Transcript Sandwich Construction

Sandwich Construction
Eng. Marco Leite
Prof. Manuel de Freitas
Prof. Arlindo Silva
Sandwich Construction






2
Introdução
Leis Constitutivas
Exemplo
Design procedures
Aplicações
Bibliografia
NOV 2004
Introdução



3
Origem
Princípio Sandwich
Vantagens e Desvantagens
NOV 2004
Origem

II Gerra Mundial – de Havilland Mosquito TT35 TA639
–
4
Fuselagem  Plywood/Balsa/Plywood

“Mosquito. The timber terror. Light, fast, deadly.”

“The excellent performance demonstrated by this airplane
had convinced numerous aircraft designers of the
superiority of sandwich structure as a means of
constructing more efficient airplanes”

Falta de materiais na G.B. no auge na II Guerra Mundial
NOV 2004
Origem

II Guerra Mundial – Vultee BT15 (USA)
–
5
Fuselagem  Fibra de vidro em matriz de poliester com núcleo
em honeycomb de fibra de vidro ou núcleo de balsa.
NOV 2004
Princípio Sandwich
(c) web core
(d) corrugated core
6
NOV 2004
Vantagens e desvantagens
7
Vantagens
Desvantagens
Alta Resistência Específica
Perigoso para a saúde durante a
construção (Resinas)
Alta Rigidez Específica
Fracas possibilidades de reciclagem
(compósitos)
Baixo Peso
Falta de informação nos engenheiros
e designers
Isolamento Térmico e Acústico
Problemas de temperatura
Capacidade de resistência à corrosão
Mudança de mentalidades
Facilidade de formas completas
Controlo de Qualidade
Capacidade de absorção de Energia
Variedade de critérios de rotura
Poucas peças estruturais necessárias
Incompatibilidade de materiais
Múltiplas possibilidades de escolha de
NOV materiais
2004
Leis Constitutivas
Leis Constitutivas







9
Teoria clássica vs Teoria 1ª ordem
Campo de deslocamentos
Campo de deformações
Relação Tensão-Extensão  TCL
Leis Constitutivas  TCL
Relação Tensão-Extensão  1ª ordem
Leis Constitutivas  1ª ordem
NOV 2004
Teoria clássica vs Teoria 1ª ordem
Teoria Clássica Laminados
10
NOV 2004
Teoria 1ª ordem
Campo de Deslocamentos
Teoria Clássica
Laminados
u  x, y , z   u 0  x , y , z   z  x  x , y 
w 0
x
w
y   0
y
x  
v  x, y, z   v0  x, y, z   z y  x, y 
w  x, y, z   w0  x, y 
Teoria 1ª ordem
u
z
v
 y x , y  
z
 x x , y  
11
NOV 2004
 rotationabout y - axis
 rotationabout x - axis
Campo de Deformações
Teoria Clássica Laminados
u
1  w 

x  0   0   z x
x 2  x 
x
2
y
v 0 1  w 0 


y 

z
y 2  y 
y
z  0
v 0 1  w 0 
 2w 0
  z
y 
 
y 2  y 
y 2
z  0
 2w 0
1  u 0 v 0 w 0 w 0 
  2z
 xy  


2  y
x
x y 
xy
1  w 0 w 0 
 xz   

0
2  x
x 
12
2
2
u 0 1  w 0 
 2w 0
x 
 
 z
x 2  x 
x 2
 yz 
Teoria 1ª ordem
1  w 0 w 0 

0

2  y
y 
NOV 2004
2
 u 0 v 0 w 0 w 0   x y 

  z
 xy  



x
x y   y
x 
 y
w 0 

 xz   x 
0
x 


w 0 
  0
 yz   y 

y


Relação Tensão-Extensão  TCL
Teoria Clássica Laminados


0x 
u 1  w0 
 

x 2  x 
0
13
0y 
Extensões superfície
média
u 0 v 0 w0 w0
 


y
x
y x
Curvaturas
 2 w0
x   2
x
Relação
Tensão/Extensão
NOV 2004
v 1  w0 
 

y 2  y 
0
0
xy
i

2
 2 w0
y   2
y
 2 w0
 xy  2
xy
 0x  z  x 
 x 

 
i  0
  y   Q    y  z  y 
 
 0  z  
xy 
 xy 
 xy
2
Leis Constitutivas  TCL
Force per unit length:
  x0 
 N x  t 2  x 
 k x  zk
zk
N
N
 

