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Open coil springs are designed to provide expansion force, as indicated in the opening spaces. The super elasticity of Niti arch wires and springs allows the orthodontist to apply almost continuous light force with larger activations, resulting in reduced tissue trauma. However, indirect factors like high or low temperature should be monitored as an essential part of applying any force using open coil springs. These temperature differences may influence the springiness, corrosion, and efficacy of Niti coil springs over time. The aim of this study was to evaluate the force rate of NITI open coil springs compressed from 15.0 mm to 8.5 mm after exposure to high (45 ± 3 °C) and low temperature (10 ± 3°C). Forty-five samples of 15.0 mm long Niti springs were divided into 3 groups (n = 15). Group A was immersed in artificial saliva at 37º C for 21 days. Group B was immersed in hot water (45± 3 °C). Group C was immersed in cold water (10± 3 °C). The springs were then subjected to a compression test using a Manual Digital Force Gauge at 43% of the initial size (pre-stretched). Subsequently, the springs were compressed from 15.0 mm to 8.5 mm, and the data were recorded at Day 0, 1, 10, and 21. The analysis of variance revealed p-values below 0.05 for the four-time frames: initial test (0.046), after 24 hours (0.007), after 10 days (0.082), and after 21 days (0.038), indicating significant differences in the force rate of Niti open coil springs when immersed in different temperatures. Additionally, significant differences were found among the different pairings of the three tested groups. The force rates of open coil springs with low temperature were statistically different across different time frames. However, high temperature affected the coil springs more significantly than low temperature. There were significant differences in the force rate of Niti open coil springs when immersed in different temperatures. [ABSTRACT FROM AUTHOR]

This research focuses on improving vehicle safety by developing a new spring-based energy absorption system for the front bumper of a Bolero vehicle. The goal is to reduce the severity of frontal collisions by absorbing a significant portion of the impact energy. The proposed system comprises a helical compression spring, a mounting bracket, and a chassis member. This design aims to absorb 30-35% of the energy impact, reducing the deceleration rate and minimizing the shock transmitted to the passenger cabin. To visualize the system and estimate its energy absorption capabilities, a 3D CAD model and analytical calculations have been performed. Further analysis using finite element methods will provide a more detailed understanding of the deformation behaviour of the bumper and spring, as well as the energy absorption capacity of the shock absorbing. Future work will involve refining the design, conducting detailed analysis, and evaluating the performance of the system through rigorous testing. This research has the potential to significantly enhance vehicle safety and mitigate the risks associated with frontal collisions. Major Findings: A novel spring-based impact energy absorption system was proposed to reduce the severity of frontal collisions by 30-35 %. Finite element analysis was conducted to assess the system's deformation behaviour and energy absorption capacity. The four-damper system demonstrated a 42.44% reduction in maximum deformation compared to a plain bumper. The proposed system has the potential to significantly enhance vehicle safety [ABSTRACT FROM AUTHOR]

This study investigates the tensile performance of 3D-printed helical springs through experiments, numerical simulations, and analytical methods, optimized with an optimization algorithm. Rapid fabrication of specimens using additive manufacturing technology is followed by tensile experiments to obtain load–displacement curves and stiffness. Analytical and numerical models predict the tensile performance, with Liu's model exhibiting the highest accuracy. Research indicates that it is highly necessary to consider geometric nonlinear effects when predicting the tensile performance of helical springs. A multi-objective particle swarm optimization (MOPSO) algorithm is applied to maximize tension stiffness and minimize weight, considering four key geometrical parameters as design variables. [ABSTRACT FROM AUTHOR]

