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The power capture performance of an adaptive bistable point absorber wave energy converter (WEC) in irregular waves is investigated in this paper. Based on the linear potential flow theory and Cummins equations, the equation of motion for the WEC is established in time domain. Then a parametric study is performed on the power capture performance of the WEC by considering the influences of different wave and system parameters such as the spring combination parameter, the stiffness of auxiliary springs and main springs, the original length value of the main spring, damping coefficient of the PTO systems and the significant wave height. The results show that in an irregular wave, each parameter will have a certain impact on the performance of the device. Appropriate device parameters need to be selected according to actual environmental parameters to ensure that the adaptive bistable WEC has better power capture performance than its linear and conventional bistable counterparts.

This experimental study aimed to obtain the actuation properties of Shape Memory Alloy (SMA) spring actuators available under the commercial names of Biometal® NiTiCu and KRL® NiTi NiTiCu, NiTiFe. An objective is to characterize the electro-thermo-mechano-electro behavior of shape memory spring through experimentation via simultaneous measurement techniques. These measurements are synchronized by embedding an impedance analyzer and data acquisition module through a unique program. Moreover, to obtain the mathematical model by parts of the SMA spring and equivalent circuit analysis of active spring through their electro-thermo-mechano-electro characteristics exhibited during shape memory effect. Based on the experimental results, the SMA spring's equivalent circuit is considered a series resistance - inductance​ circuit. It was found from the experimental results that the Biometal® actuator produced more resistance, inductance variation and offered more displacement as compared to KRL® actuators.

Numerical analysis of collision is an important aspect of bridge seismic research. This paper introduces precise integration to the numerical analysis of seismic collision. Firstly, the collision forces of four contact element models were expressed in a unified form, including linear spring model, Kelvin-Voigt model, Hertz model, and Jan-Hertz-Damp model, and then the precision integration formula was derived for solving the collision force. Next, a collision time search method was proposed under the linear acceleration hypothesis, and the seismic collision was divided into a collision phase and a non-collision phase. Different time steps were adopted for the two phases. This strategy was verified by comparing simulation results with the data of theoretical analysis and shaking table test. The results show that precision integration ensures the accuracy of numerical calculation for bridge structure collision under seismic action, and achieves a high calculation efficiency; the contact element model and model parameters should be selected reasonably to analyze seismic collision of bridges; the Jan-Hertz-Damp model of contact elements boasts the highest simulation accuracy among the commonly used models.

A calculation method for workpiece profile variation during double-sided lapping was developed in this study. In this method, shell element in FEM deformation was used to formulate elastic deformation of workpiece, and spring element was used to formulate the contact between workpiece and platens to calculate distribution of their contact pressure considering workpiece elastic deformation. First, the developed method of the contact pressure distribution was evaluated by comparing with a method using a FEM software and the existing methods, and was confirmed to be quite valuable in terms of applicable process and calculation time. Subsequently, the workpiece profile variation was calculated using the developed method for several workpiece conditions, and it was clarified that the uneven workpiece thickness can be modified by the process, but it is difficult to modify the bow shape when the workpiece is not small. Furthermore, the decrease of the load applied to the workpiece was suggested to modify the bow shape of the workpiece.

An automatic protection guard for bikes reduces the impact to the side panels, engine, and the rider's leg when the bike collides with the ground, which follows the reverse quick return mechanism. Include a tilt sensor to monitor the bike's lean angle to activate the system and a wave spring inside the hollow bars to absorb the impact. A tilt sensor will be installed and will set a lean angle to the system. When the bike crosses the calibrated lean angle, the system activates and releases the bars from the system installed onto the bike frame and will take the first contact with the ground surface. To match real-life situations, the time taken for the protection guards to move from initial position to extreme position has been calculated using solid Works motion analysis with an average time taken is 0.14 s, and to find the total deformation different loads and different spring constants have been applied using Ansys software the average deformation is 12 mm. The system helps the rider to ride the bike in a safe mode. The total design system is dynamic and varies with the bike segment but follows the same mechanism.

In the ongoing world, everyone has been using the shock absorber as an essential component in most places like load carriers, large structures, and automobiles. This shock absorber plays a crucial role in the vehicle suspension to absorb the major shocks. So, if we absorb the shocks more efficiently, we can reduce the damage to the vehicle body, passenger and also, we can give a comfortable drive to the driver. In the suspension system, spring is the major part to absorb shocks through spring energy. So, if we use different springs or if we can modify the existing spring with better efficiency then we can increase the shock-absorbing capacity. Based on these ideas, I worked on the comparative analysis between coil spring shock absorber and wave spring shock absorber using stainless steel material under static structural and random vibrational analysis. Through these results, we can understand how effectively the wave spring shock absorber can replace the coil spring absorber in terms of load and deformation. In the end, we can find the effectiveness of springs under different random obstructions using the PSD concept in Ansys. This work can be helpful to mono shock absorber bikes and in other places where springs are required at low space areas. If we replace the coil spring with a wave spring with the same length, we can absorb more vibrations at a more comfortable level for the drivers.

Carbon fiber reinforced epoxy composites are typically difficult to machine due to their anisotropic properties which cause delamination and other damages. Introducing a backup plate beneath the workpiece during drilling has proven to be an efficient and cost-effective strategy to circumvent this problem. With a view to reduce the serious fiber pull-out and delamination problems that occur during conventional drilling of CFRP composites, a novel method of active spring restoring backup force is introduced at the bottom side of the workpiece. The thrust force and delamination are determined experimentally during the drilling of holes at various drilling parameters, with and without back-up force. This spring restoring active backup force technique aids in the continuous hole making process and is found to be a simple, inexpensive and versatile technique to adopt for reducing drilling damages. The applied active backup force contributes in the reduction of delamination even at higher thrust force. The optimal backup force is found to be 321.6 N which results in reduced delamination in drilling of composite laminate.