 
 

i 
i 
N


dz

Q

dz

Q
k
 y   y
 y0  
 y   zdz


k 1
k 1
 N   t 2  
  zk 1
k  zk 1

xy
xy
 
 
 xy 
xy


 0
Moment per unit length:
NOV 2004
Forças de membrana
actuantes no laminado
0 

N
A
B
  
  
 
 
 M   B D    
  x0 
 M x  t 2  x 
 k x  zk
zk
N
N




 


i 
i 
2
 M y      y  zdz   Q   y0   zdz  Q  k y   z dz
k 1
k 1
 M   t 2  
  zk 1
k  zk 1

xy
xy


 
 xy 

 xy0 

14


Momentos actuantes
no laminado
Relação Tensão-Extensão  1ª ordem

Extensões superfície média
v 1  w0 
0y 
 

y 2  y 
w0
0
 xz 
 x
x
u 1  w0 
0x 
 

x 2  x 
0
 0yz 
w
 y
y
0
2
0
u 0 v 0 w0 w0
 


y
x
x y
0
xy

15
Curvaturas
 y
 x
x 
y 
x
x
  y
 xy  x 
 yz   xz  0
y NOV
x 2004
2

Relação Tensão/Extensão
 0x  z  x 
 x 
 0

 
y 
  y  z y 

 

i  0


 xy   Q    xy  z  xy 
 
 0

yz
 yz 


0






 xz 
xz

i
Leis constitutivas  1ª Ordem
Transverse shear
force resultants:
h
Qx 
2

xz
dz
yz
dz
h2
h
Qy 
2

h2
Q x 
 A 44
 
   K

Q y 
 A 45
16
w 0 

A 45  x 
x 
 

   w 0 
A 55  y

y 
NOV 2004
2


u 0 1  w 0 
 x 





 Nx 


x 2  x 



x
 


2


 
v 0 1  w 0 
 y 

 
 N y   A
  B


y
2

y

y


 








N 
 u 0 v 0 w 0 w 0 
 x
y



 xy 

 y  x 
x
x y 


 y

2


u 0 1  w 0 
 x 





 Mx 


x 2  x 



x




2






v 0 1  w 0 


y

 
 M y   B
  D

y 2  y 
y








M 
 u 0 v 0 w 0 w 0 
 x
y





 xy 


 y
x 
x
x y 

 y

Exemplo – Ensaios 3PB

Viga de contraplacado
–

Vigas sandwich faces em GRP núcleo PU
–
17
Comparação entre a TCL e 1ª Ordem
Comparação entre a TCL e 1ª Ordem
NOV 2004
Exemplo – Ensaios 3PB

Deslocamento a meio vão:
PL3 PL
w

48D 4U
Corte
TCL (bending)
1ª Ordem
18
NOV 2004
Viga de contraplacado 18.2 mm

Contraplacado de
madeira de vidoeiro
–
–
–
–
19
13 camadas
[0º,90º,0º...,0º,90º,0º]
Material Ortotrópico
Vão 1000 mm
Resultados Força vs
Deslocamento
NOV 2004
Viga de contraplacado 18.2 mm
1.2
TCL
1
FEM
Força [kN]
CNTPL 18
0.8
0.6
0.4
0.2
0
0
5
10
Deslocamento [mm]
20
NOV 2004
15
20
Viga sandwich em GRP + PU

Viga sandwich
–
Faces em fibra de vidro
em matriz de poliéster


–
Núcleo em espuma de
poliuretano


21
Espessura de 2.5 mm
Gramagem de 900 g/m2
Espessura de 50 mm
Densidade de 40 kg/m3
NOV 2004

Materiais Isotrópicos
–
Faces


–
E = 6100 MPa
 = 0.33
Núcleo


E = 7.5 Mpa
 = 0.33
Vigas sandwich em GRP + PU
4.5
4
3.5
Força (kN)
3
2.5
2
Painel 1-A
Painel 1-B
Painel 3-B
Painel 5-B
TCL
ANA
1.5
1
0.5
Painel 2-A
Painel 2-B
Painel 4-B
Painel 6-B
FEM
0
0
10
20
30
Deslocamento [mm]
22
NOV 2004
40
50
60
Design procedures
Design procedures