Objective: The study aims to identify characteristics that impact the postoperative prognosis and recurrence of intracranial dissecting aneurysms (IDA) patients treated using multi-stent overlapping techniques. Methods: Clinical data from 69 IDA patients treated with multistate-assisted spring coil embolization at the hospital between January 2017 and October 2023 were retrospectively reviewed, including clinical and imaging data gathered at admission and discharge. The prognosis was determined based on mRS grade at discharge, and the patients were divided into excellent prognosis (mRS 0–2 points) and poor prognosis (mRS 3–6 points). They were split into two groups: recurrence and no-recurrence, based on whether the patients had recurrence during surgical follow-up. The patient's clinical information and aneurysm data were compared between the two groups to better understand the efficacy of multi-stenting for IDA and to investigate the factors that influence the good or negative prognosis of multi-stenting for IDA and recurrence. Results: The prognosis was poor in 10 patients, 7 of whom died, while 59 had an excellent prognosis. Hunt-Hess classification (χ2 = 25.503a, P = < 0.01), hospitalization days (t=-3.873, P < 0.01), operation time (t=-1.970, P = 0.049), and aneurysm height (t=-1.969, P = 0.049) were all significant. 62 patients were discharged with 4 postoperative recurrences and 58 without recurrences in patients treated with multiple stents, with significant differences in the largest diameter (t=-2.235, P = 0.025), basal length (t=-2.149, P = 0.032), and position(located in pica base or not) (χ2 = 10.955a, P = 0.001). The postoperative recurrence rate was 5.8%, but 85.8% reported satisfactory neurologic function (mRS ≤ 2). The case fatality rate was 10.1%. Conclusion: Hunt-Hess grading on admission, aneurysm high, and operation time affect the prognosis of IDA, Hunt-Hess grade was an independent risk factor for prognosis. Aneurysm size, longest diameter, basal length, and location at the base of the pica affect recurrence. Located in pica base by the dissecting aneurysm is an independent risk factor for recurrence. [ABSTRACT FROM AUTHOR]

An optimization algorithm based on SLSQP solver was created to design helical compression springs. The goal is to reach the required behavior even when the standards formula is inaccurate. Indeed, it was already shown in previous works that the classic formula determining the global load-length behavior of the spring is not always accurate enough because it does not consider the effects of the spring's ends, in particular for springs with low index and low number of coils. Based on a new tri-linear model, this algorithm finds optimized spring design which respects the required operative points. In order to test the algorithm, the first tests were carried out to optimize the design of a PLA 3D-printed spring. It was shown that the initial design stiffness is overestimated by over 28% by the formula extracted from the standards. Then, the design of the spring was implemented in the algorithm to optimize the pitch and the number of active coils. The experimental curve of the optimized design spring goes through the target behavior, with a non-linearity at the beginning of the deflection. The experimental error about the final stiffness is successfully reduced to 1.1%. It is hoped that this work will provide a valuable progress to assist engineers and manufacturers in helical spring design. [ABSTRACT FROM AUTHOR]

Springs are the most basic mechanical elements used in transmission mechanisms. The rapid development of the computer and cellular industry has encouraged spring manufacturers to develop the industry to produce very small springs. Most computer-aided design programs for mechanical parts provide the possibility of designing these parts, as these programs include different types of decisions. All these decisions require coordinates for geometric data as well as metadata. The paper aims to develop software programs to design and analyze springs as one of the most significant mechanical elements used. This paper aims to develop a design software of a helical spring system, where this software is built using a computer program in the language of Visual Basic Version 5. When the user enters data into the system, the system will perform a series of complex calculations in the system, then provide a detailed report on all the engineering dimensions of the spring, and test its efficiency. The output of the software shows the required spring wire parameters. The software was tested with test data from the open literature, and the required wire spring parameters were obtained. [ABSTRACT FROM AUTHOR]

Purpose: Dynamic response of helical spring structures is a focus of attention for dynamic analysis of flexible multi-body system (FMS) involving periodical vibration at high frequencies. In many finite element models, elemental shape functions are adopted to interpolate shapes of the structure with spiral shapes and large curvatures, which would result in a complicated modeling process and enormous degrees of freedom. In view of this, a high-efficiency helical spring structure model for dynamic analysis of FMS is proposed in this paper. Method: The paper presents a high-efficiency helical spring structure model for dynamic analysis of FMS, where helical radius, azimuth angles, height coordinates and torsion angles at one node of each coil are chosen as variables. Strains irrelevant to rigid motions of cross sections and virtual deformation power of the curved beam with geometrical nonlinearity are adopted. And a special shape function that can naturally satisfies the rule of equations of helical curves is constructed to minimize the errors of model for the helical spring. In addition, a model smoothing method is applied to modify the dynamic equation of the spring element, which can improve the computational efficiency obviously. Results: Four examples are considered to evaluate the effectiveness of the proposed spring element. Conclusion: In this paper, the helical spring is modeled as a whole, featuring clear and fewer descriptive variables, facilitating rapid calculation iteration and parametric modular design of the helical spring’s dynamic stiffness in the practical engineering. Additionally, for structures maintaining a regular shape during deformation, characteristic parameters that describe their shape rules are chosen as the descriptive variables. With the help of the specific mathematical relationships between these descriptive parameters and the structure’s shape, a shape function would be obtained that describes strongly geometrically nonlinear structures with minimal model error and fewer degrees of freedom, and this approach is universally applicable, which can be extended to various similar practical modeling applications. [ABSTRACT FROM AUTHOR]

