26 research outputs found
Flexural Fatigue Behavior of Cross-Ply Laminates: An Experimental Approach
Within an experimental approach we describe
the mechanical behavior of different resin-epoxy
laminates reinforced with cross-ply Kevlar
and glass fibers under the conditions of static
and cyclic three-point bending. In static tests,
we consider the effect of stacking sequence, the
thickness of 90Β°-oriented layers, reinforcement
type on the mechanical behavior of laminates
under loading and on realization of various damage
modes leading to rupture. Cyclic loading
studies have been performed in two steps. In
the first stage, we inquire into the dependence
of the behavior and durability of four glass fiber-
reinforced laminate-types on the stacking
sequence; the second stage is devoted to studying
the dependence of cyclic strength and fatigue
behavior of laminates on the
reinforcement type. Fatigue tests are carried out
in load-control regime for glass and hybrid
(Kevlar + glass) fiber laminates. Fatigue curves
are constructed in coordinates βstress - number
of cycles until fractureβ from the criteria corresponding
to a drop in stiffness by 5 and 10%.
Analysis of the results obtained permits evaluation
of the effect of the stacking sequence and
the reinforcement type on the behavior of
cross-ply laminates in cyclic loading. The presence
of Kevlar fibers accounts for nonlinear behavior
of laminates in static tests and for low
cyclic strength in fatigue tests under three-point
bending.Π ΡΠ°ΠΌΠΊΠ°Ρ
ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Π° ΠΎΠΏΠΈΡΠ°Π½ΠΎ ΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
Π»Π°ΠΌΠΈΠ½Π°ΡΠΎΠ²
Ρ ΠΌΠ°ΡΡΠΈΡΠ΅ΠΉ ΠΈΠ· ΡΠΏΠΎΠΊΡΠΈΠ΄Π½ΠΎΠΉ ΡΠΌΠΎΠ»Ρ, ΠΏΠ΅ΡΠ΅ΠΊΡΠ΅ΡΡΠ½ΠΎ-Π°ΡΠΌΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΠΊΠ΅Π²Π»Π°ΡΠΎΠ²ΡΠΌΠΈ Π²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ
ΠΈ ΡΡΠ΅ΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ, Π² ΡΡΠ»ΠΎΠ²ΠΈΡΡ
ΡΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΈ ΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΡΠ΅Ρ
ΡΠΎΡΠ΅ΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π³ΠΈΠ±Π°. ΠΡΠΈ
ΡΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΡΠΏΡΡΠ°Π½ΠΈΡΡ
ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡΡΡ ΠΏΠΎΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎΡΡΡ ΡΠΊΠ»Π°Π΄ΠΊΠΈ ΡΠ»ΠΎΠ΅Π² ΠΈ Π²ΠΎΠ»ΠΎΠΊΠΎΠ½,
ΡΠΎΠ»ΡΠΈΠ½Ρ ΡΠ»ΠΎΠ΅Π², ΠΎΡΠΈΠ΅Π½ΡΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΠΏΠΎΠ΄ ΡΠ³Π»ΠΎΠΌ 90Β° ΠΈ Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΡΠΈΠΏΠ° Π°ΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π½Π° ΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΎΠ΅
ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ Π»Π°ΠΌΠΈΠ½Π°ΡΠΎΠ² Π² ΠΏΡΠΎΡΠ΅ΡΡΠ΅ Π½Π°Π³ΡΡΠΆΠ΅Π½ΠΈΡ, Π° ΡΠ°ΠΊΠΆΠ΅ Π½Π° ΡΠ΅Π°Π»ΠΈΠ·Π°ΡΠΈΡ ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΡΠ΅ΠΆΠΈΠΌΠΎΠ² ΠΏΠΎΠ²ΡΠ΅ΠΆΠ΄Π΅Π½ΠΈΡ, ΠΏΡΠΈΠ²ΠΎΠ΄ΡΡΠΈΡ
ΠΊ ΡΠ°Π·ΡΡΡΠ΅Π½ΠΈΡ. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΏΡΠΈ ΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΠΎΠΌ Π½Π°Π³ΡΡΠΆΠ΅Π½ΠΈΠΈ
