The purpose of this study is to investigate the behavior of the sliver pick-up from can in gill-box machines during feeding process. A model is presented to predict the height changes of can plate during the feeding process. To this aim, a mass-spring model is introduced. The behavior of the can plate is considered as linear spring system and the sliver weight in the can is also noted as time depended mass value. The mass spring derived equations are solved using Three-order Straight Forward Expansion method. Result of can plate height predicting by the model is compared to some experimental data which are collected from a wool yarn mill. The meaningful 12 percent difference between proposed model and the experimental value proves the acceptable result of desired model that can be used for predicting the height of can plate by the aim of machine speed and sliver count.

The main cause of oscillation during the movement of the vehicle is the unevenness of the road. Therefore, in order to maintain the stability of the car in swing states, the suspension system plays an essential role. Therefore, the active suspension system is used to replace the conventional passive suspension system, to improve comfort and smoothness. To reduce the displacement of the spring mass in the active vehicle suspension system, a high-order sliding mode controller is proposed in this paper. Uncertainty of system parameters, nonlinear characteristic of damping and spring, load changes and unknown path disturbance are estimated by disturbance observer. The controller only needs the information of the spring mass state variables and therefore does not need separate sensors to measure the suspension mass state variables. Particle swarm optimization algorithm has been used to determine the control parameters. The efficiency of the proposed method has been shown using simulation in MATLAB software and the results have been compared with the passive suspension system.

This study is concentrated on the natural frequencies and mode shapes of a simple three-member space frame coupled with a dynamic vibration absorber. The dynamic vibration absorber is modeled as a sixdegree-of-freedom mass-spring system. For the first time, the free vibration of an elastic structure with a six-degree-of-freedom mass-spring system is found. Each member of the space frame has uniform mechanical and geometrical properties, but these may differ from one member to another. The exact result of this complex problem is obtained via analytical scheme and finite element method. All effects of the axial and torsional deformations and also in-and out-of-plane bending are taken into account. This formulation includes eighteen differential equations along with thirty six boundary and compatibility conditions. Comparison of the results by both approaches mentioned above, illustrates the accuracy of our solutions. Findings are useful benchmarks for the natural frequencies and mode shapes of the space frame coupled with a dynamic vibration absorber.

In this study, an impact behavior of spherical striker on a double-walled carbon nanotube (DWCNT) is presented based on a three degree of freedom spring-mass model and the finite element (FE) simulations. The semi-analytical solution of the transverse impact of a striker on a DWCNT is investigated by using the elasticity nonlocal theory of Euler-Bernoulli (EBT) and Timoshenko (TBT) nanobeams. The spring-mass system with spring constant is used that involves shear and bending deformation. The van der Waals (vdW) interaction between two layers of a DWCNT is included in the analytical model. The results of this analysis are compared with the results of the FE simulation. The results from the spring-mass model demonstrated good agreement with FE simulation for various values of a DWCNT dimension, chirality, boundary condition, number of layered and also striker parameters such as mass and velocity. The DWCNT independent of vdW interaction is more flexible than DWCNT with vdW forces.

The main objective of this article is evaluation of the simplified models which have been developed for analysis and design of liquid storage tanks. The empirical formulas of these models for predicting Maximum Sloshing Wave Height (MSWH) are obtained from mass spring Models (MSM). A Finite Element Modeling (FEM) tool is used for investigating the behavior the some selected liquid storage tanks under available earthquake excitations. First, the results of FEM tool are verified by analyzing a liquid storage tank for which theoretical solution and experimental measurements are readily available. Then, numerical investigations are performed on three vertical, cylindrical tanks with different ratios of Height to Radius (H/R=2.6, 1.0 and 0.3). The behaviors of the tanks are initially evaluated using modal under some available earthquake excitations with various vibration frequency characteristics. The FEM results of modal analysis, in terms of natural periods of sloshing and impulsive modes period, are compared with those obtained from the simplified MSM formulas. Using the time history of utilized earthquake excitations, the results of response-history FEM analysis (including base shear force, global overturning moment and maximum wave height) are compared with those calculated using simplified MSM formulations. For most of the cases, the MSWH results computed from the time history FEM analysis demonstrate good agreements with the simplified MSM. However, the simplified MSM doesn’t always provide accurate results for conventionally constructed tanks. In some cases, up to 30%, 35% and 70% average differences between the results of FEM and corresponding MSM are calculated for the base shear force, overturning moment and MSWH, respectively.