Tendrils of climbing plants possess a striking spring-like structure characterized by a minimum of two helices of opposite handedness connected by a perversion. By performing tensile experiments and morphological measurements on tendrils of the climbing passion flower Passiflora discophora , we show that these tendril springs act as coil springs within the plant's attachment system and resemble technical coil springs. However, tendril springs have a low spring index and a high pitch angle compared with typical metal coil springs resulting in a more complex loading situation in the plant tendrils. Moreover, the tendrils undergo a drastic shift from the fresh turgescent stage to a dried-off and dead senescent stage. This entails changes in material properties (elastic modulus in tension), morphology (tendril and helix diameter, number of windings), anatomy (tissue composition), and failure behavior (susceptibility to delamination) and reduces the degree of elasticity and strain at failure of the tendrils. Nevertheless, senescent tendrils remain functional as springs and maintain high energy dissipation capacity and high break force. This renders the system highly energy efficient, as the plant no longer needs to metabolically sustain the died-back tendrils. Because of its energy-storing spring system, its high energy dissipation and high safety factor, the attachment system can be considered a 'fail-safe' system. The use of coil springs as mechanical devices is not restricted to man-made machinery; striking spring structures can also be found within the attachment systems of climbing plants. Passiflora discophora climbs by using long thin tendrils with adhesive pads at their tips. Once the pads have attached to a support, the tendrils coil and form a spring-like structure. Here, we analyze the form and mechanics of these 'tendril springs', compare them with conventional technical coil springs, and discuss changes in the tendril springs during plant development. We reveal the main features of the attachment system, which might inspire new artificial attachment devices within the emerging field of plant-inspired soft-robotics. [Display omitted] [ABSTRACT FROM AUTHOR]

AbstractThe significant dynamic responses of helical springs are widely reported as the main reason causing pre-failure in various high-speed conditions. Though the concept of nonlinear springs is proposed to reduce their own dynamic responses, they are found to induce unexpected spike forces during operations. This study presents a dual springs system used within high-speed sports car engines, which aims to mitigate the dynamic responses and spike forces. Analytical models are first developed to calculate the fundamental frequencies of the outer and the inner springs of the system. Then, a transient finite element (FE) model is developed to accurately simulate the dual springs system working at various high engine speeds and validated experimentally by the results of the engine head tests. The simulations reveal that the use of dual springs with different natural frequencies can mitigate the dynamic responses of the whole system to a certain extent. Nevertheless, it is still a compromise as coil clash occurs on each isolated spring though the effects are reduced. The findings of this study indicate that the establishment of direct connections between every component spring would be a promising way to better mitigate the dynamic responses including the effects of coil clash. [ABSTRACT FROM AUTHOR]

Leghold traps are an essential tool for managing brushtail possums (Trichosurus vulpecula) in New Zealand. However, the currently used trap design (No 1 double coil spring traps, often called Victor-type traps) has escape rates of up to 26%. This study focussed on addressing the high escape rate to improve the usefulness and acceptability of these traps. Specifically, modifications were made to the anchoring chain of the standard No 1 trap by adding one or two springs. These springs were designed to reduce the forces exerted by an animal during escape attempts. Over approximately 300 trap nights per trap configuration (unmodified No-Spring, 1-Spring, 2-Springs), the capture rates (proportion of animals caught and held until inspection) were measured. The results showed that traps with one or two springs achieved a significantly higher capture rate of 92%, compared to only 74% for the standard devices. The chain springs increased the capture rate by 24% due to a 69% reduction in escape rate. This study demonstrates that a minor modification (addition of one or two springs) to the restraining chain of No 1 double coil spring leghold traps greatly enhances their efficacy for capturing and managing possums. [ABSTRACT FROM AUTHOR]

The manufacturing industry's energy demands and the need for continuous improvement in compact, lightweight machines with mechanical resistance requirements require improvements in design. The objective is to obtain designs that occupy a smaller volume and have acceptable physical characteristics for the required function. This is achieved by implementing optimization techniques that yield the minimum value of an objective function constrained by the physical requirements of the problem. This work proposes the use of metaheuristic optimization techniques to find the dimensions that determine the smallest volume of a closed coil helical spring, which is found in industrial and automotive applications, respecting the physical and technical criteria that describe the design of these elements. The results demonstrate that the VSA identifies the optimal solution to the problem in a significantly shorter processing time than other techniques, with a volume reduction of 0.1% to 0.54%. The Inventor® software is used as a validation method of the solution, where a finite element analysis is carried out to verify that the mathematical model proposed adequately represents the problem and complies with the restrictions described in the mathematical model. Optimization algorithms together with simulation techniques are a useful tool in the design of machine elements, as they reduce computation and processing times, allowing solutions to be found that minimize production costs without neglecting the technical constraints of each problem. [ABSTRACT FROM AUTHOR]