Traditional oscillating water column (OWC) devices are mostly fixed with almost no components allowed to move. To complement the research of OWC consisting of moving components, the capability in extracting wave energy for a device with a surging front and back lip-wall restricted by different spring stiffness values is investigated. A theoretical model is developed based on potential flow theory and solved by the matched eigenfunction method, and the pros and cons between the proposed model and the traditional fixed model are compared. The influential factors, including the wall drafts and chamber breaths, are explored to study the effects on the interested hydrodynamic parameters. To make full use of the inclusion of surging motion of lip-walls, a progressive optimized process of spring stiffness is proposed to obtain a superior efficiency curve. The results show that a relatively larger lip-wall draft and wider chamber breadth is more beneficial for the improvement of absorption efficiency for the dual-surging-motion model but the peak efficiency remains unchanged. An appropriate combination of the employed two stiffness values can expand the high-efficiency frequency bandwidth, and the peak efficiency can be improved to a better extent in contrast to the traditional fixed device.

Belleville springs are frusto-conical in shape, can support high load with small deflection. Load-Deflection characteristics of a Belleville spring can be altered by stacking of springs. In this research work, Finite Element Analysis (FEA) of Belleville spring was carried out and compared against experimental analysis using strain gauge. FEA was carried out on a plain spring and results were compared with theoretical analysis. Experimental investigation was carried out using strain gauges for different configuration of Belleville springs such as plain spring and spring with stacking. From the studies it was concluded that theoretical, Finite Elemental and Experimental analyses were in good agreement. Spring stacking was done up to 6 numbers, and deflection was significantly altered from 1.46 mm to 8.14 mm (Deflection from one spring to six springs). With the stacking of springs, change in the magnitude of maximum stress was 1.5%. Thus, required load- deflection characteristics can be achieved by stacking of springs when space is not a constraint and large deflection is required.

Sheathed Cold-formed Steel (CFS) wall framed buildings provide various advantages such as speed of construction, environmentally green, high strength-to-weight ratio etc. over construction with conventional materials. In this type of construction, walls are the main load-bearing elements. It has been observed in literature that sheathing significantly influences the load-carrying capacity of CFS wall frame. However, limited studies are available on axial behaviour of calcium silicate board (CSB) sheathed CFS wall panels. Fibre cement board (FCB) sheathed wall panels are proposed in the present study and the same are investigated for their performance under axial loading. A detailed series of experiments on full-scale sheathed perforated CFS single-studed wall panels are carried out and load factors which may be adopted by designers or researchers for evaluating axial strength of sheathed CFS panels, are proposed. Sheathings using FCB and CSB boards are applied on the specimens. Effect of variation of parameters such as type of sheathing, sheathing thickness, layer configuration of sheathing (number of layer on either side) on the load factors are also investigated in the present study. ‘Differential equation of equilibrium’ based analytical method is validated with the experimental results in the present study. In the adopted analytical method, the stud is assumed as channel section restrained by sheathing based springs. The value of spring stiffnesses is obtained analytically as specified in the literature, using modulus of elasticity, obtained through experiments. Suitable modification factor is recommended for panels with sheath on one side, while predicting axial strength of CFS panels with sheath, analytically. The proposed factor may be used with confidence as the experimental results agree well with the analytical results.

In this paper, a novel meshfree approach is proposed for the free vibration analysis of laminated closed conical, cylindrical shells and annular plate with a hole. The theoretical formulation for free vibration analysis is based on the first order shear deformation theory (FSDT) and the field functions are approximated by a Tchebychev-radial point interpolation method (TRIPM) shape function using various radial functions augmented with Tchebychev polynomials as the basis. A laminated closed shell with a hole is decomposed into five open shells without holes, and continuous conditions of displacement are applied at the interfaces between the open shells. The governing equations and boundary conditions for the laminated open shells without hole are derived using Hamilton’s principle. The boundary and continuous conditions are generalized by the introduction of an artificial spring technique, and the type of the conditions is selected according to the spring stiffness values. A comparison with the results of the literatures and finite element software ABAQUS is conducted to verify the accuracy and reliability of the proposed method. The investigation of the vibration characteristics of the laminated closed conical, cylindrical shells and annular plates with a hole according to various radial functions, geometric dimensions and boundary conditions is presented through numerical examples.

The mechanical properties of reinforced concrete (RC) structures are closely related to the bond stress-slip relationship of rebar-concrete interface. In this paper, a novel bond stress-slip model under monotonic and cyclic loading is proposed. For interfacial behaviour under monotonic loading, an innovative micro-element model, consisting of a spring element, a friction element and a switch element, is proposed to effectively characterize the interfacial micro-damage mechanical behaviours in a physical sense. By adopting a parallel system of micro-elements and setting the fracture threshold of individual spring element as a random variable, the expressions of the bond stress-slip relationship and interfacial damage variable are derived. Subsequently, succinct practical expressions for the bond strength, peak slip under monotonic loading are formulated. The bond stress-slip model for rebar-concrete interface under monotonic loading are further established. For cyclic constitutive model of rebar-concrete interface, a new method of cyclic correction factor for the degradation law of bond strength is developed. The bond strength degradation under cyclic loading affected by the number of cycles, maximum slip value and opposite loading can be reflected with reasonable accuracy. Furthermore, the predictions calculated by the proposed model under monotonic and cyclic loading are in favorable agreement with experimental results. All parameters in the model have clear physical meaning.

