POHYBOVÉ ÚSTROJÍ - Společnost pro pojivové tkáně

Fig.3. Strength test scheme - unloaded state
hole 1 position (next to PS, Fig.5). For this evaluated from the curves of the loadingreason,
both the bending moment M 1 and
the corresponding stress 1 exerted at the
screw hole 1 position were calculated. The
results obtained are listed in Table 3.
The second moments of area I z of the
respective plate sections were determined
by applying Autocad R13 software.
The maximum bending stress was
calculated by using
displacement relation ( F-v) plotted by the
testing machine on a millimetre paper. For
easier evaluation of the stiffness in
bending, these curves were replaced by the
lines resulting from the regression method.
Consequently, to express the respective
regressed straight line slopes, a constant
load of F = 40 N was chosen with
corresponding variable plate deflections v
listed in Table 2.
M
σ max = [MPa] ,
Z
FEM analysis
The stiffness and strength analyses of the
C/C and C/E plates were performed by
3
where Z = I z / e [mm ] … section modulus
e [mm] … extreme fibre position
applying the FEM, COSMOS/M software
version 2.0.
with respect to the plate
neutral axis z.
a) FEM models of the plates
The C/C plate
c) Evaluation of stiffness and strength in
bending
The experimental results obtained were
An FEM model of the C/C composite plate,
based on the specimen geometry shown in
Fig.1, with main dimensions of t = 6 mm
110
LOCOMOTOR SYSTEM VOL. 6, 1999, No.2