ΡΠΎΡΡΠΎΡΡ ΠΈΠ· Π΄Π²ΡΡ
ΡΡΠ°ΠΏΠΎΠ². ΠΠ° ΠΏΠ΅ΡΠ²ΠΎΠΌ ΡΡΠ°ΠΏΠ΅ ΠΈΠ·ΡΡΠ°Π΅ΡΡΡ Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΠΏΠΎΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ
ΡΠΊΠ»Π°Π΄ΠΊΠΈ ΡΠ»ΠΎΠ΅Π² ΠΈ Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ Π½Π° ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΠΈ Π΄ΠΎΠ»Π³ΠΎΠ²Π΅ΡΠ½ΠΎΡΡΡ ΡΠ΅ΡΡΡΠ΅Ρ
ΡΠΈΠΏΠΎΠ² Π»Π°ΠΌΠΈΠ½Π°ΡΠΎΠ², Π°ΡΠΌΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΡΡΠ΅ΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ, Π½Π° Π²ΡΠΎΡΠΎΠΌ ΡΡΠ°ΠΏΠ΅ - Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΡΠΈΠΏΠ° Π°ΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π½Π° ΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΡΡ
ΠΏΡΠΎΡΠ½ΠΎΡΡΡ ΠΈ ΡΠΎΠΏΡΠΎΡΠΈΠ²Π»Π΅Π½ΠΈΠ΅ Π»Π°ΠΌΠΈΠ½Π°ΡΠΎΠ² ΠΏΡΠΈ ΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΠΎΠΌ Π½Π°Π³ΡΡΠΆΠ΅Π½ΠΈΠΈ. Π£ΡΡΠ°Π»ΠΎΡΡΠ½ΡΠ΅ ΠΈΡΠΏΡΡΠ°Π½ΠΈΡ
Π²ΡΠΏΠΎΠ»Π½Π΅Π½Ρ Π² ΠΌΡΠ³ΠΊΠΎΠΌ ΡΠ΅ΠΆΠΈΠΌΠ΅ Π½Π°Π³ΡΡΠΆΠ΅Π½ΠΈΡ Π΄Π»Ρ Π»Π°ΠΌΠΈΠ½Π°ΡΠΎΠ², Π°ΡΠΌΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΡΡΠ΅ΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ
ΠΈ Π³ΠΈΠ±ΡΠΈΠ΄Π½ΡΠΌΠΈ Π²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ (ΠΊΠ΅Π²Π»Π°Ρ+ΡΡΠ΅ΠΊΠ»ΠΎ). ΠΡΠΈΠ²ΡΠ΅ ΡΡΡΠ°Π»ΠΎΡΡΠΈ Π±ΡΠ»ΠΈ ΠΏΠΎΡΡΡΠΎΠ΅Π½Ρ Π²
ΠΊΠΎΠΎΡΠ΄ΠΈΠ½Π°ΡΠ°Ρ
Π½Π°ΠΏΡΡΠΆΠ΅Π½ΠΈΠ΅ - ΡΠΈΡΠ»ΠΎ ΡΠΈΠΊΠ»ΠΎΠ² Π΄ΠΎ ΡΠ°Π·ΡΡΡΠ΅Π½ΠΈΡ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΠΊΡΠΈΡΠ΅ΡΠΈΠ΅Π² ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΡ
ΠΆΠ΅ΡΡΠΊΠΎΡΡΠΈ Π½Π° 5 ΠΈ 10%. ΠΠ½Π°Π»ΠΈΠ· ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ ΠΎΡΠ΅Π½ΠΈΡΡ Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΠΏΠΎΡΠ»Π΅Π΄ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ
ΡΠΊΠ»Π°Π΄ΠΊΠΈ ΡΠ»ΠΎΠ΅Π² ΠΈ ΡΠΈΠΏΠ° Π°ΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π½Π° ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΠΏΠ΅ΡΠ΅ΠΊΡΠ΅ΡΡΠ½ΠΎ-Π°ΡΠΌΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
Π»Π°ΠΌΠΈΠ½Π°ΡΠΎΠ² ΠΏΡΠΈ ΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΠΎΠΌ Π½Π°Π³ΡΡΠΆΠ΅Π½ΠΈΠΈ. ΠΠ°Π»ΠΈΡΠΈΠ΅ ΠΊΠ΅Π²Π»Π°ΡΠΎΠ²ΡΡ
Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ Π² Π»Π°ΠΌΠΈΠ½Π°ΡΠ°Ρ
ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°Π΅Ρ
ΠΈΡ
Π½Π΅Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠ΅ ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΠΏΡΠΈ ΡΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΡΠΏΡΡΠ°Π½ΠΈΡΡ
ΠΈ Π½ΠΈΠ·ΠΊΡΡ ΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΡΡ ΠΏΡΠΎΡΠ½ΠΎΡΡΡ
ΠΏΡΠΈ ΡΡΡΠ°Π»ΠΎΡΡΠ½ΡΡ
ΠΈΡΠΏΡΡΠ°Π½ΠΈΡΡ
Π² ΡΡΠ»ΠΎΠ²ΠΈΡΡ
ΡΡΠ΅Ρ
ΡΠΎΡΠ΅ΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π³ΠΈΠ±Π°.Π£ ΡΠ°ΠΌΠΊΠ°Ρ
Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠ΄Ρ
ΠΎΠ΄Ρ ΠΎΠΏΠΈΡΠ°Π½ΠΎ ΠΌΠ΅Ρ
Π°Π½ΡΡΠ½Ρ ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΡ ΡΡΠ·Π½ΠΈΡ
Π»Π°ΠΌΡΠ½Π°ΡΡΠ² ΡΠ· ΠΌΠ°ΡΡΠΈΡΠ΅Ρ Π· Π΅ΠΏΠΎΠΊΡΠΈΠ΄Π½ΠΎΡ ΡΠΌΠΎΠ»ΠΈ, ΡΠΎ ΠΏΠ΅ΡΠ΅Ρ
ΡΠ΅ΡΠ½ΠΎΠ°ΡΠΌΠΎΠ²Π°Π½Ρ ΠΊΠ΅Π²Π»Π°ΡΠΎ-