Recently, many buildings have originally been designed as base-isolated to mitigate the structural vibration. However, buildings with base isolation systems can undergo displacement/amplification demand due to the inherent nonlinear behaviour of the base isolators, especially in earthquake-prone regions. Hence, in some cases it could be necessary to control the seismic response of the base-isolated buildings using supplemental damping device. This paper investigated the effectiveness of nonlinear fluid viscous damper (NFVD) considering design parameters for the base-isolated buildings with lead rubber bearing (LRB). For this, 10-storey benchmark steel moment resisting frame isolated with LRB having a series of isolation periods (T) of 3, 3.5, 4, and 5 s was used. These base-isolated frames consist of three bays and NFVDs having different damping exponents (α) of 0.15, 0.30, 0.50, and 0.70 were inserted in the mid, corner, and all bays of each base-isolated frame at the ground level. The case studied frames were modelled with a finite element program in which LRB elements were characterized by bi-linear hysteretic behaviour while NFVD elements were represented considering the Maxwell model having an elastic spring and a viscous dashpot in series. The nonlinear response of the frames with LRB and NFVD were evaluated by the nonlinear time history analyses using five ground motion records. The analysis of the results were comparatively evaluated considering certain engineering demand parameters such as the storey, bearing, and relative displacements, roof and inter-storey drift ratios, absolute acceleration, base shear, base moment, input energy, and hysteretic curves. One of the main findings of this study is that the base-isolated building with the passive damping device as control attenuation satisfactorily responded when associated with appropriated design parameters.

This paper addresses the determination of the response of beams under static loads, in presence of multiple cracks. The crack is modeled as a rotational internal spring. Both the amplitude and position of the spring are taken as uncertain variables. In particular, its random position characteristic has been modeled as Poisson law distribution along the axial coordinate. By using the theory of generalized functions, the probability transformation method (PTM) has been easily applied to the beam equilibrium equations. The PTM, employing the space transformation laws of random vectors, allows determining the probability density function (PDF) of the system response directly and easily. The results of some numerical applications have confirmed the goodness of the proposed stochastic procedure.

In order to avoid the damage of piezoelectric vibrator due to excessive deformation during resonance, an amplitude-limiting rotational piezoelectric energy harvester excited by a radially dragged magnetic force was presented in this paper. The amplitude-limiting device consisted of two springs and a wedge cam to limit deformation of the piezoelectric vibrator. Simulation analysis and tests were carried out to obtain the influence of system parameters on the response characteristics of the piezoelectric vibrator. The results showed that the amplitude-limiting device could effectively limit the maximal deformation and output voltage of the piezoelectric vibrator. The maximum generated voltage increases with the increases of the wedge cam lift, but the optimum speed range decreases. The effective speed range increased with the decreasing number ratio of exciting magnets and the rising spring stiffness. Moreover, a combination of a high-stiffness return spring and a low-stiffness buffer spring is helpful to enhance the effective speed range and to decrease the fluctuation of output voltage. Therefore, the energy generation capability and bandwidth of the energy harvester could be effectively improved through reasonable parameter matching. Under the load resistance of 40 kΩ, the maximal output power of 2.3424 mW is achieved at the rotating speed of 183.7 rpm.

A vertical spring had a changeable horizontal stiffness to avoid resonance under a seismic displacement, and a viscous damper had a perfect energy dissipation function to reduce the seismic displacement. They were joined together to achieve a seismic isolation system considerably reducing the seismic acceleration response, however, their displacement should be paid more attentions under an earthquake or in a shaking table test. Because the interface friction in the system affected the scaling process of the system in the shaking table test and the corresponding displacement responses, the system was numerically scaled before a real shaking table test. The comparison between the displacement responses of scaled models and prototype models shows that the spatial friction variation and the gravity distortion are the error sources of the relative and residual displacements of scaled models. The error of scaled relative displacement is reduced by the means of increasing PGA, damping constant, spring constant or reducing vertical spring length with zero stress, however, the error of scaled residual displacement is still chaotic under these means. Only if the error sources above are eliminated fundamentally will the error of scaled models be avoided. The conclusions are validated correct by a real shaking table test.

Seismic isolation has been a prevalent approach to seismic design of bridges whereas isolation bearings are susceptible to damages in a major earthquake event. A tie-down cable-spring restrainer (TCR) is therefore proposed to protect isolated bridges under near-fault ground motions. The proposed TCR transmits large horizontal force to the substructure under large earthquakes while does not compromise isolation efficiency of the isolator under small ones. The key concepts and theoretical model are provided in this article and a design procedure is put forward for the application of TCR to a bridge with lead-rubber bearings. Case studies show that seismic isolation and ductile behavior develop sequentially under large earthquakes and the isolators are well protected from excessive displacement. It is found that bridges with TCRs have larger displacement capacity and show less sensitivity to near-fault ground motions.

Accurate modeling of rebound kinematics in particle-substrate collisions is essential in a wide range of applications like milling and mixing. To accurately model these real-world collisions the forces arising due to elastoplastic deformation and friction need to be modelled accurately. In this study the use of frictional boundary conditions in modeling elastic collisions with Smooth Particle Hydrodynamics (SPH) is explored. The collision dynamics for an oblique impact of a 3D spherical granule on an elastic substrate is assessed for SPH (a) without any special treatment for friction and (b) using Coulomb's friction model, and it is identified that these approaches are inaccurate in some instances. To resolve this, spring-based contact models are incorporated in SPH to develop a new method for improved contact modeling. We call this method Collisional SPH. This Collisional SPH method predicts both rebound kinematics and surface deformation accurately. This method opens new avenues for further development in modeling collisional deformations and collision dynamics in granular systems using SPH.