24
Vários envelopes de
rotura concorrentes
Altamente dependente
da geometria e do
carregamento
NOV 2004
Design procedures
25
NOV 2004
Design procedures
26
NOV 2004
Design procedures
27
NOV 2004
Aplicações
Aplicações








29
Aeroespacial
Aeronáutico
Construção
Desporto
Naval
Automóvel
Veículos Ferroviários
etc
NOV 2004
Satélites
1 Solar Panels : Epoxy carbon prepregs, aluminum honeycomb,
film adhesive
2 Reflectors Antennae : Epoxy/aramid prepreg, cyanate carbon
prepreg, aramid/aluminum honeycomb
3 Satellite Structures : Carbon prepreg, aluminum honeycomb, film
adhesive
30
NOV 2004
Aeroespacial
1 Fairings: Carbon prepregs. Aluminium
honeycomb and adhesives.
2 External Payload Carrier Assembly (SPELTRA):
Carbon prepregs, aluminium honeycombs and
adhesives.
3 EPS Ring: Epoxy/carbon prepreg or RTM.
4 Front Skirt: Carbon prepreg.
5 Booster Capotage: Epoxy glass/non-metallic
honeycomb.
6 Yoke: Epoxy carbon filament winding.
7 Heat Shield: Carbon prepreg/high temperature
resistant glass fabric.
31
NOV 2004
Aeronautico
32
1 Radar Transparent Radome: Epoxy
or BMI Prepreg or RTM resins and
woven preforms (socks)
6 Wing Skins and Ribs: Epoxy carbon
and glass Prepregs
2 Foreplane Canard Wings: Epoxy
carbon Prepregs
7 Fin Tip: Epoxy/quartz Prepregs
3 Fuselage Panel Sections: Epoxy
carbon Prepregs. Non-metallic
honeycomb core and Redux
adhesives
8 Rudder: Epoxy carbon Prepreg
4 Leading Edge Devices: Epoxy
carbon and glass Prepregs
9 Fin: Epoxy carbon/glass Prepreg
5 Fin Fairings: Epoxy glass and
carbon Prepregs
10 Flying Control Surfaces: Epoxy
carbon and glass Prepregs.
Honeycomb core material and Redux
adhesives
NOV 2004
Pás do rotor de um helicóptero Sea
King, mostrando a estrutura interna em
compósito. Com a aplicação de
compósitos consegue-se maior
velocidade das pás e menor
transmissão de vibrações à estrutura.
33
NOV 2004
Naval
34
1 Decking: Heavy duty structural sandwich panels
9 Weather Shield: Prepregs and honeycombs.
2 Hull Skin Structure: Prepregs, engineered fabrics,
honeycombs.
10 Communications Equipment : Prepregs and
honeycombs.
3 Lightweight Floor Structure: Sandwich panels.
11 Companionway Stairs : Structural sandwich
panels
4 Suspended Ceilings : Lightweight sandwich
panels/honeycombs.
12 Partitions: Lightweight sandwich panels.
5 Interior Furnishings : Lightweight stiff sandwich panels
suitable for fabrication. Prepregs and fabrics.
13 Lightweight Superstructure: Sandwich panels
and Prepregs.
6 Hull Skin Structure: Prepregs, engineered fabrics,
honeycombs.
14 Engine Room : Sandwich panels and special
products for FST and sound attenuation..
7 Accommodation Cabin Units: Lightweight sandwich
panels, Prepregs and honeycombs.
15 Drive Shafts & Couplings: Epoxy Prepregs and
fabrics
8 Bridge Deck Consoles:
Lightweight sandwich panels.
NOV 2004
Naval
35
NOV 2004
Desporto
36
NOV 2004
O quadro (que já nem sequer tem a forma tradicional de
um quadro...) da bicicleta da figura é feito em carbono/
epoxy, bem como as jantes das rodas. Consegue-se
maior rigidez e menor peso em relação às estruturas de
alumínio. Além disso, o design pode e deve ser alterado
para maximizar os benefícios do novo material.
37
NOV 2004
Aplicações diversas de compósitos em artigos de desporto e
lazer. A sua utilização destina-se, em geral, a poupar peso,
ganhando rigidez e resistência e, por vezes, permitindo um
design mais atractivo que as ligas metálicas, devido à facilidade
de moldagem.
38
NOV 2004
Construção civil
39
NOV 2004
Comboios
Sandwich technology:
The sandwich principle has been successfully
used in the marine and aerospace industries.
Now, Bombardier's new Fully Integrated
Carbody Assembly System (FICAS)
revolutionizes manufacturing in the rail
industry.
40
FICAS consists of a thin sandwich construction
comprising a steel skin bonded to a rigid core.
The advantage of this approach to the overall
space saving equation is that the sidewalls
become significantly thinner than a
conventional wall, with possible savings of up
to 120 millimeters in wall thickness. (May
2003)
NOV 2004
Automóvel

