Explore the vast range of titles available.

Some complex engineering structures can be modeled as multiple beams connected through coupling elements. When the coupling element is elastic, it can be simplified as a mass-spring system. The existing studies mainly concentrated on the double-beam coupled through elastic connectors, where the connector is simplified as the equivalent linear stiffness element or linear mass-spring system. Furthermore, many researches ignore rotational boundary restraints in analyzing dynamic behavior of the double-beam connected through elastic connectors, limiting their engineering generality. Considering the above limitations, this study attempts to employ the cubic nonlinear stiffness in the coupling mass-spring system and study the potential application of the mass-spring system that is nonlinear on the vibration control of the double-beam system. Using the variational method and the generalized Hamiltonian method build the corresponding system’s governing functions. Applying the Galerkin truncation method (GTM) obtains the dynamic behavior of the double-beam connected through a mass-spring system that is nonlinear. According to this study, the change of the mass-spring system that is nonlinear significantly influences the dynamic behavior of the double-beam system, where the complex dynamic behavior occurs under certain parameters of the mass-spring system that is nonlinear. Suitable parameters of the mass-spring system that is nonlinear are good at the vibration suppression at the boundary of the vibration system. Furthermore, the mass-spring system that is nonlinear can change the characteristics of the double-beam system’s kinetic energy transfer. For the vibration model established in this work, a quasi-periodic vibration state can be regarded as a sign of the occurrence of the targeted energy transfer of the double-beam connected through a mass-spring system that is nonlinear.

Mass-spring systems (MSS) simulating elastic materials obey constraints known in elasticity as the Cauchy relations , restricting the Poisson ratio of isotropic systems to be exactly ν = 1 / 4 . We remind that this limitation is intrinsic to centrosymmetric spring systems (where each node is a center of symmetry), forbidding them for instance to simulate incompressible materials (with ν = 1 / 2 ). To overcome this restriction, we propose to supplement the spring deformation energy with an energy depending on the volume only, insensitive to change of shape, permitting MSS to simulate any real isotropic materials. In addition, the freedom in choosing the spring constants realizing a given elastic behavior allows to manage instabilities. The proposed hybrid model is evaluated by comparing its response to various deformation geometries with analytical model and/or finite element model. The results show that the hybrid MSS model allows to simulate any compressible isotropic elastic material and in particular the nearly incompressible (Poisson ratio ν ≃ 1 / 2 ) biological soft tissues to which it is dedicated.

The prosthetic socket provides the critical interface between the prosthetic device and the patient’s residual limb. Since each stump is unique in terms of morphology and mechanics, each socket should be patient specific. Computer-aided design solutions have been proposed in the literature. However, there is a lack of an efficient solution able to modify local information based on soft tissue deformation feedback to enhance the design process. The objective of the present work was to develop and evaluate a computer-aided design approach with real-time soft tissue deformation feedback and an inverse approach to optimize the stump–socket interaction. A computer-aided parametric socket design workflow was proposed. Soft tissue deformation was performed using a novel formulation of the mass-spring system. An inverse approach was proposed to estimate and optimize the stump–socket interaction. An interactive parametric design tool was also developed and evaluated. The proposed approach was applied on a CT-based dataset. Finally, the obtained design outcomes were compared with FE simulation outcomes for evaluation purpose. As results, a virtual socket prototype of the CT-based stump model was designed and illustrated by an interactive process. The comparison of stump–socket interaction behavior with FE simulation outcomes showed a very good agreement with a pressure absolute deviation error ranging from 1.44 ± 2.13 to 3.66 ± 4.56 kPa. Moreover, the contact pressures are below the pain-threshold curves, confirming the comfortability of the designed sockets according to the predefined criteria. The present study proposed a computer-aided socket design solution to locally enhance the socket geometry and mechanics. This opens new avenues to increase the design accuracy, reduce the design cost and give the involved patient a geometrically and mechanically fitted socket device. As perspectives, this process will be integrated with our available visual sensor fusion toward a complete computer-aided socket design system for lower limb prosthetic design and fabrication.

An analytical technique has been developed based on the harmonic balance method to obtain approximate angular frequencies. This technique also offers the periodic solutions to the nonlinear free vibration of a conservative, couple-mass-spring system having linear and nonlinear stiffnesses with cubic nonlinearity. Two real-world cases of these systems are analysed and introduced. After applying the harmonic balance method, a set of complicated higher-order nonlinear algebraic equations are obtained. Analytical investigation of the complicated higher-order nonlinear algebraic equations is cumbersome, especially in the case when the vibration amplitude of the oscillation is large. The proposed technique overcomes this limitation to utilize the iterative method based on the homotopy perturbation method. This produces desired results for small as well as large values of vibration amplitude of the oscillation. In addition, a suitable truncation principle has been used in which the solution achieves better results than existing solutions. Comparing with published results and the exact ones, the approximated angular frequencies and corresponding periodic solutions show excellent agreement. This proposed technique provides results of high accuracy and a simple solution procedure. It could be widely applicable to other nonlinear oscillatory problems arising in science and engineering.

