Simple Spring Research Articles

Prediction of flanking sound transmission through cross-laminated timber junctions with resilient interlayers

While the low weight and high bending stiffness of cross-laminated timber (CLT) are key to its popularity, these properties also contribute to poor acoustic performance. Notably flanking sound transmission is a critical factor, driving the need for vibration reduction solutions such as resilient interlayers in the junction design. However, due to the complex material behavior of CLT and resilient interlayers, the improvement related to these solutions is difficult to predict. In this research, an analytical model with low computational cost is developed to evaluate the vibration reduction index Kij for CLT junctions with resilient interlayers. The CLT panels are considered as thin orthotropic plates with homogenized material properties. Three potential material models are proposed for the interlayer: it is considered as a thin plate, a thick flexible layer with out-of-plane motion governed by shear or distributed springs. The prediction model is experimentally validated for junctions consisting of CLT panels, with and without resilient interlayers. For junctions without interlayers, the predicted and experimentally determined vibration reduction index Kij correspond most closely when the junction is realized with stiff connectors. In this case, the predictions are moderately accurate with deviations below 5 dB in 1/3 octave bands up to approximately 2000 Hz for both corner and coplanar transmission paths. For junctions with resilient interlayers, the shear interlayer model exhibits the best performance with deviations of less than 5 dB in most 1/3 octave bands. For frequencies below 1000 Hz, the accuracy of the simplified spring model is comparable to that of the thick layer model. Simulations with equivalent isotropic material parameters yield slightly inferior predictions than for orthotropic parameters if the degree of orthotropy of the panels is high.

Assessing the equivalent spring modelling method of CFS elements encased in ultra-lightweight concrete

An efficient finite element approach was recently developed to analyse encased cold-formed steel (CFS) structures. This new technique replaced encasing material with unidirectional springs, analogous to the Winkler foundation concept, to shorten the analysis time while ensuring accuracy and reliability in predicting the structural behaviour of encased CFS components. In this paper, the validity, and limitations of the simplified spring model to represent outstanding plates were assessed. The investigation demonstrated that the simplified spring model could effectively predict the ultimate load for a wide range of ultra-lightweight concrete moduli (50-250 MPa) with an acceptable error. The analysis indicated that plate elements initially in cross-section class 4 without encasing material become at least class 3, or better as a consequence of encasing. Previously reported experiments were used to evaluate the performance of the ESM. The analysis demonstrated that the ESM can accurately predict the local failure ultimate load of encased CFS sections with an acceptable error percent and significantly less computational effort than a 3D solid model.

Ferroelastic twin walls for neuromorphic device applications

The possibility to use ferroelastic materials as components of neuromorphic devices is discussed. They can be used as local memristors with the advantage that ionic transport is constraint to twin boundaries where ionic diffusion is much faster than in the bulk and does not leak into adjacent domains. It is shown that nano-scale ferroelastic memristors can contain a multitude of domain walls. These domain walls interact by strain fields where the interactions near surfaces are fundamentally different from bulk materials. We show that surface relaxations (∼image forces) are curtailed to short range dipolar interactions which decay as 1/d2 where d is the distance between domain walls. In bigger samples such interactions are long ranging with 1/d. The cross-over regime is typically in the range of some 200–1500 nm using a simple spring interaction model.

Enzyme Engineering by Force: DNA Springs for the Modulation of Biocatalytic Trajectories.

The engineering of enzymatic activity generally involves alteration of the protein primary sequences, which introduce structural changes that give rise to functional improvements. Mechanical forces have been used to interrogate protein biophysics, leading to deep mechanistic insights in single-molecule studies. Here, we use simple DNA springs to apply small pulling forces to perturb the active site of a thermostable alcohol dehydrogenase. Methods were developed to enable the study of different spring lengths and spring orientations under bulk catalysis conditions. Tension applied across the active site expanded the binding pocket volume and shifted the preference of the enzyme for longer chain-length substrates, which could be tuned by altering the spring length and the resultant applied force. The substrate specificity changes did not occur when the DNA spring was either severed or rotated by ∼90°. These findings demonstrate an alternative approach in protein engineering, where active site architectures can be dynamically and reversibly remodeled using applied mechanical forces.