With the long version, the A-class sets a new record for compact cars, for no
other automobile in this market segment offers so much cubic capacity, as
much as 68.2 cubic feet – which is 11 percent more than the unchanged
current standard version.

The spatial economy of the new body variant is equally
commendable: since the drive units, thanks to the sandwich
concept, are positioned partly in front of and partly beneath the
passenger cell, 53 percent of the 12 foot 5 inch body is available to
the passengers …
“With the new variant we can now also satisfy prospective customers
who were already convinced by the A-Class design and concept but
wanted to have more room,” emphasized D. Joachim Schmidt,
member of divisional management…

41
NOV 2004
Automóvel

Therefore, American's steel manufacturers hired Porsche Engineering
Services to develop a new kind of steel monocoque technology calls Ultra
Light Steel Auto Body (ULSAB). As shown in the picture, basically it has the
same structure as a conventional monocoque. What it differs from its donor
is in minor details - the use of "Hydroform" parts, sandwich steel and laser
beam welding.

42
Sandwich steel is made from a thermoplastic (polypropylene) core in
between two very thin steel skins. This combination is up to 50
percent lighter compared with a piece of homogenous steel without a
penalty in performance. Because it shows excellent rigidity, it is
applied in areas that call for high bending stiffness. However, it
cannot be used in everywhere because it needs adhesive bonding or
rivetingNOV
instead
of welding.
2004
Transporte Isotérmico

43
Vantagem da construção sandwich:
Alto isolamento térmico aliado ao desempenho estrutural
NOV 2004
Bibliografia
Bibiografia










45
Plantema, F.J., Sandwich construction; the bending and buckling of sandwich beams, plates,
and shells. 1966, New York,: Wiley. xx, 246.
Allen, H.G., Analysis and design of structural sandwich panels. 1st ed. 1969, Oxford New
York: Pergamon. xvi, 283.
Forest Products, L., Wood handbook : wood as an engineering material. General technical
report (Forest Products Laboratory) ; FPL-GTR-113. 1999, Madison: The Laboratory.
Gay, D., Matériaux composites. 4e éd. rev. et augm. ed. Collection Matériaux. 1997, Paris:
Hermès,. 672.
Gibson Lorna, J. and F. Ashby Michael, Cellular solids : structure & properties. International
series on materials science & technology. 1988, Oxford: Pergamon 1988.
Metzger, D.J., The selection of sandwich panels. 1970: Ithaca, N.Y. p. x, 142 l.
Middleton, D.H., Composite materials in aircraft structures. 1990, Harlow: Longman Scientific
& Technical.
Vinson, J.R., The behavior of sandwich structures of isotropic and composite materials. 1999,
Lancaster, Pa.: Technomic Publishing Co.
Zenkert, D., An introduction to sandwich construction. 1997, Warley: Emas.
Zenkert, D. and F. Nordic Industrial, The handbook of sandwich construction. North European
engineering and science conference series. 1997, Cradley Heath: EMAS Publishing.
NOV 2004
FIM