Spiral Spring Research Articles

Energy Transfer of an Axially Loaded Beam With a Parallel-Coupled Nonlinear Vibration Isolator

Abstract Traditional vibration isolation of satellite instruments has an inherent limitation that low-frequency vibration suppression leads to structural instability. This paper explores a parallel-coupled quasi-zero stiffness (QZS) vibration isolator for an axially loaded beam, with the goal of enhancing the effectiveness of low-frequency isolation. A QZS contains two magnetic rings, which contribute negative stiffness, and one spiral spring, with positive stiffness, a combination that has high static stiffness to resolve the structural instability. The frequency response functions (FRFs) of power flow are used to measure the effectiveness of vibration isolation. The magnetic stiffness of the magnetic rings is calculated using the principle of equivalent magnetic charge. The heights, radii, and gap of the magnetic rings affect its stiffness. The parallel-coupled QZS vibration isolator of an axially loaded beam is modeled using an energy method. Based on the Galerkin truncation, harmonic balance analysis, and arc-length continuation, an approach is proposed to analyze the FRFs of power flow for the parallel-coupled QZS vibration isolation of an axially loaded beam. Numerical results support the analytical results. Both analytical and numerical results show that the power reduction of axially loaded beams with a parallel-coupled quasi-zero vibration isolation system is more significantly suppressed at low frequencies.

Wind power harvester based on an aerodynamic double pendulum

Dynamics of an aerodynamic double pendulum coupled with a linear generator is considered. A cubic nonlinear spiral spring is installed in the first joint of the pendulum. Numerical simulation of the behavior of the pendulum is performed. It is shown that it is possible to choose parameters in such a way as to ensure the instability of the equilibrium and the existence of limit cycle oscillations. Such oscillations are required for the system to be capable of wind power harvesting. The influence of characteristics of the joint spring upon the amplitude and frequency of the cycles is analyzed. In particular, it is shown that the amplitude non-monotonically depends on the parameter characterizing the cubic nonlinearity of the stiffness. In the same time, frequency monotonically increases as this parameter increases. The influence of the system parameters upon the output power is estimated.

Snf7 spirals sense and alter membrane curvature

Endosomal Sorting Complex Required for Transport III (ESCRT-III) is a conserved protein system involved in many cellular processes resulting in membrane deformation and scission, topologically away from the cytoplasm. However, little is known about the transition of the planar membrane-associated protein assembly into a 3D structure. High-speed atomic force microscopy (HS-AFM) provided insights into assembly, structural dynamics and turnover of Snf7, the major ESCRT-III component, on planar supported lipid bilayers. Here, we develop HS-AFM experiments that remove the constraints of membrane planarity, crowdedness, and support rigidity. On non-planar membranes, Snf7 monomers are curvature insensitive, but Snf7-spirals selectively adapt their conformation to membrane geometry. In a non-crowded system, Snf7-spirals reach a critical radius, and remodel to minimize internal stress. On non-rigid supports, Snf7-spirals compact and buckle, deforming the underlying bilayer. These experiments provide direct evidence that Snf7 is sufficient to mediate topological transitions, in agreement with the loaded spiral spring model.

3D printing of a versatile applicability shape memory polymer with high strength and high transition temperature

3D printing shape memory polymers (SMP) with high strength and high transition temperature (Tr) are widely demanded in many fields, such as the aerospace material. However, either the SMP with high Tr or the 3D printing such polymer remains challenging. Here, a cyanate ester based shape memory interpenetrating polymer network (IPN) was prepared successfully through both of digital light process (DLP) and direct ink writing (DIW) 3D printing. Significantly, the 3D printed shape memory polymer performs a highest reported tensile strength of 3D printing SMPs, which is up to 70 MPa. Besides, the high printing resolution and low volume contraction, the high Tr (about 170 °C), high modulus, and excellent shape memory effect (with average shape fixation ratio (>95%), and average shape recovery ratio (>86%)) allows the 3D printing SMP to perform a versatile applicability. The application of this 3D printing SMP was demonstrated by spiral spring with high modulus, deformable sealing ring for easy installation, and smart mold for the manufacturing of fiber composite with complex structure. This work provides a preparing strategy for 3D printing cyanate ester based SMP, which could be applied in broad fields.