Efektifitas Plat Ekspansi dan Simple Spring

Improving occlusion and tooth alignment can be achieved through orthodontic treatment. Orthodontic appliances can also correct crowded teeth, which are common in Indonesia. The aim of this study is to assess the effectiveness of using expansion plates to create space and simple springs to correct the malposition of anterior teeth in the upper and lower jaws, specifically teeth 11, 31, and 41. A 22-year-old female patient with an overjet of 4.2 mm and an overbite of 2.7 mm. First molar relationship on the right and left sides: Angle's Class I. Canine relationship on the right and left sides: Class I. Malposit ion of the patient's individual teeth: 11 (distolabioversion), 15 (mesiopalatotorsion), 23 (mesiolabioversion), 25 (mesiopalatotorsion), 31 (mesiolingualversion), 33 (mesiolabiotorsion), and 41 (distolabioversion). Lateral expansion of 0.85 mm will be performed and tooth malpositions will be corrected using an active plate in the form of a simple spring on teeth 11, 21, 31, and 41. Tooth malpositions on elements 11 distolabioversion (corrected), 31 mesiolingualversion (corrected), and 41 distolabioversion (corrected). During visits 16 to 20, the operator performed retraction by activating a labial arch. There was a change in overjet from 4.2 mm to 3.15 mm. The treatment was effective in correcting the malposition of teeth 11, 31, and 41. The patient exhibited tooth movement mesially towards the labial direction, thus correcting the patient's teeth towards the ideal position.

Correction of Maxillary Multiple Diastem and Mandibular Crowding with Removable Orthodontic

Crowding and diastema are common malocclusion conditions that occur due to a discrepancy between tooth size and jaw size. The treatment that can be done is based on the severity of the case. Mild cases of malposition can be treated with removable orthodontic appliances. This article aims to show the analysis how an active plate device with a simple spring was used to treat multiple maxillary diastemas and anterior crowding of the mandible. The patient complained that his upper front teeth gap and his lower teeth were crowded. It does not interfere with the appearance, but sometimes open food is tucked between the front teeth. The patient has never used an orthodontic appliance before. Molar relation: Malocclusion Angle class 1 type dental with mild individual tooth malposition. Twenty-two treatment visits were performed. Treatment was carried out using an active plate with a simple spring on teeth 13, interdental 31-41, and 43; retentive components using Adam Clamer on teeth 16, 26, 36, and 46; long labial arch with U loops on the right and left permanent 1st premolar teeth. In the 22nd control, the results showed that teeth 11, 21, and 43 malpositions were corrected, and the diastema was closed on tooth 14 against 13 and tooth 21 against 22. In addition, the width of the diastema on interdental 13-12, 12-11, and 22-23 was reduced to 0.05 mm. An active plate with a simple spring can correct diastema and mild crowding of the anterior teeth

Building a mathematical model for a simple harmonic oscillator that uses educational methods found in both physics education research and in the language disciplines that make it accessible to undergraduate students in an introductory musical acoustics course

At the basis of any course in acoustics is the fundamental idea of the simple harmonic oscillator. The term alone is confusing to students with little to no background in physics or math. For courses in musical acoustics at the undergraduate level, this topic is often minimized due to the lack of preparation. This, in turn, results in a more superficial approach to the advanced topics. While deriving the mathematical treatment from first principles is out of reach to these students, approaching the math itself as a language where they are building a description of a simple mass and spring system in their new, yet somewhat familiar, language can be accomplished through pictures, graphs and hands on activities. Students begin to build a vocabulary of “words” that can be strung together in “sentences” that tell the story of how the motion of a mass on a spring is produced. Emphasis is placed on the analogous comparison of physical properties by relating variables such as amplitude and frequency to that of volume and pitch. This model can then be used as a building block to the understanding of how sound is produced, propagated and perceived.