The premature loss of primary teeth can lead to significant orthodontic issues, including the loss of space and improper alignment of permanent teeth. Space regainers, particularly non-compliant ones, are orthodontic devices designed to restore lost space without relying on patient compliance. These devices are especially valuable in pediatric orthodontics, where maintaining patient cooperation can be challenging. This report aims to demonstrate the use of non-compliant space regainers, specifically an open coil spring and AJ Wilcock wire, to recover space following the early loss of the upper second deciduous molar. Additionally, the effectiveness of these devices in addressing crossbite and correcting molar relations will be assessed. A case study was conducted on a pediatric patient who experienced the premature loss of the upper second deciduous molar. Non-compliant space regainers, including an open coil spring and AJ Wilcock wire, were utilized to distalize the molars and correct the crossbite using a transpalatal arch (TPA). Treatment progress was monitored, with final evaluations scheduled after the eruption of the premolars to assess the completeness of molar relation and crossbite correction. The use of open coil spring and AJ Wilcock wire successfully regained space, with significant improvements in molar relation and crossbite correction. The results closely matched the planned treatment goals. Further correction of the molar relation and crossbite will be evaluated post-eruption of the premolars. Non-compliant space regainers provide a dependable solution for managing space loss and crossbite, particularly in situations where patient cooperation is difficult. These devices have proven to be effective in achieving early correction, reducing the need for more complex orthodontic procedures. Continued research is needed to optimize the use of non-compliant space regainers and evaluate their long-term efficacy in various orthodontic scenarios. [ABSTRACT FROM AUTHOR]

The paper aims to study the dynamic behavior of an elastic mechanical system without damping consisting of two masses m1 and m2 mounted on a cantilever beam subjected to bending and supported on two helical compression springs, or the influence of the dynamic mass absorber m2 on the pulsation characteristics of the forced bending vibrations of the mass electric motor m1. Using the MATHCAD professional program, the influence of the mounting method of the dynamic absorber on the elastic system's own pulsations can be determined. [ABSTRACT FROM AUTHOR]

The paper aims to study the dynamic behavior of a hybrid elastic system without damping consisting of a beam in a cantilever supported on helical compression springs on which an electric motor is mounted. With the help of the MATHCAD professional program, the influence of the relative stiffness of the elastic bar subjected to bending and the springs subjected to compression was simulated, on the natural pulsation, the amplitude of the vibrations and the dynamic factor of the forced vibrations for two assembly variants of the electric motor [ABSTRACT FROM AUTHOR]

The thickening mill equipment installed on the second floor is damage for the structural and personal health. In this study, the vibration conditions of thickening mill equipment and its vibration isolating based on MR damper technology are investigated experimentally and simulacrum. First, the vibration test of thickening mill equipment installed on rigid foundations is operated, and the results show that while the rigid foundation can suppress equipment vibration, it also deteriorates vibration transmission to the ground, which results in vibration displacement of the ground exceeds the permissible range by 120%. Second, a MR damper utilized to form the elastic foundation is tested to acquire the force–velocity characteristics, which is described by the proposed Bingham model. The comparison results between the model predicted and measurement data delicate that can effectively describe the correlation between the dynamic properties of MR damper and the coil current/excitation conditions. Finally, an elastic foundation consisting of eight coil springs and several MR dampers is proposed to replace the rigid foundation of the thickening mill equipment. Together with the ON–OFF skyhook control algorithm, the properties of the elastic foundation to reduce the force transmission rates are tested based on the simulation model. The simulation results suggest that the designed elastic foundation can effectively reduce the vibration transmission from the thickening mill equipment to the ground, which can decrease the peak force transmission rate by 95.5%. This study provides a guide to technological transformation methodology of the thickening mill equipment to reduce structural vibration. [ABSTRACT FROM AUTHOR]

