Effect of Fillers on E-Glass/Jute Fiber Reinforced Epoxy Composites
Development of honeycomb sandwich by Zheng Chen
1. Sandwich panel containing Kraft paper honeycomb core
and wood composite skin
Development of Novel Hollow Core Composite Panels for
Value-Added Secondary Applications
By: Zheng Chen,
Faculty of Forestry, University of Toronto
http://www.valuetowood.ca/
Funded by a Value to Wood Program of Natural
Resources Canada
Collaboration with
University of British Columbia
FPInnovations-Forintek in Quebec city
2. System of project
Sample prepare and bending test in UBC
Tests of compression, shear and creep
in FPInnovation-Forintek
Development of finite element (FE) model in UT
3. Kraft paper honeycomb panel
applications in furniture industry
• Excellent strength to weight ratio
• Low material cost
• Smooth skin
• Excellent fatigue resistance
• Excellent crush strength and stiffness
• Structural integrity
• Exceptionally high strengths available
4. Project goal
To characterize the influence of parameters on the
material properties of sandwich panel containing
Kraft paper honeycomb core and wood composite
skins for developing panels with higher ratio of
stiffness to weight
32. Development of FE model
Procedure of model establishment
Using data from Karademir et
al (2004) as Ex and Ey of central
layer of 3D FE model for all types
Of honeycomb core
Obtaining Ez, Gxz and Gyz of
central layer of FE model for
expanded honeycomb core
by fitting the test data from
Advanced Honeycomb
Technologies Inc.(2007)
Using relative data from Youngquist
(1999) for material properties of HB,
MDF and PW skins
Obtaining Ez, Gxz and Gyz of
central layer of FE model for
corrugated and laminated
honeycomb core by fitting the
test data from FPInnovations
(Chen et al 2011)
Obtaining material properties of
central layer for uniform entity
FE model for creep and bookshelf
Prediction the influence of parameters
that the test data did not cover
33. Comparison of FE model predictions and test data
Edgewise compression
34. Comparison of FE model predictions and test data
Edgewise compression
Note: all panels are made from expanded core and MDF skins and have 31.75 mm
cell size.
35. Comparison of FE model predictions and test data
Interlaminar shear loading
36. Comparison of FE model predictions and test data
Interlaminar shear loading
Note: all panels are made from expanded core and MDF skins and have 31.75 mm
cell size.
37. Comparison of FE model predictions and test data
Flexural creep
Primary Secondary Tertiary
Creep measured in
Forintek
Expanded honeycomb
core and HB skin. Sample
span in y direction
Note: loading level for all sample is 54.25 N
38. Comparison of FE model predictions and test data
Flexural creep
Primary Secondary Tertiary
Creep measured in
Forintek
FE model
predictions
Expanded honeycomb
core and HB skin. Sample
span in y direction
These FE model were developed by using the
Nonlinear method and material creep effect (based on
Baily-Newton law) of COSMOSWORK 2008 Advanced
Professional (COSMOSWORK 2008 SP2.1)
Note: loading level for all sample is 54.25 N
39. Comparison of FE model predictions and test data
Flexural creep
Primary Secondary Tertiary
Creep measured in
Forintek
Expanded honeycomb
core and HB skin. Sample
span in y direction
Expanded honeycomb
core and HB skin. Sample
span in x direction
FE model
predictions
FE model
predictions
Note: loading level for all sample is 54.25 N
40. Comparison of FE model predictions and test data
Bookshelf under bending
41. Comparison of FE model predictions and test data
Flexural fatigue
FE model predictions
42. Results
Influence of shelling ratio and cell size
Gxz of pane with
25.4 mm size cell
Note: all panels are made from expanded core and HB skins
43. Results
Influence of shelling ratio and cell size
Gxz of pane with
12.7 mm size cell
Gxz of pane with
25.4 mm size cell
Note: all panels are made from expanded core and HB skins
44. Results