Mesoscopic irreversible thermodynamics of aging kinetics of alpha polypeptides [DNA] under various constraints: Special reference to the simple spring mechanics

The mesoscopic irreversible thermodynamic treatment of α-polypeptides and the helical polynucleotides (DNA) furnishes two sets of analytical expressions, which allow us not only to analyze the reversible force–extension experiments performed by atomic force microscopy (AFM) but also to predict the irreversible “aging” kinetics of the single-stranded and double-stranded polynucleotides (ssDNA and dsDNA) helical conformations exposed to aqueous solutions and applied static stress systems under the various constraints. The present physicochemical cage model emphasizes the fact that the global Helmholtz free energy of the helical conformation acts not only under the stored “intrinsic” unusual torsional and bending elastic energies inherited by the unfolded helical structure of the amino-acid (peptides) or the nucleic-acid (nucleotide) backbone but also reveals the importance of the interfacial Helmholtz free energy density associated with the interaction of the side-wall branches within the surrounding aqueous solutions. The analytical expression obtained for the unfolding force vs extension (FE) shows a strong non-linear elasticity behavior under the twist angle constraint when the interfacial Helmholtz energy term is incorporating into the scenario. This behavior is in excellent quantitative agreement with the AFM test results obtained by Idiris et al. (2000) on the poly-L-glutamic acid [Glu(n)-Cys] exposed to aqueous solutions, which show that acidity increases the degrees of helicity.

Effects of bathing in different hot spring types on Japanese gut microbiota

Hot springs have been used for a variety of purposes, including the treatment and amelioration of illness and recreation. Japan has ten different types of therapeutic springs (described here as spa types), which are traditionally believed to have different efficacy. However, more research must be conducted to determine how they affect healthy people. Therefore, this study focused on the gut microbiota and aimed to investigate changes in the gut microbiota in healthy people after bathing in different spa types. Using Beppu's hot springs (simple, chloride, bicarbonate, sulfur, and sulfate types), 136 healthy Japanese adults living in the Kyushu area participated in the study and bathed in the same hot spring for seven days. Fecal samples were collected before and after the 7-day bathing period, and the relative abundance of the gut microbiota was determined by 16S rRNA sequencing. The results showed that the relative abundance of Bifidobacterium bifidum increased significantly after seven consecutive days of bathing in the bicarbonate spring. Significant increases in other gut microbiota were also observed after bathing in simple, bicarbonate, and sulfur springs. These results suggest that bathing in different hot springs may affect the gut microbiota in healthy individuals differently.

DESIGN OF VISCO-ELASTIC SUPPORTS FOR TIMOSHENKO CANTILEVER BEAMS

The appropriate design of supports, upon which beams are usually placed as structural components in many engineering scenarios, has substantial significance in terms of both structural efficacy and cost factors. When beams experience various dynamic vibration effects, it is crucial to contemplate appropriate support systems that will effectively adapt to these vibrations. The present work investigates the most suitable support configuration for a cantilever beam, including viscoelastic supports across different vibration modes. Within this particular framework, a cantilever beam is simulated using beam finite elements. The beam is positioned on viscoelastic supports, which are represented by simple springs and damping elements. These supports are then included in the overall structural model. The equation of motion for the beam is first formulated in the temporal domain and then converted to the frequency domain via the use of the Fourier Transform. The basic equations used in the frequency domain are utilized to establish the dynamic characteristics of the beam by means of transfer functions. The determination of the ideal stiffness and damping coefficients of the viscoelastic components is achieved by minimizing the absolute acceleration at the free end of the beam. In order to minimize the objective function associated with acceleration, the nonlinear equations derived from Lagrange multipliers are solved using a gradient-based technique. The governing equations of the approach need partial derivatives with respect to design variables. Consequently, analytical derivative equations are formulated for both the stiffness and damping parameters. The present work introduces a concurrent optimization approach for both stiffness and damping. Passive constraints are established inside the optimization problem to impose restrictions on the lower and higher boundaries of the stiffness and damping coefficients. On the other hand, active constraints are used to ascertain the specific values of the overall stiffness and damping coefficients. The efficacy of the established approach in estimating the ideal spring and damping coefficients of viscoelastic supports and its ability to provide optimal support solutions for various vibration modes have been shown via comparative experiments with prior research.