Π²ΠΈΠΌΠΈ Π²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ Ρ ΡΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ, Π² ΡΠΌΠΎΠ²Π°Ρ
ΡΡΠ°ΡΠΈΡΠ½ΠΎΠ³ΠΎ Ρ ΡΠΈΠΊΠ»ΡΡΠ½ΠΎΠ³ΠΎ ΡΡΠΈ-
ΡΠΎΡΠΊΠΎΠ²ΠΎΠ³ΠΎ Π·Π³ΠΈΠ½Ρ. ΠΡΠΈ ΡΡΠ°ΡΠΈΡΠ½ΠΈΡ
Π²ΠΈΠΏΡΠΎΠ±ΡΠ²Π°Π½Π½ΡΡ
ΡΠΎΠ·Π³Π»ΡΠ΄Π°ΡΡΡΡΡ ΠΏΠΎΡΠ»ΡΠ΄ΠΎΠ²Π½ΡΡΡΡ
ΡΠΊΠ»Π°Π΄Π΅Π½Π½Ρ ΡΠ°ΡΡΠ² Ρ Π²ΠΎΠ»ΠΎΠΊΠΎΠ½, ΡΠΎΠ²ΡΠΈΠ½ΠΈ ΠΎΡΡΡΠ½ΡΠΎΠ²Π°Π½ΠΈΡ
ΠΏΡΠ΄ ΠΊΡΡΠΎΠΌ 90Β° ΡΠ°ΡΡΠ²
Ρ Π²ΠΏΠ»ΠΈΠ² ΡΠΈΠΏΡ Π°ΡΠΌΡΠ²Π°Π½Π½Ρ Π½Π° ΠΌΠ΅Ρ
Π°Π½ΡΡΠ½Ρ ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΡ Π»Π°ΠΌΡΠ½Π°ΡΡΠ² Ρ ΠΏΡΠΎΡΠ΅ΡΡ Π½Π°Π²Π°Π½ΡΠ°ΠΆΠ΅Π½Π½Ρ,
Π° ΡΠ°ΠΊΠΎΠΆ Π½Π° ΡΠ΅Π°Π»ΡΠ·Π°ΡΡΡ ΡΡΠ·Π½ΠΈΡ
ΡΠ΅ΠΆΠΈΠΌΡΠ² ΠΏΠΎΡΠΊΠΎΠ΄ΠΆΠ΅Π½Π½Ρ, ΡΠΎ ΠΏΡΠΈΠ·Π²ΠΎΠ΄ΠΈΡΡ
Π΄ΠΎ ΡΡΠΉΠ½ΡΠ²Π°Π½Π½Ρ. ΠΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½Π½Ρ ΠΏΡΠΈ ΡΠΈΠΊΠ»ΡΡΠ½ΠΎΠΌΡ Π½Π°Π²Π°Π½ΡΠ°ΠΆΠ΅Π½Π½Ρ ΡΠΊΠ»Π°Π΄Π°ΡΡΡΡΡ Π·
Π΄Π²ΠΎΡ
Π΅ΡΠ°ΠΏΡΠ². ΠΠ° ΠΏΠ΅ΡΡΠΎΠΌΡ Π΅ΡΠ°ΠΏΡ ΡΠΎΠ·Π³Π»ΡΠ΄Π°ΡΡΡΡΡ Π²ΠΏΠ»ΠΈΠ² ΠΏΠΎΡΠ»ΡΠ΄ΠΎΠ²Π½ΠΎΡΡΡ ΡΠΊΠ»Π°Π΄Π΅Π½Π½Ρ
ΡΠ°ΡΡΠ² Ρ Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ Π½Π° ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΡ Ρ Π΄ΠΎΠ²Π³ΠΎΠ²ΡΡΠ½ΡΡΡΡ ΡΠΎΡΠΈΡΡΠΎΡ
ΡΠΈΠΏΡΠ² Π°ΡΠΌΠΎΠ²Π°Π½ΠΈΡ
ΡΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ Π»Π°ΠΌΡΠ½Π°ΡΡΠ², Π½Π° Π΄ΡΡΠ³ΠΎΠΌΡ Π΅ΡΠ°ΠΏΡ - Π²ΠΏΠ»ΠΈΠ² ΡΠΈΠΏΡ Π°ΡΠΌΡΠ²Π°Π½Π½Ρ Π½Π°
ΡΠΈΠΊΠ»ΡΡΠ½Ρ ΠΌΡΡΠ½ΡΡΡΡ Ρ ΠΎΠΏΡΡ Π»Π°ΠΌΡΠ½Π°ΡΡΠ² ΠΏΡΠΈ ΡΠΈΠΊΠ»ΡΡΠ½ΠΎΠΌΡ Π½Π°Π²Π°Π½ΡΠ°ΠΆΠ΅Π½Π½Ρ. ΠΠΈΠΏΡΠΎΠ±ΡΠ²Π°Π½Π½Ρ
Π½Π° Π²ΡΠΎΠΌΡ Π²ΠΈΠΊΠΎΠ½Π°Π½ΠΎ Ρ ΠΌ βΡΠΊΠΎΠΌΡ ΡΠ΅ΠΆΠΈΠΌΡ Π½Π°Π²Π°Π½ΡΠ°ΠΆΠ΅Π½Π½Ρ Π΄Π»Ρ Π°ΡΠΌΠΎΠ²Π°Π½ΠΈΡ
ΡΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ Ρ Π³ΡΠ±ΡΠΈΠ΄Π½ΠΈΠΌΠΈ Π²ΠΎΠ»ΠΎΠΊΠ½Π°ΠΌΠΈ (ΠΊΠ΅Π²Π»Π°Ρ + ΡΠΊΠ»ΠΎ) Π»Π°ΠΌΡΠ½Π°ΡΡΠ². ΠΠ° ΠΎΡΠ½ΠΎΠ²Ρ
ΠΊΡΠΈΡΠ΅ΡΡΡΠ² Π·Π½ΠΈΠΆΠ΅Π½Π½Ρ ΠΆΠΎΡΡΡΠΊΠΎΡΡΡ Π½Π° 5 Ρ 10% Π² ΠΊΠΎΠΎΡΠ΄ΠΈΠ½Π°ΡΠ°Ρ
Π½Π°ΠΏΡΡΠΆΠ΅Π½Π½Ρ -
ΡΠΈΡΠ»ΠΎ ΡΠΈΠΊΠ»ΡΠ² Π΄ΠΎ ΡΡΠΉΠ½ΡΠ²Π°Π½Π½Ρ ΠΏΠΎΠ±ΡΠ΄ΠΎΠ²Π°Π½ΠΎ ΠΊΡΠΈΠ²Ρ ΡΡΠΎΠΌΠΈ. ΠΠ½Π°Π»ΡΠ· ΠΎΡΡΠΈΠΌΠ°Π½ΠΈΡ
ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡΠ² Π΄ΠΎΠ·Π²ΠΎΠ»ΡΡ ΠΎΡΡΠ½ΠΈΡΠΈ Π²ΠΏΠ»ΠΈΠ² ΠΏΠΎΡΠ»ΡΠ΄ΠΎΠ²Π½ΠΎΡΡΡ ΡΠΊΠ»Π°Π΄Π΅Π½Π½Ρ ΡΠ°ΡΡΠ² Ρ ΡΠΈΠΏΡ
Π°ΡΠΌΡΠ²Π°Π½Π½Ρ Π½Π° ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΡ ΠΏΠ΅ΡΠ΅Ρ
ΡΠ΅ΡΠ½ΠΎΠ°ΡΠΌΠΎΠ²Π°Π½ΠΈΡ
Π»Π°ΠΌΡΠ½Π°ΡΡΠ² ΠΏΡΠΈ ΡΠΈΠΊΠ»ΡΡΠ½ΠΎΠΌΡ
Π½Π°Π²Π°Π½ΡΠ°ΠΆΠ΅Π½Π½Ρ. ΠΠ°ΡΠ²Π½ΡΡΡΡ ΠΊΠ΅Π²Π»Π°ΡΠΎΠ²ΠΈΡ
Π²ΠΎΠ»ΠΎΠΊΠΎΠ½ Ρ Π»Π°ΠΌΡΠ½Π°ΡΠ°Ρ
Π·Π°ΠΏΠ΅Π·ΡΡΡ ΡΡ
Π½Π΅Π»ΡΠ½ΡΠΉΠ½Ρ
ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΡ ΠΏΡΠΈ ΡΡΠ°ΡΠΈΡΠ½ΠΈΡ
Π²ΠΈΠΏΡΠΎΠ±ΡΠ²Π°Π½Π½ΡΡ
Ρ Π½ΠΈΠ·ΡΠΊΡ ΡΠΈΠΊΠ»ΡΡΠ½Ρ ΠΌΡΡΠ½ΡΡΡΡ ΠΏΡΠΈ
Π²ΠΈΠΏΡΠΎΠ±ΡΠ²Π°Π½Π½ΡΡ
Π½Π° Π²ΡΠΎΠΌΡ Π² ΡΠΌΠΎΠ²Π°Ρ
ΡΡΠΈΡΠΎΡΠΊΠΎΠ²ΠΎΠ³ΠΎ Π·Π³ΠΈΠ½Ρ
Experimental analysis of behavior and damage of sandwich composite materials in three-point bending. Part 1. Static tests and stiffness degradation at failure studies
The analysis of stiffness and the identification
of rupture mechanisms during and after static
tests of sandwich panels and their components
have been investigated. The sandwich panels,
having cross-ply laminates skins made of glass
fibre and epoxy resin were manufactured by
vacuum moulding and subjected to three-point
bending tests. Two PVC cores of similar type
but with differing densities were investigated.