The misalignment and lead crown relief make the tooth partial contact along the tooth width direction, which greatly affects the mesh characteristics. In this paper, a mesh stiffness model of spur gear pairs with misalignment and lead crown relief is proposed based on the slice theory, in which the slice coupling effect is presented. The slice coupling is simulated as a spring and the corresponding model is developed. Then, the solving procedure of the mesh stiffness model is studied. The deformation transfer model is derived between the springs in contact state and non-contact state. An iterative computation method is designed to calculate the mesh deformation of tooth pairs. Finally, the mesh stiffness model is validated by the finite element method for a spur gear pair with ideal tooth profile, misalignment and lead crown relief. Effects of the misalignment and lead crown relief on mesh stiffness of gear pairs are also studied. The results reveal that the proposed model is accurate, effective and efficient for spur gear pairs with ideal tooth profile, misalignment and lead crown relief. It is suggested that the slice coupling should be considered in mesh stiffness calculation of gear pairs with misalignment and lead crown relief.

Leaf spring is a basic type of spring, often used for suspension in wheelchairs. In addition it is probably the most established form of spring, going back to the past. In this worksheet, the spring of CAD depicts the development of a solid edge system and the re production carried out in the ANSYS systems through continuous testing and similar investigations. Spring E-Glass - the mean direction of the spring-blade of the expert leaf at 4000 N is 14.85 mm. The maximum frequency is 548.97 Hz. The reason for the vibration from the recurrence level is therefore significantly comparing to the carbon fiber properties. The avoidance of the avoidance is 13.48 mm which is very low with a recurrence decrease 538.32 Hz. which is also very low and this item can support a lot like traditional spring materials but the thing is good in terms of weight because Carbon fiber does not weigh to him iron 35% weight is reduced by E - Glass materials. This work revolves around the use of polymer composite based leaf spring by additive layer manufacturing using FEA method bases on thermoplastic polyimide with 30% carbon fiber reinforced (composite material) by removing the En 45 metal from the common leaf sources of the suspension system to reduce the weight of the object, improve safety, comfort and durability.

In the preparation of the die cutting process, basic adjustments can be made based on the appearance of the creases and emerging material damage. To achieve an accurate optimization, more elaborate analysis methods are needed. The object of the study was to develop a practical and accurate accessory device for a material tester that combines the advantages of laboratory measuring equipment as well as die cutting tools used in industrial applications. The operation of the developed device and the evaluation method were verified with a series of creasing tests with commercial sample materials. Special attention was paid to crease dimensions, level of spring back, folding resistance and forming force optimization. The changes in the crease material thickness increased as a function of forming depth as expected. The same consistency was not found in the comparison of the depth of the creases formed in different directions. Spring back of the material was deduced to be a significant factor for the final dimensions of creases. In addition, it was discovered the creases do not have to be die cut too fiercely, as the desired functionality can be achieved with less force. Obtained results were considered beneficial in the analysis of materials and in the control of the die cutting process.

A special type of flexure bearings are installed to support a compressor motor and a displacer within a cryocooler which is used in space applications. The fatigue life of spring is a critical factor for such applications, to ensure that the cryocooler does not fail. The flexure spring is used in the setup of an eccentric type of flexure bearing. The present study analyzes various significant parameters and properties in selecting the best suitable material to achieve finite-fatigue life. To avoid a failure of such critical component, batch testing is carried out. The three materials which are compared with respective SN-curve are a] beryllium copper, b] Stainless Steel (3 0 4) and c] Titanium. The study has been carried out to find the best suitable material for flexure bearing. Finite Element Analysis (FEA) is used to understand flexure springs stress and displacement.

In vehicles, problems happen while driving on bumps on road & improper road conditions. The objective of this research is to optimize the performance of the helical coil spring used in the suspension of cars of hatchback segment by varying different parameters of the spring to make it more efficient than the existing coil springs used in current hatchbacks. The helical compression spring utilized in mechanical system or shock may be a machine designed to free or damp shock impulse and dissipate mechanical energy. A helical compression coil spring which is used in four-wheel cars which are belonging in the hatchback category of the Indian automotive market. It is observed that the vehicle drifts towards one side due to the high weight of the suspension system and loads. This problem can be solved by redesigning and optimizing the suspension spring. This project consists of analytical methods and Finite Element Analysis completed from modeling, meshing, and post-processing of front suspension springs to validate calculations. By using Finite Element Analysis (FEA), the structural strength of the coil spring is also evaluated in present work. Based on theoretical and software result comparison is made for the optimum result which meets all requirements which were suggested.

Flexure spring is thin metallic disc used to allow relative motion by bending between the piston and the fixed support in compressor body. The flexure spring deforms by the force applied by piston and come back to its original position. As spiral arms cut from its surface, flexing takes place. The main object of this article is to optimize the spring material to enhance the service life of spring. The present article analyzes five different copper based alloys as these materials are having elasticity property. Initially the model was prepared in Catia software. The Finite Element Analysis (FEA) was carried out by applying boundary conditions. As the total displacement of piston is 10 mm so force is applied at the central hole in such a way that the spring will deform for 5 mm from mean position. Due to applied load stresses will develop in the flexure. The equivalent stress was observed for chosen materials. The equivalent stresses were compared with permissible stress for that material by considering factor of safety (FoS). The cold drawn copper and the Beryllium copper UNS C (TH02) found suitable for flexure spring having the stress within permissible limit. As stiffness is also important property for spring. The deformation was observed in FEA for these two materials by applying 1 N force. The stiffness was calculated. The material was selected which will give maximum stiffness. It was found that the Beryllium copper UNS C (TH02) shows the maximum stiffness.