Nanoscale dynamic mechanical analysis of a viscoelastic matrix inclusion within an elastic substrate

Advanced composite materials incorporate viscoelastic matrix inclusions in designated locations within elastic substrates, which grant them specialized energy dissipation capabilities of dynamic loadings. Identifying the local nanomechanical properties of the matrix-substrate complex within the composite is critical to its design and adaptation toward a specific target function. Here, we conduct FE simulations of nanoscale dynamic mechanical analysis (DMA) testing on hemispherical matrix inclusions within elastic substrates and analyze the variations in its indentation storage loss moduli measures for different matrix-substrate configurations. Then, we describe the mechanical system by simple spring models, identify the dominating parameters at different contact states of the nanoscale DMA testing, and obtain highly accurate analytical formulae that link the indentation measures of the matrix-substrate complex to the individual mechanical properties of the matrix and substrate parts. Our analysis can be directly integrated into benchmark nanomechanical testing methodologies of composite materials and promotes the local dynamic-mechanical characterization of complex materials systems, including nanomaterials, micro-architected structures, and bio-inspired designs.

Removable Orthodontic Treatment for Managing Relapse Due to Eruption of Third Molars: A Case Report

Relapse is a return to the initial form of malocclusion after correction. Relapse occurred after the patient underwent a fixed orthodontic treatment, and it could be associated with the role of third molar eruption. The use of removable orthodontic appliances can maintain the retention period to prevent relapse. This report aims to report the use of removable orthodontic appliances in correcting a minor relapse case. A 23-year-old patient came to RSGM UMY complaining of misaligned upper and lower front teeth for several months after completing fixed orthodontic treatment. She felt her lower front teeth were crowded and moved more backward than the other teeth. The treatment used maxillary and mandibular expansion plates to gain space. The active plate on the maxilla was a medium labial arch and a simple spring on the mandible. A checkup of the patient was seen once a week which involved cleaning the oral cavity and the plate, measuring the space by the activated expansion screw, and checking for correction of individual teeth. The bilateral expansion plate can be used to correct mild anterior crowding due to relapse, followed by an active plate with a simple spring. The success of treatment was influenced by the patient’s cooperation and compliance with using removable orthodontic appliances.

Correction of Central Diastema and Individual Dental Malposition with Removable Orthodontic Appliance

Background: Central diastema refers to an anterior spacing between maxillary central incisors and malposition of the individual teeth refers to the teeth being crowded in the upper and lower jaws. There are many causative factors that contribute to the occurrence of these two cases, such as heredity, frenulum deformity, gender, and bad habit. Removable orthodontic appliances are devices that can be used in cases of mild malocclusion. Objective: The purpose of writing this case report is to show that removable orthodontic appliances are the first choice for dentists. Case: A 23-year-old male patient came to UMY Dental and Oral Hospital (RSGM UMY) complaining that his front teeth had spacing and some irregularly arranged teeth. The patient felt uncomfortable with the condition of the teeth. Patient complaints are felt as early as 3 years ago. One year ago, had already used a removable orthodontic appliance and after the treatment is finished then used a retainer but only for 1 month because the retainer is missing. The case of this patient is class I Angle with central diastema and malposition of individual teeth. Case Management: Treatment is carried out using removable orthodontic appliances. The appliances component uses a simple spring on tooth 31 and 41, retentive component uses Adam’s clasp on teeth 16, 26, 36 and 46. Labial arch with a U loop in between canine and first premolar. Conclusion: The removable orthodontic appliance should be used to correct cases of mild malocclusion such as a central diastema with mild malposition of the individual teeth.

Modelling of thin constrained layer damping treatment applied to composite floor beams