The effect of core density and its thickness on
the behavior and the damage was highlighted.
In terms of stiffness and load at failure, the
sandwich structure has better mechanical
characteristics compared to its components.ΠΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΎ Π΄ΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½ΠΎ Π·ΠΌΡΠ½Ρ ΠΆΠΎΡΡΡΠΊΠΎΡΡΡ ΡΠ° ΠΏΡΠΎΠ°Π½Π°Π»ΡΠ·ΠΎΠ²Π°Π½ΠΎ ΠΌΠ΅Ρ
Π°Π½ΡΠ·ΠΌΠΈ
ΡΡΠΉΠ½ΡΠ²Π°Π½Π½Ρ ΠΏΡΠΈ ΡΡΠ°ΡΠΈΡΠ½ΠΈΡ
Π²ΠΈΠΏΡΠΎΠ±ΡΠ²Π°Π½Π½ΡΡ
Π±Π°Π³Π°ΡΠΎΡΠ°ΡΠΎΠ²ΠΈΡ
ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ½ΠΈΡ
ΠΏΠ»Π°ΡΡΠΈΠ½ Ρ ΡΡ
ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΡΠ². ΠΠ°Π³Π°ΡΠΎΡΠ°ΡΠΎΠ²Ρ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ½Ρ ΠΏΠ»Π°ΡΡΠΈΠ½ΠΈ Π· ΠΏΠ΅ΡΠ΅Ρ
ΡΠ΅ΡΠ½ΠΈΠΌΠΈ
ΡΠ°ΡΠ°ΠΌΠΈ Π·Ρ ΡΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π° ΡΠ° Π΅ΠΏΠΎΠΊΡΠΈΠ΄Π½ΠΎΡ ΡΠΌΠΎΠ»ΠΈ, ΡΠΎ Π²ΠΈΠ³ΠΎΡΠΎΠ²Π»Π΅Π½Ρ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ Π²Π°ΠΊΡΡΠΌΠ½ΠΎΡ Π²ΡΠ΄Π»ΠΈΠ²ΠΊΠΈ, ΠΏΡΠ΄Π΄Π°Π²Π°Π»ΠΈ Π½Π°Π²Π°Π½ΡΠ°ΠΆΠ΅Π½Π½Ρ ΡΡΠΈΡΠΎΡΠΊΠΎΠ²ΠΈΠΌ Π·Π³ΠΈΠ½ΠΎΠΌ. ΠΠΎΡΠ»ΡΠ΄ΠΆΡΠ²Π°Π»ΠΈ Π΄Π²Π° Π²Π°ΡΡΠ°Π½ΡΠΈ ΠΏΠ»Π°ΡΡΠΈΠ½ Π· ΠΎΠ΄Π½ΠΎΡΠΈΠΏΠ½ΠΈΠΌΠΈ Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ°ΠΌΠΈ Π· ΠΏΠΎΠ»Ρ-
Π²ΡΠ½ΡΠ»ΠΎΠΏΠ»Π°ΡΡΠ° ΡΡΠ·Π½ΠΎΡ ΡΡΠ»ΡΠ½ΠΎΡΡΡ. Π ΠΎΠ·Π³Π»ΡΠ½ΡΡΠΎ Π²ΠΏΠ»ΠΈΠ² ΡΡΠ»ΡΠ½ΠΎΡΡΡ Ρ ΡΠΎΠ²ΡΠΈΠ½ΠΈ Π²Π½ΡΡΡΡΡΠ½ΡΠΎΠ³ΠΎ
ΡΠ°ΡΡ Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ° Π½Π° ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΡ ΡΠ° ΠΏΠΎΡΠΊΠΎΠ΄ΠΆΠ΅Π½Π½Ρ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ°. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ,
ΡΠΎ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡ ΡΠ· Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ΅ΠΌ Π²Π΅Π»ΠΈΠΊΠΎΡ ΡΡΠ»ΡΠ½ΠΎΡΡΡ ΠΌΠ°Ρ Π±ΡΠ»ΡΡ Π²ΠΈΡΠΎΠΊΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠΈ ΡΡΠ°ΡΠΈΡΠ½ΠΎΡ ΠΌΡΡΠ½ΠΎΡΡΡ Ρ ΡΡΡΠΉΠΊΠΎΡΡΡ ΠΏΠΎΡΡΠ²Π½ΡΠ½ΠΎ Π· ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠΎΠΌ ΡΠ·
Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ΅ΠΌ ΠΌΠ΅Π½ΡΠΎΡ ΡΡΠ»ΡΠ½ΠΎΡΡΡ.ΠΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΎ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΎ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ ΠΆΠ΅ΡΡΠΊΠΎΡΡΠΈ ΠΈ ΠΏΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Ρ ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΡ ΡΠ°Π·ΡΡΡΠ΅Π½ΠΈΡ
ΠΏΡΠΈ ΡΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈΡΠΏΡΡΠ°Π½ΠΈΡΡ
ΠΌΠ½ΠΎΠ³ΠΎΡΠ»ΠΎΠΉΠ½ΡΡ
ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ½ΡΡ
ΠΏΠ»Π°ΡΡΠΈΠ½ ΠΈ ΠΈΡ
ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΠΎΠ².