The behaviour of bridge piers supported on shallow foundations under static and cyclic rotations has been studied through several laboratory tests. A brief review on the observations made by several researchers on the responses of bridge piers on shallow foundation is presented in this paper. During an earthquake, the bridge elements are subjected to horizontal, vertical and rotational movements. In bridge analyses, simulation of bridge elements is done by simple models containing several springs and dashpots, wherein the springs are simulated by corresponding spring constants. Recently, the evolution of performance-based approaches in the design of bridge structures has lead to the incorporation of force–displacement (P-Δ) relationships in bridge design guidelines. The (P-Δ) relationships represent the response of bridge elements under translation movement. The rotational behaviour of bridge elements can be represented by Moment – rotation (M-θ) relationships. The M–θ relationships of bridge piers under rotation have been developed and studied by several researchers. In this paper, a detailed review of several shake table and centrifuge studies conducted to understand and analyse the behaviour of bridge piers supported on shallow foundations has been done in order to identify the various factors controlling the behaviour of shallow footings under static and cyclic rotations.

Role of the primary suspension is very important when the vehicle is taking a turn or railway is negotiating a curve. It is therefore necessary to simulate the behavior of the primary suspension system of the railway using commercially available software to optimize the operating parameters of the suspension such as speed of the railway, curvature etc. In this work, primary suspension systems of the springs are modelled by considering material property variation, load variation and geometrical discontinuities. Both vertical deflections and axial deflection of the springs are considered for the analysis under the action of centrifugal force and gyroscopic couples. Generally, the primary suspension of the railcar is made by Chromium Vanadium (50CrV4) material. On the analysis using this material it was found that the outer wheel primary spring undergo shear failure while taking a turn of radius of curvature 175 m with a speed of 100Kmph. In order to avoid the shear failure, the radius of curvature of the turn should be either 252 m or 292 m. Also, the failure can be avoided by reducing the speed of the train less than 80 kmph at the 175 m turn. Shear stress values at 120 km/hour for chromium vanadium is 1385,4 MPa at 175 m radius, 1108.3 MPa at 252 m radium, 1028.3 MPa at 292 m radius. As the radius increases, less shear stress is observed. For maragaing steel, Shear stress values at 120 km/hour is 1268.48 MPa at 175 m radius, 1001.24 MPa at 252 m radium, 926.61 MPa at 292 m radius. Shear stress values at 120 km/hour for Beryllium copper is 1388.4 MPa at 175 m radius, 1110.5 MPa at 252 m radium, 1030.1 MPa at 292 m radius. The difference of 10–12% is observed between FEM results and analytical results.

Bearings are used to allow the relative motion between the two surfaces. A piston is to slide about the cylinder and shaft has to rotate about its casing. Both requires the relative motion for least frictional losses to be happened. A flexure bearing is a spring which allows relative motion by bending a load element. Flexure bearings have the advantage over most other bearings that they are simple and thus inexpensive. They are also often compact, lightweight, have very low friction, and are easier to repair without specialized equipment. This paper presents design, analysis and manufacturing of flexure bearing for a linear compressor which increases the efficiency of system by achieving maximum stiffness, less stresses and more fatigue life. For this, modelling is done in NX&CATIA and analysis in ANSYS with physical validation of final results by manufacturing actual prototype.

The work involves shock absorber design and analysis for off road vehicles. Off-road race car is light and compact type vehicle so it is difficult to get shock absorber which exactly meet the required specifications. Shock absorbers for off road race car are expensive and difficult to get in local market. This ultimately raises cost of vehicle. Also, imported components do not allow in-house serviceability. The work started with studying the vehicle suspension requirements including performance & durability requirements, various technical parameters and design procedure. After that different component including piston, piston rod, cylinder, spring and orifice of shock absorber are designed using different mathematical formulas and theories. Shock absorber 3D modeling is done using CATIA V5. Then, structural analysis of shock absorber is done using ANSYS by considering three different materials such that: structural steel (ASTM A230), stainless steel (ASTM A313) and alloy steel (ASTM A231). The values of stress and deformation for ASTM A230, ASTM A313 and ASTM A231 are 487.45Mpa, 97.28Mpa & 97.49Mpa and 0.0674 m, 0.01345 m, 0.0129 m respectively. The ASTM A231 material has minimum values of stress and deformation among three materials. Therefore, for ASTM A231 material is selected as spring material. Further analysis is done by changing wire diameter from 10 mm to 7 mm to get optimized performance. The springs are to be designed for higher stresses with small dimensions to have better spring design which leads to save in material and reduction in weight. Therefore, 7 mm diameter is selected for spring. The weight of spring is reduced from 1.551 kg to 0.532 kg due to change in diameter.

The traditional finite element method has the advantages of strong versatility and high calculation accuracy. Thus it is widely applied in various numerical simulation problems. Although the traditional finite element method for solving the shaft-hole assembly problem can obtain better solution accuracy, the process of modeling and calculation take a long time and thus cannot meet the engineering application requirements when the equilibrium position after the assembly needs to be obtained quickly to guide the subsequent process. In this paper, an iterative method based on the spring contact model is proposed. Firstly, the actual form error of the shaft and hole is characterized by the Fourier series expansion method; Then, in the contact surface, we established a discrete spring contact model and obtained the equivalent stiffness of the coupling spring through the discrete solid model. The balance iterative calculation based on the form errors and contact deformation force can finally determine the equilibrium position after the assembly. Compared with the calculation results of the finite element model, the equilibrium position of the shaft-hole assembly can be quickly solved under the condition of sacrificing certain precision. From this aspect it can be estimated that this method has a good potential for engineering application.

