Karma bağlantılı kompozit plaklarda farklı sıcaklıklar etkisiyle oluşan gerilmelerin analizi
Öz
Bu çalışmada, karma bağlantı yapılarak birleştirilmiş iki kompozit plakada uygulanan farklı uniform
sıcaklıklar etkisiyle meydana gelen gerilmeler analiz edilmiştir. Karma bağlantı, pim ve yapıştırıcının
birlikte kullanılması ile meydana getirilmiştir. Analizde sonlu elemanlar metodu (SEM) kullanılmıştır.
Modelleme üç boyutlu olarak yapılmıştır. Modelleme ve çözümde, sonlu elemanlar yazılımı olan ANSYS
programından yararlanılmıştır. Oluşturulan modele hem çekme yükü hem de uniform sıcaklık yükü aynı
anda uygulanmıştır. Sıcaklığın gerilmeler üzerine etkisini gözlemlemek için çekme yükü sabit tutulmuş fakat
50, 70, 90 ve 110 oC’lik üniform sıcaklıklar uygulanmıştır. Elde edilen analiz sonuçlarına göre gerilmeler
delik çevresinde yoğunlaşmıştır. Dolayısıyla, karma bağlantı üzerinde başlayacak bir hasarın delik
çevresinden başlayacağı anlaşılmıştır. Gerilmelerin değeri, üniform sıcaklık artışındaki miktara bağlı olarak
artmaktadır.
Anahtar Kelimeler
Analysis of stresses created effect of different temperature in hybrid bonded composite plates
Abstract
Mechanical properties of glass-fiber composite
materials make them attractive for structural
applications where high strength-to-weight and
stiffness-to-weight ratios are required. Bolts, pins or
rivets have been used extensively in these
applications for transferring load between the
structural components (Wu and Hahn, 1997).
Among the different techniques for joining structural
members, mechanical fastening through a pin is a
common choice owing to low cost, simplicity, and
facilitation of disassembly for repair (Scalea,
Cappello and Cloud, 1999). Contrary to many
metallic structural members, for which the strength
of the joints is mainly governed by the shear and
tensile strengths of the pins, composite joints present
specific failure modes because of their heterogeneity
and anisotropy (Pierron, Cerisier and Grediac,
2000).Adhesive bonding technology is commonly
used these days in almost all the industries fields of
the world and this is mainly because of its high
strength-weight ratio, low cost and high efficiency
(You et al., 2007). Nonetheless, the design of safe
and cost effective bonded joints is a main challenge.
It forces on the engineer to have a good
understanding of the effect of material and
geometric parameters on the joint’s strength
(Derewonko et al., in press). In fact, the adhesive
joints experience not only mechanical loads but also
thermal loads. Because the adhesive joints consist of
materials with different mechanical and thermal
properties, the thermal strains in the joint members
might cause serious stresses (Apalak and Gunes,
2002).
According to literature survey, many researchers
have studied either adhesively bonded or pinned
single lap joint, double lap joint etc. But, the
analysis of hybrid joints designed using both
adhesively bonded and pinned single lap joints
under both thermal loads and tensile loads has not
been analyzed up till now, according to authors’
knowledge.
Therefore, in this study stresses created different
uniform temperatures effect in two composite plates
bonded together with hybrid joint were analyzed.
The hybrid joint was created using both pin and
adhesive with together. In analysis, the finite
element method (FEM) was used. Modeling and
solutions were done as three dimensional FEM.
During both modeling and solution processes, it was
utilized from ANSYS software which is a perfect
finite element code. It is known that, the hole is
needed if the pin, bolt, rivet etc. are used in the
structure for mechanical joint. Therefore, mesh
structure is very important around the hole zone for
FEM analysis because of stress concentrations.
Nonetheless, the generation of mapped mesh is very
difficult if the model has hole. However, in this
study, the mapped mesh was provided by the author.
Both tensile and uniform temperature loads were
applied on created model with together. To observe
the effect of temperatures on stresses tensile load is
applied as single value when selected constant
uniform temperature values were performed as 50,
70, 90 ve 110 oC.
According to obtained analysis results, it was shown
that thermal stresses were concentrated around the
pin hole. Therefore, it is understood that any failure
may be start from pin hole zone firstly.
The magnitudes of stresses were increased by
increasing uniform temperature, because the
differences of mechanical properties between
adhesive and composite adherents cause this result.
The thermal expansion coefficient is very important
in this increasing, particularly.
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