ΠΠ½ΠΎΠ³ΠΎΡΠ»ΠΎΠΉΠ½ΡΠ΅ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ½ΡΠ΅ ΠΏΠ»Π°ΡΡΠΈΠ½Ρ Ρ ΠΏΠ΅ΡΠ΅ΠΊΡΠ΅ΡΡΠ½ΡΠΌΠΈ ΡΠ»ΠΎΡΠΌΠΈ ΠΈΠ· ΡΡΠ΅ΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π° ΠΈ
ΡΠΏΠΎΠΊΡΠΈΠ΄Π½ΠΎΠΉ ΡΠΌΠΎΠ»Ρ, ΠΈΠ·Π³ΠΎΡΠΎΠ²Π»Π΅Π½Π½ΡΠ΅ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ Π²Π°ΠΊΡΡΠΌΠ½ΠΎΠΉ ΠΎΡΠ»ΠΈΠ²ΠΊΠΈ, ΠΏΠΎΠ΄Π²Π΅ΡΠ³Π°Π»ΠΈ Π½Π°Π³ΡΡΠΆΠ΅Π½ΠΈΡ
ΡΡΠ΅Ρ
ΡΠΎΡΠ΅ΡΠ½ΡΠΌ ΠΈΠ·Π³ΠΈΠ±ΠΎΠΌ. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π»ΠΈ Π΄Π²Π° Π²Π°ΡΠΈΠ°Π½ΡΠ° ΠΏΠ»Π°ΡΡΠΈΠ½ Ρ ΠΎΠ΄Π½ΠΎΡΠΈΠΏΠ½ΡΠΌΠΈ Π½Π°ΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»ΡΠΌΠΈ
ΠΈΠ· ΠΏΠ΅Π½ΠΎΠ²ΠΈΠ½ΠΈΠ»ΠΎΠΏΠ»Π°ΡΡΠ° ΡΠ°Π·Π»ΠΈΡΠ½ΠΎΠΉ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ. Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½ΠΎ Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΈ ΡΠΎΠ»ΡΠΈΠ½Ρ
Π²Π½ΡΡΡΠ΅Π½Π½Π΅Π³ΠΎ ΡΠ»ΠΎΡ Π½Π°ΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»Ρ Π½Π° ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΠΈ ΠΏΠΎΠ²ΡΠ΅ΠΆΠ΄Π΅Π½ΠΈΠ΅ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ°. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ
ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡ Ρ Π½Π°ΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»Π΅ΠΌ Π±ΠΎΠ»ΡΡΠ΅ΠΉ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΎΠ±Π»Π°Π΄Π°Π΅Ρ Π±ΠΎΠ»Π΅Π΅ Π²ΡΡΠΎΠΊΠΈΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ
ΡΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΡΠΎΡΠ½ΠΎΡΡΠΈ ΠΈ ΡΡΡΠΎΠΉΡΠΈΠ²ΠΎΡΡΠΈ ΠΏΠΎ ΡΡΠ°Π²Π½Π΅Π½ΠΈΡ Ρ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠΎΠΌ, ΠΈΠΌΠ΅ΡΡΠΈΠΌ Π½Π°ΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»Ρ
ΠΌΠ΅Π½ΡΡΠ΅ΠΉ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ
Experimental Analysis of Behavior and Damage of Sandwich Composite Materials in Three-Point Bending. Part 2. Fatigue Test Results and Damage Mechanisms
ΠΡΠΏΠΎΠ»Π½Π΅Π½Ρ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ ΠΆΠ΅ΡΡΠΊΠΎΡΡΠΈ ΠΈ ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΠΎΠ² ΠΏΠΎΠ²ΡΠ΅ΠΆΒΠ΄Π΅Π½ΠΈΡ ΠΏΡΠΈ ΡΡΡΠ°Π»ΠΎΡΡΠ½ΡΡ
ΠΈΡΠΏΡΡΠ°Π½ΠΈΡΡ
ΠΌΠ½ΠΎΠ³ΠΎΡΠ»ΠΎΠΈΜΠ½ΡΡ
ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ½ΠΈΡ