Influence of shelling ratio and cell size
Gxz of pane with
12.7 mm size cell
Gxz of pane with
25.4 mm size cell
Gyz of pane with
25.4 mm size cell
Note: all panels are made from expanded core and HB skins
45. Results
Influence of shelling ratio and cell size
Gxz of pane with
12.7 mm size cell
Gyz of pane with
12.7 mm size cell
Gxz of pane with
25.4 mm size cell
Gyz of pane with
25.4 mm size cell
Note: all panels are made from expanded core and HB skins
46. Results
Influence of shelling ratio and cell size
Pane with 12.7 mm
size cell
Pane with 12.7 mm
size cell
Note: all panels are made from expanded core and HB skins
47. Results
Influence of shelling ratio and cell size
Ex of pane with 12.7
mm size cell
Note: all panels are made from expanded core and HB skins
48. Results
Influence of shelling ratio and cell size
Ex of pane with 12.7
mm size cell
Ex of pane with 25.4
mm size cell
Note: all panels are made from expanded core and HB skins
49. Results
Influence of shelling ratio and cell size
Ex of pane with 12.7
mm size cell
Ex of pane with 25.4
mm size cell
Ey of pane with 25.4
mm size cell
Note: all panels are made from expanded core and HB skins
50. Results
Influence of shelling ratio and cell size
Core cell size
(mm)
Web thickness
(mm)
Ez
(MPa)
Ey
(MPa)
Gyz
(MPa)
Gxy
(MPa)
15.9 0.29 10.06 644.76 4.72 228.55
20.3 0.37 10.07 645.08 4.86 228.64
Note: both panels are made from 26 mm thick expanded core and 3 mm thick HB
skins and have the same core density
51. Results
Influence of shelling ratio and cell size
Core density
(Kg/m3
)
Web thickness
(mm)
Ez
(MPa)
Ex
(MPa)
Gxz
(MPa)
Gxy
(MPa)
11.53 0.15 2.68 642.85 2.81 218.77
22.01 0.29 5.05 644.74 5.31 218.61
Note: both panels are made from 26 mm thick expanded core and 3 mm thick HB
skins and have the same cell size.
52. Results
Influence of shelling ratio and cell size
Aluminium panel. 38 mm cell size,
30 kg/m3
core density,1.2×10-6
kg/mm2
weight
53. Results
Influence of shelling ratio and cell size
38 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
Aluminium panel. 38 mm cell size,
30 kg/m3
core density,1.2×10-6
kg/mm2
weight
55. Results
Influence of shelling ratio and cell size
38 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
32 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
56. Results
Influence of shelling ratio and cell size
38 mm cell size, 15 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
32 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
57. Results
Influence of shelling ratio and cell size
38 mm cell size, 15 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
32 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 8 kg/m3
core
density,1.2×10-6
kg/mm2
weight
58. Results
Influence of shelling ratio and cell size
38 mm cell size, 15 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
32 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 8 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 10 kg/m3
core
density,1.3×10-6
kg/mm2
weight
59. Results
Influence of shelling ratio and cell size
32 mm cell size, 10 kg/m3
core density,1.2×10-6
kg/mm2
weight, longer panel
38 mm cell size, 15 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
32 mm cell size, 10 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 8 kg/m3
core
density,1.2×10-6
kg/mm2
weight
38 mm cell size, 10 kg/m3
core
density,1.3×10-6
kg/mm2
weight
60. Results
Influence of shelling ratio and cell size on flexural creep
Shelling ratio is 2
Shelling ratio is 4
Shelling ratio is 9
Shelling ratio is 12
61. Results
Influence of core structure on the stiffness of
sandwich panel
Core type Ex
(MPa)
Ey
(MPa)
Ez
(MPa)
Gxz
(MPa)
Gyz
(MPa)
Gxy
(MPa)
Expanded
honeycomb
core
644.74 642.98 5.05 5.31 2.52 218.61
Corrugated
honeycomb
core
669.24 641.61 6.67 12.19 1.37 217.92
Note: sandwich panel with 3 mm thick HB skin and 26 mm thick core. All
core densities are 22.01Kg/m3
62. Results
Influence of core structure on the stiffness of
sandwich panel