The Vibration Serviceability Limit State (VSLS) due to human dynamic loading is increasingly becoming the sizing criterion for long-span composite floors. To meet this requirement, structural designers usually tend to increase the stiffness or the mass of the floor. This paper studies a damping technology applicable to these floors since the design stage for improving their dynamic behaviour by increasing their damping capacity and avoiding thus over-sizing the floor structure to meet the VSLS. The studied technology is based on a Constrained Layer Damping (CLD) treatment made of a thin viscoelastic (VE) layer integrated between the concrete slab and the steel profile of the floor, along a percentage of the beam length near the supports. Thus, this paper proposes a simplified Finite Element (FE) approach to model this treatment based on using simple SPRING elements for the VE layer and a corrected version of the modal strain energy method for damping estimation, avoiding thus the use of complex modal analysis. The proposed approach is used to assess the additional damping ratio provided by the CLD treatment. The accuracy of this approach has been validated by comparing it with detailed FE models and widely accepted analytical formulations considering different percentages of the beams’ length treated with CLD. Finally, an application example has been performed with CLD-treated and untreated single-spanning composite floors, showing: i) CLD-treated floors have a better dynamic performance, and ii) CLD technology enables reducing the amount of steel needed to design lightweight floors especially sensitive to vibration.

Application of Laplace-based variational iteration method to analyze generalized nonlinear oscillations in physical systems

In this paper, the variational iterative method (VIM) with the Laplace transform is utilized to solve the nonlinear problems of a simple pendulum and mass spring oscillator, which corresponds to the Duffing equation. Finding the Lagrange multiplier (LM) is a significant phase in the VIM, and variational theory is frequently employed for this purpose. This paper demonstrates how the Laplace transform can be utilized to locate the LM in a more efficient manner. The frequency obtained by Laplace-based VIM is the same as that defined in the already existing methods in the literature in order to ensure the clarity of the results. Numerous analytical techniques can be used to solve the Duffing equation, but we are the first to do it using a Laplace-based VIM and a distinctive LM. The fundamental results of my paper are that LM is also the same in the Elzaki transformation. In the vast majority of instances, Laplace-based VIM only requires one iteration to arrive at an answer with high precision and linearization, discretization or intensive computational work is required for this purpose. Comparing analytical results of VIM by Laplace transform to the built-in Simulink command in MATLAB which gives us the surety about the method’s applicability for solving nonlinear problems. Future work on the basic pendulum may examine the effects of nonlinearities and damping on its motion and the application of advanced control mechanisms to regulate its behavior. Future research on mass spring oscillators could examine the system’s response to random or harmonic input. The mass spring oscillator could also be used in vibration isolation to minimize vibrations from one building to another.

Solutions of the Nonlinear Evolution Problems and their Applications

Abstract In this article, a well-known technique, the variational iterative method with the Laplace transform, is used to solve nonlinear evolution problems of a simple pendulum and mass spring oscillator, which represents the duffing equation. In the variational iteration method (VIM), finding the Lagrange multiplier is an important step, and the variational theory is often used for this purpose. This paper shows how the Laplace transform can be used to find the multiplier in a simpler way. This method gives an easy approach for scientists and engineers who deal with a wide range of nonlinear problems. Duffing equation is solved by different analytic methods, but we tackle this for the first time to solve the duffing equation and the nonlinear oscillator by using the Laplace-based VIM. In the majority of cases, Laplace variational iteration method (LVIM) just needs one iteration to attain high accuracy of the answer for linearization anddiscretization, or intensive computational work is needed. The convergence criteria of this method are efficient as compared with the VIM. Comparing the analytical VIM by Laplace transform with MATLAB’s built-in command Simulink that confirms the method’s suitability for solving nonlinear evolution problems will be helpful. In future, we will be able to find the solution of highly nonlinear oscillators.

Structural performance of long-span truss structures in ultrahigh voltage substations under multi-hazard action of earthquake and icing

The transmission line is a vulnerable lifeline system when subjected to extreme loads, such as earthquakes and heavy ice loads. This study numerically investigates the structural performance of ultrahigh voltage long-span truss structures (LSTSs) under the multi-hazard action of earthquake and icing to mitigate disaster losses. A typical LSTS-3-tower-3-line system was selected as an analytical model. Its finite element model was established using a simplified spring model to simulate an ice-covered transmission conductor; it was excited by seven multi-component far-field ground motions. The natural vibration characteristics, structural responses, earthquake failure modes, and bearing capacities of LSTS affected by icing were comprehensively analyzed. The results showed that the seismic response of LSTS decreased, and its total response (induced by the tension of the conductor, ice load, and earthquake) increased with an increase in ice thickness. In addition, icing severely reduced the bearing capacity of LSTS with average reductions of 11.7% and 39.1% when the ice thicknesses were 15 and 50 mm, respectively. Moreover, the influence mechanism of icing on LSTS seismic responses and the failure mechanism of LSTS under the multi-hazard action of earthquake and icing were revealed. Specifically, the failure modes of LSTS, namely flexural (mode 1), mixed (mode 2), and shear failures (mode 3), were determined by the ice condition. Finally, prediction models for the structural responses and bearing capacity of LSTS were developed to facilitate the design of electrical equipment and LSTS and improve design efficiency.