Technological advancements are growing at a rapid rate for comforting mankind. Every sector including manufacturing, aerospace, and automobile are growing in terms of technical enhancements, material development and design innovations. An attempt has been made in this investigation to design the spring system used in the suspension system. A suspension system or shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. In a vehicle, it reduces the effect of travelling over the rough ground, leading to improved ride quality, and increase in comfort due to substantially reduced amplitude of disturbances. Hence, the design of spring in suspension system forms the vital designing component. Here, a spring is designed for which material consideration formed the basis of analysis owing to the impact loads the spring experiences during the working cycle. The spring design combines two basic designs i.e. variable pitch and cylindrical designs to amalgamate the advantages and eliminate the drawbacks of individual designs. A 3D model was generated using SolidWorks software which was further imported in another software i.e. ANSYS to analyze various mechanical parameters. A material study was carried out in terms of mechanical properties for the selection of spring material. The selected material were alloy steel (vanadium chrome spring steel) and high carbon steel (music wire spring steel) which is commonly used. The analysis was carried out by varying the applied load on the spring and it was recorded in term of stress and deformation. It can be inferred that the results of analysis showed spring was designed successfully and fulfilled the motives of two basic spring designs in a single combined spring structure. The result was also in accordance to the previous research which showed alloy steel as a promising material for the springs in the suspension system of the vehicle.

Leaf Spring architecture is a major achievement in the design and production of the product in commercial vehicles. The most common designs with a multiplicity of leaves are leaf springs which display hysteresis when loaded and unloaded. The approaches often used to evaluate spring strength are time intensive and expensive, such as resilience tests on the field and rough tests. In the early stage of the design cycle, however, simulated ways to measure strength and rigidity offer useful knowledge and save time and cost. They are versatile for the assessment of various design options and for the early shift in design. In this work, mono leaf spring suspension was analyzed on the fatigue and modal with different composite made by E-Glass and natural fibers and the results are compared with the base materials steel (65Si7). The 3D modelling was carried out and analyzed with ANSYS on both a steel and a composites blade spring.

A fallen depart spring is a fundamental kind of springtime; usually it is most important in the interruption in automobiles. The leaf springs are prolonged and additionally slender sheets related to a framework of teaser enjoyment upper or lower the axle. The single-leaf spring times, or unmarried-leaf springs, it involved to honestly a sheet springtime metal. Those were normally heavy size within center & equal inside a direction of the give up, and they do not typically give an excessive amount of quantity of energy & interruption of lugged motors. The operators are trying the find out to how bigger hundreds usually using the couple of leaf springs; these contain different types of leaf springs of numerous periods advanced in the pinnacle to the particular. A great deal smaller of a fallen leave springtime, in a direction of the lowest it is misting likely to be, presenting it the very same semielliptical kind a solitary fallen go away spring obtains from being thicker inside the center Springs will forestall running from exhaustion due to the duplicated smoothness of spring. A purpose of report is modeling in addition to lay out a leaf spring consistent with the loads carried out. Currently utilized cloth for leaf springtime is solid metal. In this assignment we're going to create fallen leave spring for the goods Mild Steel and additionally composite fabric Glass Carbon by means of the use of various support attitudes. We are misting possibly to look at the toughness variations while converting reinforcement attitude. The calculating of layout is providing Finite Element Analysis Structural Evaluation was finished at leaf springtime through used to specific substances Mild Steel as well as Glass Carbon. Modal in addition to fatigue Evaluation is likewise done.

As an energy source, fuel cells are a good option for distributed generation and implementations for hybrid vehicles. One of the key problems of this technology are its slow internal electrochemical and thermodynamic response, which lead to slow reaction time to transient electrical loads. This article proposes a new configuration and a novel control strategy to solve fuel cell weak transient response by using type 1 AC electric spring (ES-1). Furthermore, it will be shown that the same configuration helps in decreasing the required space for battery storage.

The suspension leaf spring is one of the most crucial parts which help in improving the ride quality of an automobile. It is devised to absorb, store and release the energy. A considerable reduction of unsprung weight is generally adopted to improve comfort and ride quality. A simple but yet effective method to meet this objective is replacing the metallic leaf spring by a composite spring. Other than weight reduction, the composite leaf spring provides additional benefits such as high strength to weight ratio and high elastic strain energy storage capacity. In this research work, a steel mono leaf spring which could be employed in passenger cars is taken as reference, which is further analyzed and compared with composite mono leaf design. The objective of this research work is to investigate the suitability of hybrid composite spring which incorporates carbon fibers and flax fibers as primary and secondary reinforcements respectively. The natural frequency of the composite leaf spring was found to be 93% more than that of steel. Moreover, the incorporation of flax layers in between carbon fibers increased the factor of safety and strain energy owing to its high damping properties.

A deployable M cross section thin-walled boom (M boom) can be flattened and coiled elastically around a hub; and can then be self-deployed by releasing the stored strain energy. The M boom has been proposed as the key member of membrane deployable structures. First, the covariant base vectors of geometrical relation of the single type I tape spring were analyzed by establishing three coordinate systems. Second, the constitutive relation between stress and strain was expressed according to the Kirchhoff-Love hypothesis. Third, the equilibrium and controlling equations of the single tape spring were modeled based on Calladine shell theory. Fourthly, the total strain energy model of the single type I tape spring was built by integration. Fifth, the strain energy of the M boom was modeled by the sum of the strain energies of the six tape springs. Then, the strain energies of the single type II and III tape springs were analyzed. The sum of the strain energies of the six tape springs equals the total strain energy of the M boom. The bending moment model was established based on the minimum potential energy principle. The experimental equipment and four M boom samples were processed. The bending force value of the M booms was tested 20 times. Then, the average peak bending moment was calculated. The relative error between the theoretical and experimental results of the peak bending moment does not exceed 6.5% verifying the accuracy of the theoretical model.

