Wyniki wyszukiwania - BazTech

1

A 4-link model of a human for simulating a forward fall

Grzelczyk D., Biesiacki P., Mrozowski J., Awrejcewicz J.

Vibrations in Physical Systems

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2018

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Vol. 29

art. no. 2018008

EN

In this paper we consider a 4-link model of a human for simulating a forward fall. The model implemented in Mathematica is constructed based on a planar mechanical system with a non-linear impact law modelling the wrist-ground contact. The segments of the human body are modelled as bodies connected by rotary elements which correspond to the human joints. Parameters and kinematic relations used in numerical analysis are obtained based on the 3D scanned model of the human body created in Inventor and experimental observation by the motion capture system. Validation of the model is conducted by means of comparing the simulation of the impact force with the experimental data obtained from the force platform. The obtained ground reaction forces can be useful for the finite element analysis of the numerical model of the human upper extremity.

2

Dynamic simulation of a novel “broomstick” human forward fall model and finite element analysis of the radius under the impact force during fall

Grzelczyk D., Biesiacki P., Mrozowski J., Awrejcewicz J.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 1

239--253

EN

The paper presents dynamic simulation and experimental identification of a human forward fall model describing the process of “falling like a broomstick” on the outstretched arms. The model implemented in Mathematica allows one to estimate time histories of the ground reaction force in different scenarios of the fall process. These time series are applied as time-varying load conditions to the numerical analysis of the human radial bone model created from the computed tomography data. Finally, the obtained numerical results indicate that the strain criterion seems to be more useful for estimating the radius fracture site in comparison to the stress criterion.

3

Związki gęstości prześwietleniowej oraz zawartości składników mineralnych w ludzkiej kości beleczkowej z jej wytrzymałością

Mazurkiewicz A.

Acta Mechanica et Automatica

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2009

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Vol. 3, no. 3

39-42

PL

W pracy przedstawiono wyniki badań związków gęstości prześwietleniowej oraz zawartości składników mineralnych w ludzkiej kości beleczkowej z jej wytrzymałością. Dokonano oceny stopnia zgodności szacowania wytrzymałości kości na podstawie pomiaru gęstości prześwietleniowej kości, w porównaniu z szacowaniem wytrzymałości na podstawie zawartości składników mineralnych w kości.

EN

In the paper, it was presented results of investigation relations between DEXA density, mineral content and strength of human trabecular bone. An agreement of evaluation strength of trabecular bone on the base DEXA density and mineral content of trabecular bone was proved.

4

Monitoring Techniques of Bone Fracture Healing Using External Fixators

Jasińska-Choromańska D., Sadzyński I.

Engineering Transactions

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2003

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Vol. 51, iss.2-3

255-265

EN

Long bone fractures can be healed using external fixators - devices that stiffly fix the fractured fragments, attached to the bone by pins parallel to the bone frame. This method enables to benefit both from healing and diagnostics of fracture during osteogenesis. Osteogenesis, traditionally diagnosed using X-rays methods (RTG, densitometry), can also be more precisely determined with mechanical properties like strength and stiffness inside the fracture slot. The treatment of long bone fractures by external fixators offers a unique opportunity to control the healing of the fracture by measuring the compression forces on the frame, that occurs under the load applied to the bone and depends on the mechanical properties of the fracture. The procedure of measurement of the compression force on the frame can be performed using tensometers, what is a cheap and simple method, and can be performed by the patient at home. The measurement of osteogenesis gives a possibility of more precise diagnostics of the fracture. It can also be combined with computer techniques like artificial intelligence. The paper presents one of the methods of monitoring the bone fracture healing.

5

Fabric tensors in bone mechanics

Jemioło S., Telega J. J.

Engineering Transactions

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1998

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Vol. 46, iss. 1

3-26

EN

Mechanical properties of cancellous and cortical bone have been investigated. The fabric tensors used in the relevant literature have been discussed. Nonlinear elastic and elastic-perfectly plastic constitutive relationships have been proposed within the framework of small deformations. To this end the theory of representation of tensor functions has been used. It has beenshown that the fabric tensor plays the role of a parametric tensor. Orthotropic linear elasticity has been carefully examined from the point of view of interrelations of classical material constants with the proposed material parameters and eigenvalues of the fabric tensor. Hoffman's strength criterion has been extended by incorporating the fabric tensor. Anisotropic properties of human cancellous and cortical bones have been investigated by using the relations derived.