lobe dimensions and wear of the roller must be lifted every 1000 hours.

Analytical model of ear dynamics and conditions for efficient grain extraction

The paper is devoted to studying the motion dynamics of stem and ear, as well as particular wheat grains. The purpose of this consideration is to establish parameters of the effect on the plant as a whole, and in particular on the ear, for the efficient extraction of grains from the ear. For this, a mathematical model of the interaction between the elements of the stem-ear-grain system and the conditions for the separation of grain from the ear is built. In a first approximation, a simple stem model consisting of absolutely rigid bodies interconnected by elastic bonds is taken as such a model. Stems with a given moment of inertia act as such bodies, and spiral springs act as elastic bonds.

A non-cooperative rear-end collision avoidance scheme for non-connected and heterogeneous environment

Rear end collisions are deadliest in nature and result in life losses and severe injuries. Many of the proposed rear-end collision avoidance schemes focus only on specific aspects without considering several non-direct factors, such as driver inattention or distraction, tailgating, panic stops, street surface circumstances, driver response time, person on foot stream and vehicle elements. Henceforth presenting greater challenges in proposing a precise numerical model of the vehicle control framework. Moreover, most collision avoidance schemes incorporate fuzzy logic for formulating human inspired collision avoidance controllers. But the problem with a fuzzy based controller is that their efficiency is greatly affected by the number of rules being deployed. Furthermore, no such agent-based modeling has been utilized, which can effectively model the human-inspired behavior. Literature is full of vehicle control frameworks that work in a connected and homogeneous environment, again critics have raised several questions for such frameworks working in a connected environment. This study aims not only to identify these key issues but also propose a human-inspired physics based Spiral Spring based Simple Reflex Agent for rear end collision avoidance. Our scheme will not only work in the non-connected and heterogeneous environment but will also consider the distraction causing road factors and effectively handle them. Extensive experimentations and presentation for the proof of concept have supported our claims and worthiness of proposed agent-based scheme.