ΠΏΠ»Π°ΡΡΠΈΠ½ Ρ Π½Π°ΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»Π΅ΠΌ ΠΈΠ· ΠΏΠ΅Π½ΠΎΠ²ΠΈΠ½ΠΈΠ»ΠΎΠΏΠ»Π°ΡΡΠ°. ΠΠ½ΠΎΠ³ΠΎΡΠ»ΠΎΠΈΜΠ½ΡΠ΅ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ½ΡΠ΅ ΠΏΠ»Π°ΡΡΠΈΠ½Ρ Ρ ΠΏΠ΅ΡΠ΅ΠΊΡΠ΅ΡΡΠ½ΡΠΌΠΈ ΡΠ»ΠΎΡΠΌΠΈ ΠΈΠ· ΡΡΠ΅ΠΊΠ»ΠΎΒ Π²ΠΎΠ»ΠΎΠΊΠ½Π° ΠΈ ΡΠΏΠΎΠΊΡΠΈΠ΄Π½ΠΎΠΈΜ ΡΠΌΠΎΠ»Ρ, ΠΈΠ·Π³ΠΎΡΠΎΠ²Π»Π΅Π½Π½ΡΠ΅ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ Π²Π°ΠΊΡΡΠΌΠ½ΠΎΠΈΜ ΠΎΡΠ»ΠΈΠ²ΠΊΠΈ, ΠΏΠΎΠ΄Π²Π΅ΡΠ³Π°Π»ΠΈ Π½Π°Π³ΡΡΒΠΆΠ΅Π½ΠΈΡ ΡΡΠ΅Ρ
ΡΠΎΡΠ΅ΡΠ½ΡΠΌ ΠΈΠ·Π³ΠΈΠ±ΠΎΠΌ. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π»ΠΈ Π΄Π²Π° Π²Π°ΡΠΈΠ°Π½ΡΠ° ΠΏΠ»Π°ΡΡΠΈΠ½ Ρ ΠΎΠ΄Π½ΠΎΡΠΈΠΏΠ½ΡΠΌΠΈ Π½Π°ΠΏΠΎΠ»ΒΠ½ΠΈΡΠ΅Π»ΡΠΌΠΈ ΠΈΠ· ΠΏΠ΅Π½ΠΎΠ²ΠΈΠ½ΠΈΠ»ΠΎΠΏΠ»Π°ΡΡΠ° ΡΠ°Π·Π»ΠΈΡΠ½ΠΎΠΈΜ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ. Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½ΠΎ Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΈ ΡΠΎΠ»ΡΠΈΠ½Ρ Π²Π½ΡΡΡΠ΅Π½Π½Π΅Π³ΠΎ ΡΠ»ΠΎΡ Π½Π°ΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»Ρ Π½Π° ΠΏΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΠΈ ΠΏΠΎΠ²ΡΠ΅ΠΆΠ΄Π΅Π½ΠΈΠ΅ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ°. Π‘ ΠΈΡΠΏΠΎΠ»ΡΒΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ Π΄Π²ΡΡ
ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΠΌΠΎΠ΄Π΅Π»Π΅ΠΈΜ ΠΈ ΠΊΡΠΈΡΠ΅ΡΠΈΡ ΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΠΎΠΈΜ Π΄ΠΎΠ»Π³ΠΎΠ²Π΅ΡΠ½ΠΎΡΡΠΈ ΠΏΠΎΡΡΡΠΎΠ΅Π½Ρ ΠΊΡΠΈΠ²ΡΠ΅ ΡΡΡΠ°Π»ΠΎΡΡΠΈ ΠΈ Π²ΡΠΏΠΎΠ»Π½Π΅Π½ ΠΈΡ
ΡΡΠ°Π²Π½ΠΈΡΠ΅Π»ΡΠ½ΡΠΈΜ Π°Π½Π°Π»ΠΈΠ· Ρ ΠΈΠΌΠ΅ΡΡΠΈΠΌΠΈΡΡ Π»ΠΈΡΠ΅ΡΠ°ΡΡΡΠ½ΡΠΌΠΈ Π΄Π°Π½Π½ΡΠΌΠΈ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡ SD 2 Ρ Π½Π°ΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»Π΅ΠΌ Π±ΠΎΠ»ΡΡΠ΅ΠΈΜ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ ΠΎΠ±Π»Π°Π΄Π°Π΅Ρ Π±ΠΎΠ»Π΅Π΅ Π²ΡΡΠΎΠΊΠΈΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ ΡΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΈΜ ΠΏΡΠΎΡΠ½ΠΎΡΡΠΈ ΠΈ ΡΡΡΠΎΠΈΜΡΠΈΠ²ΠΎΡΡΠΈ, Π° ΡΠ°ΠΊΠΆΠ΅ ΡΡΡΠ°Π»ΠΎΡΡΠ½ΠΎΠΈΜ ΠΏΡΠΎΡΒΠ½ΠΎΡΡΠΈ ΠΏΠΎ ΡΡΠ°Π²Π½Π΅Π½ΠΈΡ Ρ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠΎΠΌ SD 1 Ρ Π½Π°ΠΏΠΎΠ»Π½ΠΈΡΠ΅Π»Π΅ΠΌ ΠΌΠ΅Π½ΡΡΠ΅ΠΈΜ ΠΏΠ»ΠΎΡΠ½ΠΎΡΡΠΈ.ΠΡΠΎΠ²Π΅Π΄Π΅Π½ΠΎ Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½Ρ Π΄ΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½Π½Ρ Π·ΠΌΡΠ½ΠΈ ΠΆΠΎΡΡΡΠΊΠΎΡΡΡ ΡΠ° ΠΌΠ΅Ρ
Π°Π½ΡΠ·ΠΌΡΠ² ΠΏΠΎΡΠΊΠΎΠ΄ΠΆΠ΅Π½Π½Ρ
ΠΏΡΠΈ Π²ΠΈΠΏΡΠΎΠ±ΡΠ²Π°Π½Π½ΡΡ
Π½Π° Π²ΡΠΎΠΌΡ Π±Π°Π³Π°ΡΠΎΡΠ°ΡΠΎΠ²ΠΈΡ
ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ½ΠΈΡ
ΠΏΠ»Π°ΡΡΠΈΠ½