Dynamic performance of a series elastic actuator with variable stiffness logarithmic spiral spring

Dynamic performance of a series elastic actuator with variable stiffness logarithmic spiral spring

Vibration Absorption using KDamper-based Devices with Extreme Geometric Nonlinearity

A KDamper oscillator is proven to be a more effective alternative to conventional Tuned Mass Damper (TMD) approaches and Quazi Zero Stiffness (QZS) or negative stiffness isolators. In this paper, an extended version of the KDamper (EKD) concept is employed to control the dynamic responses of an undamped (or low damper) SDoF system subjected to various dynamic loads. The KDamper consists of an additional mass, artificial dampers, and positive and negative stiffness elements. The additional implemented mass is one order of magnitude smaller as compared to most mass related vibration absorbers (TMDs, TMDIs, KDampers, etc.). The artificial dampers and the stiffness element values are selected following an engineering-criteria driven optimization procedure that accounts for geometric constraints and manufacturing limitations. The negative stiffness element is realized with an articulated mechanism that employs pre-stresses conventional stiffness elements (spiral springs) and generates controlled negative stiffness (NS). In order to exploit the advantages that the inherent nonlinear nature the NS offers, such as robustness, broadband response and energy sinks, the proposed dynamic vibration absorber is designed to present significant geometric nonlinearity, that varies from none (linear system) to extreme. Thus, different test cases are presented with respect to the desired nonlinearity of the generated NS, as well as to the type of the external load subjected to the structure. This way we can determine in which cases extreme geometric nonlinearity is beneficial to the dynamic behavior of the controlled structure.

Mechanical Conversion and Transmission Systems for Controlling Triboelectric Nanogenerators

Triboelectric nanogenerators (TENGs) are a promising renewable energy technology. Many applications have been successfully demonstrated, such as self-powered Internet-of-Things sensors and many wearables, and those portable power source devices are useful in daily life due to their light weight, cost effectiveness, and high power conversion. To boost TENG performance, many researchers are working to modulate the surface morphology of the triboelectric layer through surface-engineering, surface modification, material selection, etc. Although triboelectric material can obtain a high charge density, achieving high output performance that is predictable and uniform requires mechanical energy conversion systems (MECSs), and their development remains a huge challenge. Many previous works did not provide an MECS or introduced only a simple mechanical system to support the TENG integration system device. However, these kinds of designs cannot boost the output performance or control the output frequency waveform. Currently, some MECS designs use transmission conversion components such as gear-trains, cam-noses, spiral springs, flywheels, or governors that can provide the step-up, controllable, predictable, and uniform output performance required for TENGs to be suitable for daily applications. In this review, we briefly introduce various MECS designs for regulating the output performance of TENGs. First, we provide an overview of simple machines that can be used when designing MECSs and introduce the basic working principles of TENGs. The following sections review MECSs with gear-based, cam-based, flywheel-based, and multiple-stage designs and show how the MECS structure can be used to regulate the input flow for the energy harvester. Last, we present a perspective and outline for a full system design protocol to correlate MECS designs with future TENG applications.

Skyhook Control Law Extension for Suspension with Nonlinear Spring Characteristics

This work aimed to improve the vehicle body stability and the ride comfort of the tracked military vehicle crew. For this purpose, magnetorheological fluid dampers were used. This process has made the theoretical model of the tracked platform a semi-active suspension system. This modification allows for the application of different control laws to these systems. The usage of the continuous skyhook control law assumes the influence of three fictitious viscous dampers. Their force in this conceptual model is replicated by the magnetorheological dampers of the suspension in the real system. However, the continuous skyhook control law does not take into consideration the nonlinear stiffness characteristics. In this paper, the continuous skyhook control law has been appropriately modified. The modification takes into consideration the nonlinearity of the stiffness characteristics. Applying the modified continuous skyhook control law improves the stability of the vehicle body and the vehicle crew’s ride comfort. All these goals had to be introduced due to the modernization of the tracked military vehicle suspension by replacing the torsion bars with spiral spring packages with nonlinear characteristics.

Development of Parametric Modeling and Finite Element Analysis System for Cylindrical Spiral Tension Spring

The survey shows that there are few researches on automatic modelling and finite element analysis by changing the relevant parameters of cylindrical spiral tension springs. This paper discusses the method of combining parametric technology with finite element analysis, using Visual Studio 2010 as the system development platform and Visual Basic (VB) as the program development language to establish a VB window operation interface. Automated modelling is carried out through the input feature size, and the VB event-driven feature is used to link automated modelling and automated finite element analysis to establish a parametric design and finite element analysis system for cylindrical spiral tension springs.

A Novel Biopsy Capsule Robot Based on High-Speed Cutting Tissue.