Core type Ex
(MPa)
Ey
(MPa)
Ez
(MPa)
Gxz
(MPa)
Gyz
(MPa)
Gxy
(MPa)
Expanded
honeycomb
core
644.74 642.98 5.05 5.31 2.52 218.61
Corrugated
honeycomb
core
669.24 641.61 6.67 12.19 1.37 217.92
Note: sandwich panel with 3 mm thick HB skin and 26 mm thick core. All
core densities are 22.01Kg/m3
63. Results
Influence of core structure on the stiffness of
sandwich panel
Type of skin
material
Ez
(MPa)
Ey
(MPa)
Gyz
(MPa)
Gxy
(MPa)
HB 8.05 641.78 4.58 227.46
MDF 8.03 388.88 4.56 137.78
PL 6.57 235.5 3.9 11.7
Note: sandwich panel with 3 mm thick skin and 26 mm thick core. All core densities
are 22.01Kg/m3
64. Results
Influence of core structure on the stiffness of
sandwich panel
Type of skin
material
Ez
(MPa)
Ey
(MPa)
Gyz
(MPa)
Gxy
(MPa)
HB 8.05 641.78 4.58 227.46
MDF 8.03 388.88 4.56 137.78
PL 6.57 235.5 3.9 11.7
Note: Sandwich panel with 3 mm thick skin and 26 mm thick core. All core
densities are 22.01Kg/m3
73. Results
Influence of rail width of shelf on the ratio of
bending force to deflection
Shelf with rail edge
74. Results
Influence of stile width of shelf on the ratio of
bending force to deflection
Shelf with rail edgeShelf with rail edge
Shelf with stile edge
75. Results
Influence of stile and rail width of shelf on the
ratio of bending force to deflection
Shelling ratio is 2.8
76. Results
Influence of stile and rail width of shelf on the
ratio of bending force to deflection
Shelling ratio is 10.7
Shelling ratio is 2.8
77. Results
Primary flexural creep of shelf with different size of
rail under uniform loading
65 mm wide rail
71 mm wide rail
78. Results
Primary flexural creep of shelf with different size of
rail under uniform loading
Note: All panels have 32 mm thick core and 3 mm thick skin
250 mm wide rail
65 mm wide rail
71 mm wide rail
38 mm wide rail
10 mm wide rail
79. Results
Primary flexural creep of shelf with different size of
rail under uniform loading
Note: All panels have 32 mm thick core and 3 mm thick skin
250 mm wide rail
65 mm wide rail
71 mm wide rail
38 mm wide rail
10 mm wide rail
81. Conclusions
• Finite element (FE) models for straight and curved sandwich panels
made from Kraft paper honeycomb core and wood composite skins
were developed for predicting panels’ stiffness under compression,
shear force, flexural loading, creep, fatigue and impact energy. The
predicted Ex. Ey, Ez, Gxz, Gyz and primary flexural creep from the
FE models were in good agreement with the respective experimental
results. The predicted fatigue, impact and bending behavior of
straight and curved sandwich panel from these initial FE models
need to be calibrated by respective experiments.
• The influences of panel’s curve degree, loading direction, core
shape, core cell size, core thickness, skin thickness and skin type on
these behaviors were evaluated using these developed FE models.
Some key points of optimization of these honeycomb core sandwich
panels (e.g. shelling ratio, core shape, core density, core orientation
and cell size, curved degree and orientation, etc) were found
according to these evaluations.
82. Conclusions
• The FE models for bending and creep of bookshelves with edging
supports were developed too. The predictions from these FE
models for sandwich panel four-point bending load were verified
against test results. The influence of edging support size (rail and
stile width) on the bending stiffness of shelf were studied using
these FE models and the results indicated that bending stiffness is
more sensitive to stile edgings of the shelf and shelling ratio than rail
edgings. FE models for shelf under uniform flexural loading and
creep need to be calibrated by further tests and the predicted results
need to be confirmed by further experiments.
83. Acknowledgement
NRCan-Value to wood program for financial support
FPinnovations-Forintek division in Quebec city and
Pof. Greg Smith and his group in the University of
British Columbia and for their cooperation and
assistances
