Contents of Journal of Mechanical Engineering 53, 2 (2002)


A. JOHN: Boundary conditions and yield criteria in numerical analysis of human pelvic bone 65 M. CHMURAWA, A. JOHN: Numerical analysis of forces, stress and strain in planetary wheel of cycloidal gear using FEM 77 A. J. NOWAK, R. A. BIALECKI, A. FIC, G. WECEL: Numerical solution of coupled conduction-convection-radiation heat transfer problem in a continuous casting process 92 J. JANKOWSKI: Applications of the method of Fictitious Heat Sources to engineering heat conduction problems 109 M. SZENTPETERI, M. ZIGO: Measuring and computing of inertial properties of human body (in Slovak) 123


Abstracts



Boundary conditions and yield criteria in numerical analysis of human pelvic bone

ANTONI JOHN

Numerical modeling of the human pelvic bone makes it possible to determine the stress and strain distribution in bone tissue. Some simplifications of the numerical model are performed. The stress distribution depends on boundary conditions and yield criteria. In the paper maximum shear-stress (Tresca) criterion, shear-strain energy (von Mises) criterion and Burzynski's criterion are applied and some examples of boundary conditions are presented. The shell and solid model of the pelvic bone are analyzed using the finite element method. Some numerical results are presented.


Numerical analysis of forces, stress and strain in planetary wheel of cycloidal gear using FEM

MANFRED CHMURAWA, ANTONI JOHN

The complex construction of planet wheels in cycloidal planetary gear (Cyclo) practically makes impossible its optimal design. To calculate distribution of forces, strains and stresses in planet wheels with co-operating elements, FEM has been implemented. Series of numerical models of planet wheels were generated to simulate a real gear, and proper values of forces, strains and stresses were calculated. In the paper forces and strains calculated with FEM have been used to check assumptions applied only in analytical calculations, so far. Analysis of displacements enabling to identify constraints in the contact area between cooperating elements of Cyclo gear were not performed up to now.


Numerical solution of coupled conduction-convection-radiation heat transfer problem in a continuous casting process

ANDRZEJ J. NOWAK, RYSZARD A. BIALECKI, ADAM FIC, GABRIEL WECEL

In this paper the enthalpy formulation is applied to analyse a conjugate conduction-convection-radiation problem resulting from the Czochralski crystal growth process which can also be considered as a steady-state continuous solidification of a semitransparent medium. The solidifying material is treated as a pure substance with material properties dependent neither on temperature nor wavelength.

Solution of the problem is obtained iteratively using two computer codes: Fluent a commercial CFD package and BEM based in-house code capable of analysing the radiative heat transfer in the entire computational domain. Numerical algorithms for calculation of the temperature field are presented with emphasis on coupling of the thermal radiation with other modes of heat transfer. Results obtained show also the influence of thermal radiation on the velocity field in the liquid phase as well as on the resulting temperatures.


Applications of the method of Fictitious Heat Sources to engineering heat conduction problems

JANUSZ JANKOWSKI

The paper presents advantages of the method of Fictitious Heat Sources (FHS). The FHS method consists in the mathematical abbreviation of the solution of a certain Cauchy problem in an unbounded region. The main ideas of the method are shortly described. The way of approximation needed for numerical applications is presented. Heat conduction problems found in engineering practice are considered. The examples take into consideration the changes of the heat fluxes at the boundaries and the volume heat sources within the body.


Engineering note

Measuring and computing of inertial properties of human body

MARIO SZENTPETERI, MARIAN ZIGO

The submitted paper deals with measuring and computing of inertial properties of a human body. The first part describes a method of measuring of its moments of inertia. The second part deals with computing the position of centre of gravity and moments of inertia of a human body with respect to the three axes of cartesian coordinate system with origin in the centre of gravity. All the computing was performed by a MATHEMATICA program described in the paper. The results of our measurements and computation are compared with the results obtained by other investigators.