Under extreme working conditions such as high temperature, strong electric and magnetic fields and acidic or basic environments, ceramic springs offer a clear advantage over conventional steel springs. In this study, a tailored grade of silicon nitride ceramic was characterized as spring material. The basic characterization was complemented with component tests. Bend bars, helical springs and conical disk springs were manufactured and tested under various loading scenarios. Manifested by the smallest effective volume of the three tested geometries, helical springs showed the highest fatigue strength. Nevertheless, the complexity involved in manufacturing helical springs pertaining to their geometrical features resulted in a relatively large scatter in fatigue data. The results pointed out the importance of proper design and machining of the contact surface edges in disk springs, which bear the highest stresses. This work demonstrates the potential of producing ceramic springs with broad applicability and sufficient strength and fatigue resistance.

This paper investigates the dynamic behaviors of single- and multi-span functionally graded porous (FGP) beams with flexible boundary constraints modelled by a combination of two-dimensional translational springs and a rotational spring. It is assumed that the pores are distributed either non-uniformly or uniformly according to four porosity distributions and that the material properties vary smoothly along the thickness direction of the beam. The dynamic governing equations are derived from Hamilton's principle within the framework of Timoshenko beam theory and solved by using discrete singular convolution element method (DSCEM) in conjunction with Taylor series expansion (TSE) method. To validate the accuracy of the proposed method, the present results are compared with those in open literature and obtained by finite element method (FEM). A comprehensive parametric study is conducted to investigate the effects of spring constants, boundary condition, porosity distribution, porosity coefficient and beam span ratio on the dynamic behaviors.

Fractional derivative models, which are expressed by combining standard dashpots, fractional dashpots and elastic springs in series or parallel, are often utilized to account for the behaviors for viscoelastic materials. Even with the models extended to finite deformation, the precise definition of objective fractional derivative remains challenging. The proposed fractional derivative model is expressed by the combination of an elastic spring in series with two parallel fractional dashpots. We extend the fractional derivative model to finite deformation through a new approach without defining an objective fractional derivative and assuming the decomposition of the deformation rate into the elastic and inelastic parts. This proposed model can be reduced to the Maxwell model for finite deformation. Such reduction results in a model that stands in between the two existing Maxwell models in which the objective rate of the Cauchy stress is taken as the material corotational rate and the relative corotational rate respectively. The proposed model is applied to the simple shear deformation.

A tape spring can be held tightly coiled on a circular cylinder by means of a tension force applied at the tip. This paper determines the smallest value of the required tension force by means of analytical methods, experiments and detailed numerical simulations. The minimum force depends on the coiling ratio, defined as the ratio between the transverse radius of the tape spring and the radius of the cylinder. It varies with an inverse quadratic relation for coiling ratios smaller than 1 (bending-dominated regime) and with a linear relation for coiling ratios greater than 3.424 (tension-dominated regime). For coiling ratios between 1 and 3.424 there is an intermediate behavior, and the required tension force is non-unique and rather small.

A new model is proposed for the behavior of superelastic shape memory alloy (SMA) helical springs with large index. The derived governing equations consider the response of the spring to monotonic loading followed by complete unloading. In particular, the relation between axial force and axial deformation and the distribution of shear stress in a cross section of the spring wire are determined analytically for the entire loading-unloading cycle. Special attention is given to modeling the unloading stage, for which the proposed solution improves upon existing literature. The model is validated by comparison to 3D finite element simulations and the governing equations are used to investigate the influence of temperature, wire radius and mean radius on the superelastic behavior of a sample SMA spring.

Based on the goal of improving the rock breaking ability when drilling asteroid rock samples under limited energy conditions, this paper proposes a method of drilling rock using self-vibratory drilling head and develops a small self-vibratory drilling head for drilling rock. In order to analyze the dynamic characteristics of drilling rock with self-vibratory drilling head, a rock model hypothesis that the rock consists of a series of micro-segment uniform continuous media is put forward. Base on the hypothesis, the model of drilling rock is constructed, the stability lobes diagram of self-vibratory drilling head drilling basalt is plotted, and the energy mechanism of drilling rock system with self-vibratory drilling head is discussed. The comparison tests of drilling basalt by three kinds of self-vibratory drilling head with different spring stiffness and the conventional method are carried out. The rotational speed is a variable in the comparative tests. The test results show that under the specific rotational speed and spring stiffness, self-excited vibration is produced in self-vibratory drilling head drilling basalt. When self-excited vibration drilling is conducted, although the amplitude fluctuation range of the drilling thrust force is wider than that of conventional drilling, the average drilling thrust force is smaller than the conventional drilling. The amplitude of drilling thrust force increases with an increase in spring stiffness. The method of drilling rock by self-vibratory drilling head is proved to be a potential method for viable drilling of asteroid rock samples.

Tunnel excavations near existing structures impose additional loads on the nearby structures and influence the stress-strain regime of the soils. In the present study, the ground response during the close construction of tunnels and the structural behavior of a segmental lining with an elliptical-shaped cross-section were investigated. The effect of nearby structures and the influence distance for a nearby excavation were discussed in terms of the changes in volume loss around the tunnel, the horizontal soil deformation, and the distribution of internal forces. Furthermore, the structural behavior of the lining was tested by showing the capacity of the reinforced concrete section and by considering the crack development in the elliptical-shaped segment. The results demonstrated that the influence distance of the elliptical-shaped tunnel excavated in coarse-grain soils was approximately four times the minor diameter of the tunnel and that the axial force increased slightly in the part of the lining close to the existing structure when the pillar width was increased. Furthermore, it was demonstrated that crack development is an important issue in tunnels with an elliptical cross-section near the spring line; and therefore, a safe zone corresponding to the onset of several cracks with an allowable width and average crack spacing was recommended.