ΡΠ· Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ΅ΠΌ ΡΠ· ΠΏΡΠ½ΠΎΠ²ΡΠ½ΡΠ»ΠΎΠΏΠ»Π°ΡΡΠ°. ΠΠ°Π³Π°ΡΠΎΡΠ°ΡΠΎΠ²Ρ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ½Ρ ΠΏΠ»Π°ΡΡΠΈΠ½ΠΈ Π·
ΠΏΠ΅ΡΠ΅Ρ
ΡΠ΅ΡΠ½ΠΈΠΌΠΈ ΡΠ°ΡΠ°ΠΌΠΈ Π·Ρ ΡΠΊΠ»ΠΎΠ²ΠΎΠ»ΠΎΠΊΠ½Π° ΡΠ° Π΅ΠΏΠΎΠΊΡΠΈΠ΄Π½ΠΎΡ ΡΠΌΠΎΠ»ΠΈ, Π²ΠΈΠ³ΠΎΡΠΎΠ²Π»Π΅Π½Ρ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ
Π²Π°ΠΊΡΡΠΌΠ½ΠΎΠ³ΠΎ Π²ΡΠ΄Π»ΠΈΠ²Ρ, ΠΏΡΠ΄Π΄Π°Π²Π°Π»ΠΈ Π½Π°Π²Π°Π½ΡΠ°ΠΆΠ΅Π½Π½Ρ ΡΡΠΈΡΠΎΡΠΊΠΎΠ²ΠΈΠΌ Π·Π³ΠΈΠ½ΠΎΠΌ. ΠΠΎΡΠ»ΡΠ΄ΠΆΡΠ²Π°Π»ΠΈ
Π΄Π²Π° Π²Π°ΡΡΠ°Π½ΡΠ° ΠΏΠ»Π°ΡΡΠΈΠ½ Π· ΠΎΠ΄Π½ΠΎΡΠΈΠΏΠ½ΠΈΠΌΠΈ Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ°ΠΌΠΈ Π· ΠΏΡΠ½ΠΎΠ²ΡΠ½ΡΠ»ΠΎΠΏΠ»Π°ΡΡΠ°
ΡΡΠ·Π½ΠΎΡ ΡΡΠ»ΡΠ½ΠΎΡΡΡ. Π ΠΎΠ·Π³Π»ΡΠ½ΡΡΠΎ Π²ΠΏΠ»ΠΈΠ² ΡΡΠ»ΡΠ½ΠΎΡΡΡ Ρ ΡΠΎΠ²ΡΠΈΠ½ΠΈ Π²Π½ΡΡΡΡΡΠ½ΡΠΎΠ³ΠΎ
ΡΠ°ΡΡ Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ° Π½Π° ΠΏΠΎΠ²Π΅Π΄ΡΠ½ΠΊΡ ΡΠ° ΠΏΠΎΡΠΊΠΎΠ΄ΠΆΠ΅Π½Π½Ρ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠ°. ΠΠ· Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½ΡΠΌ
Π΄Π²ΠΎΡ
ΡΡΠ·Π½ΠΈΡ
ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ ΡΠ° ΠΊΡΠΈΡΠ΅ΡΡΡ ΡΠΈΠΊΠ»ΡΡΠ½ΠΎΡ Π΄ΠΎΠ²Π³ΠΎΠ²ΡΡΠ½ΠΎΡΡΡ ΠΏΠΎΠ±ΡΠ΄ΠΎΠ²Π°Π½ΠΎ
ΠΊΡΠΈΠ²Ρ Π²ΡΠΎΠΌΠ»Π΅Π½ΠΎΡΡΡ Ρ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΎ ΡΡ
ΠΏΠΎΡΡΠ²Π½ΡΠ»ΡΠ½ΠΈΠΉ Π°Π½Π°Π»ΡΠ· ΡΠ· Π²ΡΠ΄ΠΎΠΌΠΈΠΌΠΈ Π»ΡΡΠ΅ΡΠ°ΡΡΡΠ½ΠΈΠΌΠΈ
Π΄Π°Π½ΠΈΠΌΠΈ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΠΎ ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡ SD 2 Π· Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ΅ΠΌ Π²Π΅Π»ΠΈΠΊΠΎΡ ΡΡΠ»ΡΠ½ΠΎΡΡΡ
ΠΌΠ°Ρ Π±ΡΠ»ΡΡ Π²ΠΈΡΠΎΠΊΡ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠΈ ΡΡΠ°ΡΠΈΡΠ½ΠΎΡ ΠΌΡΡΠ½ΠΎΡΡΡ Ρ ΡΡΡΠΉΠΊΠΎΡΡΡ ΡΠ° ΡΡΠΎΠΌΠ½ΠΎΡ
ΠΌΡΡΠ½ΠΎΡΡΡ ΠΏΠΎΡΡΠ²Π½ΡΠ½ΠΎ Π· ΠΊΠΎΠΌΠΏΠΎΠ·ΠΈΡΠΎΠΌ SD 1 ΡΠ· Π½Π°ΠΏΠΎΠ²Π½ΡΠ²Π°ΡΠ΅ΠΌ ΠΌΠ΅Π½ΡΠΎΡ ΡΡΠ»ΡΠ½ΠΎΡΡΡ.The analysis o f stiffness degradation and the
identification o f damage mechanisms during and
after fatigue tests of sandwich panels with PVC
foam cores have been performed. The sandwich
panels with cross-ply laminates skins made of
glass fiber and epoxy resin were manufactured
by vacuum moulding and subjected to three-point
bending tests. Two PVC cores of similar type but
with differing densities were investigated. The effect
o f core density and thickness on the damage
behavior was highlighted. Using the cyclic life
criterion, fatigue curves were plotted according
to two models and compared with those o f the literature.
