Engineering Mechanics

Proceedings Vol. 10 (2004)

ENGINEERING MECHANICS 2004

Copyright © 2004 Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Prague

 

Čulík J., Mařík I.
pages 65 - +8p., full text

The children scoliosis can be treated by a corrective brace. The computer program of a spine stress state and spinal deformation under the brace effects was composed and verified by real scoliosis treatment course. The brace is worked in this way: the first is made a negative and then the positive plaster form of the child trunk. The orthotic according to his and orthopaedist experiences deeps the plaster positive form at the places where the brace has to push on the child trunk. The plastic form is then made according to this plaster form. The computer algorithm of stress state calculation is based on the finite element method. The spine is considered as stiff at the vertebrae and elastic at the inter-vertebrae discs. The spine is solved as beam on an elastic base – the soft tissue of the trunk. It is determined the stiffness matrix of spine elements (spinal element is from the vertebra centre to neighbour vertebra centre) and the potential energy of elastic base influence. The trunk surface displacement is given by brace form and the prescribed displacements are used as system load. The brace pushes on soft tissue of trunk as small shoe principle. The computer program uses two algorithms: the first one has as input trunk surface displacements and as output spine stress and deformation state, the second algorithm has as input the spine deformation, measured as a difference between the X-rays of spine without and with brace and as the outputs and need trunk surface displacements as load influence. The second algorithm is better for clinic praxis. If the brace is applied for a long time the part spine deformation is corrected. The computer simulation of spine curvature remodelling is to of second part of article.

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