The article presents the results of semi-elliptic spring stiffness testing. The tests were carried out on a spring mounted in two different methods. One was clamped with U-bolts (similarly as in trucks) and in the case of the other, leaves were fastened together with a central screw. Next, numerical models of both springs were made and the obtained results were compared. An analysis of the results received from the developed calculation model was performed. The relevant conclusions from the studies have been drawn.

For automotive manufacturers, the current scenario is to boost reliability and component performance along with increasing fuel efficiency and the cost of manufacturing. The inquiry is, therefore, being carried out into the use of substitute materials in the development component, increasing the strength-to-weight ratio. The best alternative materials until now were composite materials. This study includes traditional steel helical compression spring and then contrasted with composites used in the development of helical compression spring. The helical compression spring of TATA INDICA VISTA is used for analysis and the helical compression spring load is taken as 4544.3 N. The composite material is EGlass/Epoxy and Carbon/Epoxy. In modeling the helical compression spring, solid works 2013 are used and commercial Ansys 14.5 is used for static and modal analysis. The study shows that the natural frequency produced in the helical compression spring of the composite material is reduced in transverse mode, but increases in both compression and torsional mode.

This paper takes the effect of the semi-rigid joints into account to optimise the assembled free-form single-layer grid structure. Based on the experimental results of the semi-rigid joints, finite element models of single-layer grid structure with semi-rigid joints are established, and virtual spring elements are used to simulate the joint stiffness. The optimisation process is completed with the parallel collaboration of ANSYS and MATLAB data. The research goal is to minimise the total strain energy. Genetic algorithm is used for the optimisation, and the nodal z-coordinates are chosen as variables. The effect of the semi-rigid joints on the shape optimisation is studied by changing the joint stiffness. With this method, the optimal shapes of assembled grid structure with different joint stiffness and improved buckling load are obtained.

In this study, the effects of contact force modeling parameters, which included the particle–particle friction coefficient (A), spring constant (B), ratio of the tangential spring constant to normal spring constant (C), normal restitution coefficient (D), and tangential restitution coefficient (E) presenting in the linear spring-dashpot contact model on the hydrodynamics profile of spouted bed reactor, were investigated via computational fluid dynamics coupled with discrete element method (CFD-DEM) using Multiphase Flow with Interphase eXchange (MFIX). First, the base case simulation was validated with the experimental data. Next, the 2k factorial experimental design and an analysis of variance (ANOVA) were conducted to identify the significant main and interaction contact force modeling parameters. Four response variables were observed: the translation kinetic energy of particles, the rotational kinetic energy of particles, the bed expansion, and the standard deviation of pressure drop. Based on these results, the particle–particle friction coefficient, spring constant, and normal restitution coefficient were the major contact force modeling parameters that affected the system hydrodynamics in the spouted bed system. In addition, the effects of main and interaction contact force modeling parameters were summarized, which enhanced our knowledge of the modeling parameters on system hydrodynamics. Contact force modeling parameters must be carefully selected when simulating the spouted bed reactor or related gas-solid multiphase flow process, such as fluidized bed reactor.

In this work, the experimental study was conducted on fractured helical coil spring of a passenger car. The fracture occurred in ASTM A401 helical coil spring at the 2nd active coil, 20.24 mm from the bearing coil. A fitting Lorentz method was used to obtain the most intense peaks, which was placed at 0° and 35° X-ray incidence angles. Further, X-ray tri-axial stresses were obtained from conventional X-ray diffraction method for coil spring under consideration. The present method followed 2-D X-ray diffraction “ cos α ” method. FWHM of the spring was also investigated and validated with conventional X-ray diffraction method.

Dynamic fracture effects such as fracture delay and dependence of the material strength on the loading rate are known from multiple experiments on crack initiation and spallation. Classic linear oscillator (mass-spring system) is considered and critical spring stretch fracture condition is added. Due to relative simplicity of the model and availability of analytical solutions, the dynamic fracture effects can be studied analytically for the case of dynamic loading. Moreover, the mass-spring model can be calibrated to simulate some known experimental results on dynamic crack initiation due to pulse loading.

The dynamic characteristic of interfacial debonded Ferry Ro-Ro’s stern ramp/door is studied by using finite element software ABAQUS. The effect of debonding on vibration responses of damaged stern ramp/doors is assessed by comparing numerical parameters of natural frequency shifts between intact and damaged models. Parametric studies over a wide range of debonding shapes to explore the influence of this parameter on the overall dynamic behavior of the models are investigated. Boundary conditions describing the loading conditions of the ship are evaluated. Four different debonding shapes with a similar debonding ratio, such as circular, square, through-the-length, and through-the-width, are investigated. To evaluate the effect of modeling techniques, both debonding shapes with and without spring contact element models are examined. Consequently, natural frequencies shift is being determined as functions of these parameters that enable to conclude the influence of debonding. The result has been shown that the debonding defect reduced the natural frequencies, especially in the square and circular debonding shapes. There is no significant frequency shift in the through-the-length, and through-the-width debonding modeling. Neglecting of contact leads to incorrect results, which significantly overestimate the value of natural frequency, so the spring contact modeling is recommended. The higher natural frequencies are found to be more sensitive to the presence of debonding problems. Using natural frequency shifts directly resulting from both intact and debonded models, the diagnostic can be performed.