It has been demonstrated that the
sandwich SD 2, with the higher core density, withstands
a higher load and possesses greater rigidity
in static tests, combined with an enhanced
fatigue resistance when compared to sandwich
SD 1 which has a lower core density
Heat generation and transfer in automotive dry clutch engagement
Dynamic behaviour of automotive dry clutches depends on the frictional characteristics of the contact between the friction lining material, the flywheel, and the pressure plate during the clutch engagement process. During engagement due to high interfacial slip and relatively high contact pressures, generated friction gives rise to contact heat, which affects the material behaviour and the associated frictional characteristics. In practice excess interfacial slipping and generated heat during torque transmission can result in wear of the lining, thermal distortion of the friction disc, and reduced useful life of the clutch. This paper provides measurement of friction lining characteristics for dry clutches for new and worn state under representative operating conditions pertaining to interfacial slipping during clutch engagement, applied contact pressures, and generated temperatures. An analytical thermal partitioning network model of the clutch assembly, incorporating the flywheel, friction lining, and the pressure plate is presented, based upon the principle of conservation of energy. The results of the analysis show a higher coefficient of friction for the new lining material which reduces the extent of interfacial slipping during clutch engagement, thus reducing the frictional power loss and generated interfacial heating. The generated heat is removed less efficiently from worn lining. This might be affected by different factors observed such as the reduced lining thickness and the reduction of density of the material but mainly because of poorer thermal conductivity due to the depletion of copper particles in its microstructure as the result of wear. The study integrates frictional characteristics, microstructural composition, mechanisms of heat generation, effect of lining wear, and heat transfer in a fundamental manner, an approach not hitherto reported in literature
Vibration suppression for high speed railway bridges using fluid viscous dampers
The results of experimental and theoritical investigations of railway bridges have shown the significant dynamic responses exceeding that anticipated on certain railway bridges, such as a resonance phenomenon who have a great effect in the bridge. Alternatively , the use of structural control systems devices might be a very promising solution to attenuate undesirable vibration. The aim of this study, first, is to investigate the posibility of reducing the acceleration in an acceptable level by using fluid viscous dampers. The bridge-damper system is described by a single-degree-of-freedom model. The ,dampers are connected between the bottom surface of the bridge deck and the abutment, Finallay a linearisation model and a comparative study in order to investigate the effect of the nonlinearite of the device in the dynamic response of the system
Flexural fatigue behavior of cross-ply laminates.An experimental approach
Within an experimental approach we describe the mechanical behavior of different resin-epoxy laminates reinforced with cross-ply Kevlar and glass fibers under conditions of static and cyclic three-point bending. In static tests, we consider the effect of stacking sequence, the thickness of 90Β°-oriented layers, reinforcement type on the mechanical behavior of laminates under loading and on realization of various damage modes leading to rupture. Cyclic loading studies have been performed in two steps. In the first stage, we inquire into the dependence of the behavior and durability of four glass fiber-reinforced laminate-types on the stacking sequence; the second stage is devoted to studying the dependence of cyclic strength and fatigue behavior of laminates on the reinforcement type. Fatigue tests are carried out in load-control regime for glass and hybrid (Kevlar + glass) fiber laminates. Fatigue curves are constructed in coordinates βstress β number of cycles until fractureβ from the criteria corresponding to a drop in stiffness by 5 and 10%. Analysis of the results obtained permits evaluation of the effect of the stacking sequence and the reinforcement type on the behavior of cross-ply laminates in cyclic loading. The presence of Kevlar fibers accounts for nonlinear behavior of laminates in static tests and for low cyclic strength in fatigue tests under three-point bendin
Local thermal non-equilibrium effects in the Horton-Rogers-Lapwood problem with a free surface
The onset of thermoconvective instability in a modified Horton-Rogers-Lapwood problem is here investigated. Since the local thermal non equilibrium model is employed, two temperatures, one for the solid phase and one for the fluid phase, are considered. The porous layer is saturated by a Newtonian fluid and the lower plate is impermeable. A horizontal free surface is assumed as top boundary. The free surface is subject to a uniform pressure condition and a third kind boundary condition rules the heat transfer with the external environment. The lower boundary is subject to a uniform heat flux modelled by means of Model A proposed by Amiri et\ua0al. [1]. The linear stability of the basic state is investigated by means of normal modes method. An eigenvalue problem characterised by ordinary differential equations is obtained. This eigenvalue problem is governed by a number of parameters. This feature gives the chance of investigating different limiting cases. Some of these cases are solved analytically. These analytical solutions are employed as benchmark and as guess values for the numerical solver employed to solve the general case: a fourth order Runge-Kutta method coupled with the shooting method. The critical values of the stability parameter for the onset of convective instability are obtained for a number of cases
Analyzing the effect of large rotations on the seismic response of structures subjected to foundation local uplift
This work deals with seismic analysis of structures by taking into account soil-structure interaction where the structure is modeled by an equivalent flexible beam mounted on a rigid foundation that is supported by a Winkler like soil. The foundation is assumed to undergo local uplift and the rotations are considered to be large. The coupling of the system is represented by a series of springs and damping elements that are distributed over the entire width of the foundation. The non-linear equations of motion of the system were derived by taking into account the equilibrium of the coupled foundation-structure system where the structure was idealized as a single-degree-of-freedom. The seismic response of the structure was calculated under the occurrence of foundation uplift for both large and small rotations. The non-linear differential system of equations was integrated by using the Matlab command ode15s. The maximum response has been determined as function of the intensity of the earthquake, the slenderness of the structure and the damping ratio. It was found that considering local uplift with small rotations of foundation under seismic loading leads to unfavorable structural response in comparison with the case of large rotations
Analyzing the effect of large rotations on the seismic response of structures subjected to foundation local uplift
This work deals with seismic analysis of structures by taking into account soil-structure interaction where the structure is modeled by an equivalent flexible beam mounted on a rigid foundation that is supported by a Winkler like soil. The foundation is assumed to undergo local uplift and the rotations are considered to be large. The coupling of the system is represented by a series of springs and damping elements that are distributed over the entire width of the foundation. The non-linear equations of motion of the system were derived by taking into account the equilibrium of the coupled foundation-structure system where the structure was idealized as a single-degree-of-freedom. The seismic response of the structure was calculated under the occurrence of foundation uplift for both large and small rotations. The non-linear differential system of equations was integrated by using the Matlab command ode15s. The maximum response has been determined as function of the intensity of the earthquake, the slenderness of the structure and the damping ratio. It was found that considering local uplift with small rotations of foundation under seismic loading leads to unfavorable structural response in comparison with the case of large rotations
Modeling damage of the hydrogen enhanced localized plasticity in stress corrosion cracking
Stress corrosion cracking is an important and complex mode of failure in high-performance structural metals operating in deleterious environments, due to metallurgical, mechanical, and electrochemical factors. Depending on the material/solution system, the stress corrosion cracking mechanism may involve a combination of hydrogen embrittlement (HE) and anodic dissolution. In this article, a numerical model for predicting the mechanical behavior of hydrogen-induced damage in stress corrosion cracking is described. The methodology of modeling used in this study is based on the thermodynamics of continuum solids and elastoplastic damage. This model is based on a stress corrosion mechanism that occurs through the simultaneous interaction of hydrogen and plasticity. This mechanism is also called hydrogen-enhanced localized plasticity, which is a viable mechanism for hydrogen embrittlement. The model is applied to the fatigue damage problems of nuclear reactor pipe, and the results are compared with published fatigue life data obtained experimentall