AbstractThis article proposes a glass fiber reinforced plastic (GFRP) wave spring and conducts a study on its free and constrained vibration characteristics and compression performance. Initially, a stiffness prediction model for composite wave spring is established using laminated plate theory and Moore’s theorem. Additionally, the failure mode of the composite wave spring was predicted and experimentally confirmed using ABAQUS and the 3D-Hashin failure criterion. Finally, the vibration characteristics of composite wave spring and metal helical spring are investigated using the B&K testing system in both free and constrained states. The experimental stiffness and ultimate load of the composite wave spring are 20.67 N/mm and 1386.67 N. The composite wave spring exhibits good vibration reduction performance in both free and constrained states, with maximum vibration attenuation amplitudes of 122.71 and 144.93 dB. In comparison, the metal helical spring has maximum vibration attenuation amplitudes of 41.65 and 111.89 dB. [ABSTRACT FROM AUTHOR]

This research focuses on cylindrical helical springs with circular cross-sections made from carbon steel (SH 0.82% C) and stainless steel (AISI 302). The transformation from a linear bar to a circular spiral involves numerous factors such as material mechanical behavior, stress–strain relationships and residual stresses. This research investigates the spring-back phenomenon, which affects the final diameter of helical springs post-manufacture, using analytical, experimental and numerical methods. An analytical model, derived from the mechanical bending process, was proposed to predict spring-back, and its accuracy was validated against experimental data. This study also employed finite element simulations to analyze elastic recovery, confirming the analytical predictions. Results indicated that the spring-back ratio k could be expressed as an exponential function of the spring index C (the ratio between the final diameter of the spring D2 and the diameter of the wire DW), with a maximum error of 4.80% for stainless steel and 3.62% for carbon steel. This study's findings provide valuable insights into optimizing the spring manufacturing process, enhancing the precision of spring diameter predictions, and potentially reducing production errors and material waste. [ABSTRACT FROM AUTHOR]

Objective: Canine retraction after first premolar extraction is a prevalent orthodontic procedure. This systematic review aimed to evaluate the efficiency of NiTi coil springs and elastomeric chains for canine retraction and assess the side effects of each technique. Methods: Two reviewers conducted an electronic search of online databases (Medline, Science Direct, Scopus, and Web of Science) and a manual search up to May 8th, 2024, without language restrictions. Only randomized clinical trials (RCTs) were included. The same reviewers assessed the quality of the studies using the Cochrane risk of bias tool for randomized trials. Due to the heterogeneity of data, conducting a meta-analysis was not feasible. Results: Initially, 2400 records were identified. After evaluating the titles and abstracts, the full texts of 40 studies were reviewed. Eleven RCTs complied with the study selection criteria and were included in the review. The results indicated a faster space closure rate exhibited by NiTi coil springs compared to elastomeric chains. The rate of anchorage loss varied depending on the anchorage devices used. More tipping and rotation were observed with NiTi coil springs. There was no statistical difference between the two groups regarding root resorption, pain intensity, and plaque control. Conclusions: The results indicated a slightly faster space closure rate with NiTi coil springs compared to elastomeric chains but at the cost of greater tipping and rotation. No significant differences were observed between the NiTi closed coil spring and elastomeric chain force delivery systems in the other evaluated parameters. [ABSTRACT FROM AUTHOR]

On a flat city road, the specificity of the suspension poses a challenge. Sport utility vehicles (SUVs) have less flexibility compared to regular cars, despite providing a firm grip on asphalt and concrete. Constant adjustments to the center of gravity of SUVs are necessary. Surprisingly, they are less reliable and stable in urban settings due to this characteristic. In this study, a mathematical model of the suspension system of SUVs based on the Newtonian approach is introduced and validated with data from experiments carried out by the MTS machine system on the mono-tube (oil/air) mixed damper element. The model accurately predicts the performance of this damper, commonly used in SUVs, across various operating conditions, including different frequencies. A coil spring element, serving as a passive suspension unit with this damper, is also tested experimentally under similar conditions. By integrating passive suspension elements with the active actuator, the proposed modified design reduces the power consumption needed for the actuator to function and ensures a certain level of reliability. The effectiveness and performance of the modified active suspension system in comparison to the traditional passive suspension system are assessed using three different strategies: hybrid PID-LQR, linear quadratic regulator (LQR), and proportional-integral-derivative (PID). The genetic algorithm is utilized to determine the optimal parameter values for each controller by minimizing a cost function, maximizing performance, and minimizing energy consumption. Simulation results demonstrate that the active suspension system controlled by the PID-LQR controller offers significantly improved ride comfort and vehicle stability compared to other systems. This suggests that the performance of the active suspension system is greatly enhanced by the combined application of the hybrid PID-LQR controller compared to other systems. [ABSTRACT FROM AUTHOR]