The capsule robot (CR) is a promising endoscopic method in gastrointestinal diagnosis because of its low discomfort to users. Most CRs are used to acquire image information only and lack the ability to collect samples. Although some biopsy capsule robots (BCRs) have been developed, it remains challenging to acquire the intestinal tissue while avoiding tearing and adhesion due to the flexibility of colonic tissue. In this study, we develop a BCR with a novel sampling strategy in which soft tissue is scratched with sharp blades rotating at high speed to avoid tissue tearing. In the BCR design, a spiral spring with prestored energy is used to release high energy within a short period of time, which is difficult for a motor or magnet to perform within a small capacity installation space. The energy of the tightened spiral spring is transmitted to drive sharp blades to rotate quickly via a designed gear mechanism. To guarantee reliable sampling, a Bowden cable is used to transmit the user's manipulation to trigger the rotation of the blades, and the triggering force transmitted by the cable can be monitored in real time by a force sensor installed at the manipulating end. A prototype of the proposed BCR is designed and fabricated, and its performance is tested through in vitro experiments. The results show that the proposed BCR is effective and the size of its acquired samples satisfies clinical requirements.

Deformation Expression of Soft Tissue Based on BP Neural Network

This paper proposes a soft tissue grasping deformation model, where BP neural network optimized by the genetic algorithm is used to realize the real-time and accurate interaction of soft tissue grasping during virtual surgery. In the model, the soft tissue epidermis is divided into meshes, and the meshes generate displacements under the action of tension. The relationship between the tension and displacement of the mesh is determined by the proposed cylindrical spiral spring model. The optimized BP neural network is trained based on the sample data of the mesh point and vertical tension, so as to obtain the force and displacement of any mesh point on the soft tissue epidermis. The virtual experiment platform is built using a PHANTOM OMNI haptic hand controller and the 3D Max software, by which the simulation experiment of grasping the human abdomen is realized. The experimental results show that the proposed model has good visual interaction and real-time force feedback, which can meet the requirements of deformation simulation for soft tissue grasping in virtual surgery.

Technology Status and Development Trend of Modular Moving System

With the development of technology, modular independent suspension technology has been widely applied on high-movement off-road platforms in the developed world because of the characteristics of offline assembly and full-body lifting. At the same time, after the breakthrough of key techniques such as the stiffness spiral springs, the high dissipation of the shock absorbers, the lightweight of double-wishbone steering mechanism and the non-maintenance bearing, the ability to carry the off-road mobility and armor protection of the military vehicles have been significantly increased. In this case, the application of the modular independent suspension and its current state around the world was explained, that the development of this technology is of great significance to the off-road maneuvering of our military equipment was also represented in this paper.

Development of the Auto-Fit Dial and its application to protective vests

This study proposes the Auto-Fit Dial, which is suitable for high-speed fitting; it includes a function that can wind wire at high speed using an energy storage–release mechanism. The Auto-Fit Dial can store energy in advance in the spiral spring via the rotation of the knob cover, and it releases the stored energy to wind the wire when required by pushing the knob cover. Firstly, the concept design and working principle of the Auto-Fit Dial are explained. Next, a detailed design and structural stability analysis of the mechanical components are described based on the design formula and finite-element analysis. An Auto-Fit Dial prototype is manufactured according to the detailed design with the weight, diameter, and height of 9.7 g, 30.5 mm, and 16.7 mm, respectively. The maximum number of rotations is 5.2 turns, which can wind a wire up to a length of 320 mm. The pulling force applied when the Auto-Fit Dial pulls the wire is initially measured as 5.10 N. The time required to wind a 320 mm wire is 0.015 s, which results in an average speed of 21.33 m/s. Moreover, the Auto-Fit Sleeve is fabricated and applied to the arm sleeve to verify the utility of the Auto-Fit Dial, which combines wire and fabric. Finally, the Auto-Fit Vest is developed by applying a protective vest to the Auto-Fit Dial.

Dynamic simulation of the Wilberforce pendulum using constrained spatial nonlinear beam finite elements

AbstractMore than 100 years ago, Lionel Robert Wilberforce did investigations On the Vibrations of a Loaded Spiral Spring [1]. The spring was clamped at its upper side and on the other side, perpendicular to the spring axis, a steel cylinder was attached. Four screws with adjustable nuts were symmetrically attached around the cylinder in order to change its moment of inertia (Fig. 1). In this paper the Wilberforce pendulum is modeled by a rigid body attached to a constrained spatial nonlinear Timoshenko beam, discretized with B‐spline shape functions. As shown by a numerical experiment, the presented model is capable of reproducing the characteristic pendulum motion.

