Wyniki wyszukiwania - BazTech

1

Prediction of Compression Properties of Single Jersey Weft-knitted Fabric by Finite Element Analysis Based on the Hyperfoam Material Model

Soltanzadeh Z., Shaikhzadeh N. S., Haghpanahi M., Mohajeri-Tehrani M. R.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 2 (116)

82--88

EN

A 3-D finite element model based on the hyperfoam material model was developed in order to predict the compression behaviour of knitted fabrics in a large deformation state. The degree of compressibility of the fabric is determined by the extent of its volume reduction under external pressure. The compression properties of nine produced knitted fabrics at eight pressure values (2.04, 5.10, 10.19, 20.39, 50.97, 101.94, 152.90, and 203.87 kPa) were measured using a fabric thickness tester and results were compared with finite element results. The FEM results of fabric thickness changes (∆T) and fabric compressibility (EMC) showed good agreement with experimental results, with an average error of 5 and 4.9 percent, respectively. However, the results of fabric linearity of the compression (LC) and work of compression (WC) showed fair agreement, with an average error of 24.5 and 24 percent, respectively.

PL

Publikacja dotyczy analizy kompresji dzianin lewo-prawych o trzech wariantach splotów. Scharakteryzowano parametry dzianin, tj. ścisłości rządkowe i kolumienkowe, masy, zapis splotu w rzeczywistym przebiegu i na igłach. Wykonano badania eksperymentalne i teoretyczne procesu ściskania dzianin wraz z analizą porównawczą. Badania teoretyczne przeprowadzono w ramach eksperymentu numerycznego w środowisku programu ABAQUS. Uzyskane wyniki badań posłużą w projektowaniu właściwości fizycznych wyrobów skarpetkowych przeznaczonych dla diabetyków.

2

Payload Maximization for Mobile Flexible Manipulators in Environment with an Obstacle

Heidari H., Haghpanahi M., Korayem M. H.

Journal of Theoretical and Applied Mechanics

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2015

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Vol. 53 nr 4

911—923

EN

A mobile flexible manipulator is developed in order to achieve high performance requirements such as high-speed operation, increased high payload to mass ratio, less weight, and safer operation due to reduced inertia. Hence, this paper presents a method for finding the Maximum Allowable Dynamic Load (MADL) of geometrically nonlinear flexible link mobile manipulators. The full dynamic model of a wheeled mobile base and the mounted flexible manipulator is considered with respect to dynamics of non-holonomic constraint in environment including an obstacle. In dynamical analysis, an efficient model is employed to describe the treatment of a flexible structure in which both the geometric elastic nonlinearity and the foreshortening effects are considered. Then, a path planning algorithm is developed to find the maximum payload that the optimal strategy is based on the indirect solution to the open-loop optimal control problem. In order to verify the effectiveness of the presented algorithm, several simulation studies are carried out for finding the optimal path between two points in the presence of obstacles. The results clearly show the effect of flexibility and the proposed approach on mobile flexible manipulators.

3

Analysis of different material theories used in a FE model of a lumbar segment motion

Gohari E., Nikkhoo M., Haghpanahi M., Parnianpour M.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 2

33--41

EN

In this study, a nonlinear poroelastic model of intervertebral disc as an infrastructure was developed. Moreover, a new element was defined consisting a disc (Viscoelastic Euler Beam Element) and a vertebra (Rigid Link) as a unit element. Using the new element, three different viscoelastic finite element models were prepared for lumbar motion segment (L4/L5). Prolonged loading (short-term and longterm creep) and cyclic loading were applied to the models and the results were compared with results of in vivo tests. Simplification of the models by using the new element leads to reduction of the runtime of the models in dynamic analyses to few minutes without losing the accuracy in the results.