Mass Spring Systems (MSS) are often used to simulate the behavior of deformable objects, for example in computer graphics (modeling clothes for virtual characters) or in medicine (surgical simulators that facilitate the planning of surgical operations) due to their simplicity and speed of calculation. This paper presents a new, two-parameter method (TP MSS) of determining the values of spring coefficients for this model. This approach can be distinguished by a constant parameter which is calculated once at the beginning of the simulation, and a variable parameter that must be updated at each simulation step. The value of this variable parameter depends on the shape changes of the elements forming the mesh of the simulated object. The considered mesh is built of elements in the shape of acute-angled triangles. The results obtained using the new model were compared to FEM simulations and the Van Gelder model. The simulation results for the new model were also compared with the results of the bubble inflation test.

In the aviation industry, ensuring both the structural integrity and passenger comfort of aircraft stands as a primary concern, driven by the potential hazards posed by fatigue failures in structural components. This study endeavours to undertake a comparative examination of various damping coefficients and spring constants within a typical landing gear system. These parameters are then integrated with a Proportional-Integral-Derivative (PID) controller to elevate the performance standards of the landing gear control system. The overarching objectives include the reduction of peak overshoot and the minimization of settling time concerning aircraft displacement, thereby amplifying overall safety measures and passenger comfort levels. The landing gear system under investigation is delineated through a sophisticated (2 DOF) Mass-Spring-Damper model, which furnishes the foundation for deriving the equation of motion. Leveraging the specific parameters of the aircraft, alongside the derived equations, a meticulously crafted MATLAB/Simulink model is established, facilitating comprehensive analysis and simulation procedures. By applying Laplace transform methodologies, a transfer function is meticulously constructed. This facilitates the seamless integration of a PID controller with the system, thereby laying the groundwork for establishing a closed-loop control system. Such a system affords precise regulation and optimization of the landing gear dynamics, culminating in enhanced operational efficacy. A rigorous comparative analysis is conducted to gauge the efficacy of various models, prompting adjustments to the spring constants and damping coefficients based on the discerned findings. This iterative refinement process serves to fine-tune and optimize the system's performance in alignment with the predefined objectives.

The detrimental effects of low-frequency vibrations on the measurement accuracy of commercial high-precision instrumentation demand urgent resolution, particularly for instruments requiring <1 μm positioning stability. Conventional base-mounted active damping systems exhibit limitations in suppressing the structural resonance induced by passive isolators—especially when the environmental vibration intensity surpasses the standard thresholds. Therefore, in this study, we developed an innovative multi-mode control architecture to substantially enhance the vibration-damping capabilities of the DCSMS. The proposed methodology synergistically integrates foundation vibration isolators with embedded passive modules through a dual-stage spring-mass system optimization framework. Experimental validation combining ADAMS–MATLAB multi-physics co-simulation, complemented by a decoupling analytical control model based on the vibrational transmission characteristics of the source propagation path, substantiated the efficacy of the proposed control methodology.

This paper investigates the nonlinear dynamic response of a single-degree-of-freedom mass-spring system. The experimental modal analysis is carried out by three typical types of spectral testing which are burst random, sine testing and periodic chirp excitation to achieve the objective of this study. The experimental data from the burst random excitation is used to identify the natural frequency of the system. The nonlinear dynamic response of the system is detected by means of using the sine testing and periodic chirp excitation. However, from the sine testing, the results showed that the variations of the maximum peak of the vibration acceleration based on the different levels of excitation voltage that were applied to the input shaker. It was also found that the displacement values obtained from the periodic chirp excitation showed an inconsistent linear increment with the excitation level that applied to the mass-spring system.

In a 3D simulation, numerous physically and numerically related calculations are required to represent an object realistically. The existing CPU (central processing unit) technology, however, is incapable of handling such a large computational amount in real time. With the recent hardware-technology advancements, the GPU (graphics processing unit) can be used not only for conventional rendering operations, but also for general-purpose computational functions. In this paper, a mass-spring system for which the CPU and GPU versions are tested under the PC and mobile environments wherein the GPGPU (general-purpose computing on GPUs) is applied is proposed. For this paper, a virtual cloth with a mass-spring system was freely dropped onto a table, and the CPU and GPU performances were compared. The computational GPU performances regarding the PC and mobile devices were improved by 9.41 times and 45.11 times, respectively, compared with the CPU. The proposed GPU mass-spring system was then implemented with an edge-centric algorithm and a node-centric algorithm. The edge-centric algorithm is divided into two parts as follows: one for the spring-force calculation and one for the node-position calculation. These two parts are combined into a single computational process for the node-centric algorithm. For this paper, the computational speeds of the two algorithms were measured. The node-centric algorithm is faster than the edge-centric algorithm under the PC environment, but the edge-centric algorithm is faster under the mobile environment.

This article studies the entropy generation of a mass-spring-damper mechanical system, under the conformable fractional operator definition. We perform several simulations by varying the fractional order γ and the damping ratio ζ , including the usual dynamic response when γ = 1.0 and the typical damping cases. We analyze the entropy production for this system and its strong dependency on both γ and ζ parameters. Therefore, we determine their optimal values to obtain the highest efficiency of the MSD response, as well as other impressive features.