Non-linear Wire Rope Isolator Model to Enhance Transportation Simulation of Fragile Equipment

IntroductionWire rope isolators are often used as means of vibration isolation for the transportation of fragile machine equipment. When deployed as suspension systems in a transportation scenario, a simple spring–damper model is often used to predict the dynamic loads that act on the structure being transported. However, this simple model has proved to be too simplistic to be used in the development of an accurate numerical model that can predict the vibration levels experienced by the inner components of fragile equipment during its transportation. This paper describes the experimental tests conducted on a wire rope isolator used for the transportation of the prototype SSR1 cryomodule.Materials and methodsA hysteretic Bouc–Wen model has been used to analytically describe the force–deformation relationship of the wire rope isolators. The developed model of the isolator has been implemented in a larger model to simulate the actual transportation of the prototype SSR1 cryomodule, a section of the new PIP-II linear accelerator under construction at Fermilab. A series of multibody dynamic simulations with rigid and flexible components was used to numerically determine the acceleration of some critical components.Results and conclusionsAn actual experimental transportation was simulated using two numerical models: the developed Bouc–Wen model and a conventional spring–damper model. It is shown how the Bouc–Wen formulation of the isolator characteristics drastically improves the correspondence between experimental and simulated results if compared to a spring–damper model, especially in the range of 0–30 Hz which is the most critical for transportation problems.

Structural behavior of steel tie connections in masonry veneer walls: Proposal of a simplified approach for practice

Steel ties perform a key structural role in ensuring the stability of buildings façades built with brick masonry veneer walls. These elements are responsible for transferring the loads acting on the veneer wall to the main structure, which typically consists of masonry infill walls used in reinforced concrete frames buildings. Such constructive system is common in Portugal and other Mediterranean countries where the seismic hazard is high. In the event of an earthquake, the ties have to transfer the out-of-plane loads and are subjected to significant tension and compression stress. The characterization of the seismic behavior of these tie connections is an insufficiently explored topic. Despite the codes available for the design of brick masonry veneers and ties, recent earthquakes brought to light the seismic vulnerability of this constructive system. The present paper proposes a simplified spring numerical model validated with experimental results. The simplified model can be applied to perform numerical analyses of greater scale (e.g. to analyze full façades of buildings), which can help to optimize the design. Finally, the paper identifies a common construction problem, which is the probable misalignment of the mortar joints of the masonry walls. A construction solution is proposed by the authors.

3D printable resin/carbon nanotube composites for wearable strain sensors: Enhancing mechanical and electrical properties

Electrically conductive composite materials are widely used for several applications, particularly flexible strain sensors for wearable electronic devices to detect human motions or apply to soft robotic technologies. Among the carbon nanotube (CNT) composites for strain sensors, the CNT composites with polypyrrole (PPy) have been scarcely found for electromechanical property improvement via digital light processing (DLP) 3D printing. Thus, this research presents a 3D printing fabrication of flexible polyurethane/CNT/PPy (FPU/CNT/PPy) composites for high complexity and model specifications, particularly strain sensing. The FPU/CNT/PPy composites were prepared as photopolymer resin with various proportions of the three components. The composites successfully achieved a gauge factor of 91.9 at 20 percent strain with high durability in 100 stretching-releasing cycles. More than 85% of printing accuracy was also found under the DLP 3D printing method. The small deformation of the composites could be detected during the stretching-releasing process during time-dependent testing. Examples of simple human activity and complex spring motion could be successfully detected due to the high responsibility and reproducibility of the finger motion. The composites mentioned in this study could reach the field of strain sensing and can further be applied to other fields such as healthcare and soft robotics.