Characteristics of a novel cylindrical arm spiral spring for linear compressor

The spring system is the key component of linear compressor, which is attractive in the field of household refrigeration due to its high efficiency and compact structure. Inspired by the traditional flexure spring, we proposed a novel cylindrical arm spiral spring for linear compressor with a comprehensive consideration on the cost, compactness and performance requirements. The design method of spring was introduced and different performance can be obtained by adjusting the internal radius, external radius, number of turns and wire diameter. The static displacement of spring was modelled by using FEA (Finite Element Analysis) method for various axial and radial force. And a specific fixture was built to measure the spring stiffness to verify the results obtained from FEA simulation. At last, the dynamic test of the linear compressor equipped with the proposed spring was conducted. The experimental results showed that the resonant frequency of linear compressor can meet the design requirements of 78 Hz without gas compressor, indicating that the application of this type of spring in the linear compressor is feasible.

Study on the static properties of spiral springs under static loading

Study on the static properties of spiral springs under static loading

Highly efficient pyroelectric generator for waste heat recovery without auxiliary device

Waste heat is very abundant and widespread in our lives. Using pyroelectric generators (PEG) to capture the ambient heat energy is meaningful. Here we fabricated a highly efficient PEG using nanocomposite. The nanocomposite was made of P(VDF-TrFE-CFE) and barium strontium titanate (BST) nanoparticles and boron nitride (BN) nanosheets, which has excellent thermal conductivity and high polarization. The output current density of PEG can reach 1.7 μA/cm2, it is a great improvement for PEG devices. In addition, we present a new evaluation method for standardizing the performance of a PEG, which is use η (the ratio between the power density and the heat flux) as the thermos-electric conversion efficiency of PEG. Furthermore, a PEG-unit was designed and fabricated, which was cleverly connected by PEG and a plane spiral spring, it can better utilize external vibration to realize waste heat recovery without auxiliary device. The PEG-unit can be used for energy recovery in the process of train running and it can light up the LED lamp bead for 10 s within five minutes operation.

Design and experiment of a SMA-based continuous-stiffness-adjustment torsional elastic component for variable stiffness actuators

The variable stiffness actuator (VSA) is widely applied in robotics and human-robot interactions, generating controllable torque with sufficient compliance to ensure safety and robustness. At present, typical VSA design usually adopted pure mechanical structures that integrated an additional motor for stiffness adjustment, making it hard to meet the demand of lightweight joint actuation due to large actuator size and weight. As a new functional material, shape memory alloy (SMA) shows the prospect of lightweight actuation due to its high power-to-weight ratio. In this paper, a compact SMA-based torsional elastic component (SMA-TE) for the VSA is proposed. The SMA-TE with torsional stiffness is implemented by the confrontational arrangement of paired spiral SMA springs. The ceramic heating plate and semiconductor refrigeration plate are installed in the elastic component shell, and the thermally conductive medium is filled between the internal gap. The torsional stiffness of the SMA-TE can be continuously adjusted via a feed-forward cascade controller. Repeated experimental results show that the SMA-TE can precisely maintain constant stiffness and continuously adjust its stiffness between 2.6 Nm rad−1 and 6.8 Nm rad−1 when performing precise square wave stiffness tracking under variable frequencies.

Base-isolated steel structure with spring limitersunder near-fault earthquakes: Experiment

The seismic performance of a steel frame base-isolated structure with steel spiral spring limiters is experimentally investigated under near-fault ground motions. A series of shake table simulator tests are carried out to analyze the dynamic response of isolation layer and superstructure. The test setup consists of a one-eighth scale five-story steel frame with steel spiral spring limiters that are designed and modeled in different parameters and stiffness, as well as various reserved gap sizes between the testing structure and limiters. The main output parameters are the maximum deformation at the isolation level, the maximum vertical force of isolation bearings, and inter-story drift. The results further reveal the seismic impact on the isolation layer and superstructure dynamic response caused by the limiter stiffness and reserved gap size.

Implementation of Product Sales Forecast Using Artificial Neural Network Method

Product sales forecasting is used by companies to estimate or predict future sales levels using sales data in the previous year. The Artificial Neural Network Backpropagation Algorithm can forecast the sales of goods for the next period for each item in the company. The forecasting process begins by determining the variables needed in the network pattern, and then the established network pattern continued in the network training process using the backpropagation algorithm. After carrying out the network training process, the researcher comparisons with several network patterns formed. This research was conducted to discuss the forecasting analysis of PT XYZ products on spiral and leaf springs. Forecasting carried out on Toyota 48210-25290 R3 type leaf springs using the Artificial Neural Network Backpropagation method with a learning rate weight value of 0.1 hidden layers four and an error of 0.01. From the data processing analysis that has been carried out based on the weight parameters selected, the prediction of sales in April.