The mechanics and physics of thin film decohesion and its ...
Tokyo Institute of Technology School of Materials and Chemical … · 2016. 12. 6. · •With...
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• With higher discharge voltage, • decohesion between the skin plate and the core resin of the composite panel was observed beneath the stud projection after the test • 1 st stage peak appeared on the load-stroke curve after the elastic region. Tensile test / Interruption test Tokyo Institute of Technology School of Materials and Chemical Technology Kumai-Muraishi laboratory High-speed solid-state joining of aluminum alloy stud on aluminum-resin composite panel 10mm 10mm Ref. STAB GROUP http://stab-group.com Metal-resin composite panel • Lightweight • Good appearance, rigidity, smoothness • Various properties by combinations of skin and core material High-speed solid-state stud joining -- High-density discharge current runs though the contact point of the stud and the panel. • Materials • A2024-T3 stud • 4mm thick composite panel Skin – 0.5mm A3105-H14 Core – 3mm polyethylene resin • Discharge voltage: 270 - 300V (4 cond.) • Applied pressure: 0.2MPa Results Conclusions 1. High-speed solid-state joining of aluminum alloy stud on aluminum- resin composite panel was achieved. 2. The deformation of the crystal grain of the stud was hastened by higher discharge voltage and larger amount of heat input . Joining was achieved where this deformation occurred. 3. Heat produced by this joining method might have affected the strength of the adhesive layer joining the skin plate and the core resin of the composite panel. Further investigation is required to confirm this supposition. Short welding time Low amount of heat input Deformation or melting of the panel can be suppressed Currently, for the installation mechanical method is used ... Ordinary welding method degrades the panel by its large amount of heat input Observation of the joined area Applying High-speed solid-state joining method for the installation to achieve metallurgical bonding * The welding machine was developed by Akebono Kikai Ltd. Decohesion of the composite panel 1mm 300V • Joining was obtained only on the outer side of the stud projection. Deformation of the crystal grain of the stud Joined area Thinning of the skin plate of the panel ... increased with higher discharge voltage . = larger amount of heat input • Decohesion of the skin plate and core resin outside the projection tip was observed after the joining process. This decohesion did not occur if only air pressure was applied (i.e. no discharge current was introduced) • Softening of the skin plate (occurred by Joule heat) observed not only on the plate surface . • When the fracture test was performed on the composite panel before the joining process , the adhesion between the skin plate and the resin core never failed before breaking of the resin core base material . Decohesion occurred No fracture of the joint The joining of the stud and the panel is stronger than the composition panel structure after the joining Objective of the present study 280V 290V Discharge current Air pressure Background Experimental 270V Skin plate Core Resin Adhesive 200μm 0 100 200 300 400 500 600 700 800 900 0 1 2 3 4 5 Tensile load / N Stroke / mm 1 st stage peak 1mm decohesion 270V Skin plate Adhesive Core resin decohesion 290 V 1m m 300V 200μm 200μm 200μm decohesion 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 1 2 52 50 3 57 58 61 54 55 56 60 59 56 61 57 59 58 62 61 61 59 60 4 58 61 62 55 51 61 58 60 63 62 61 63 59 63 56 58 57 60 61 59 62 63 5 54 59 55 44 56 57 59 65 66 60 57 61 65 61 59 61 60 60 57 58 60 63 60 51 59 6 56 49 62 63 70 62 65 64 60 60 63 7 58 61 62 65 64 8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 1 2 72 55 53 41 49 60 64 57 62 60 59 3 67 67 68 55 54 40 57 40 64 58 50 64 62 67 4 68 62 64 65 67 66 62 59 57 58 52 54 55 59 60 62 65 62 58 5 63 67 64 64 63 62 62 55 59 57 56 50 56 59 60 66 6 63 67 63 65 60 54 52 53 55 51 7 62 63 56 62 58 55 54 57 55 8 61 58 59 60 57 48 No discharge current applied • Joule heat is likely to have transferred to the adhesive layer of the composite panel. • The strength of the adhesive joining the skin plate and the core resin might have affected by heat. (Vickers hardness, measurement interval of 120μm) • After the interruption test at the 1 st stage peak...
Transcript of Tokyo Institute of Technology School of Materials and Chemical … · 2016. 12. 6. · •With...
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• With higher discharge voltage,• decohesion between the skin plate and the core resin of the
composite panel was observed beneath the stud projectionafter the test
• 1st stage peak appearedon the load-stroke curveafter the elastic region.
Tensile test / Interruption test
Tokyo Institute of Technology School of Materials and Chemical TechnologyKumai-Muraishi laboratory
High-speed solid-state joining of aluminum alloy stud on aluminum-resin composite panel
10mm10mm
Ref. STAB GROUPhttp://stab-group.com
Metal-resin composite panel• Lightweight• Good appearance, rigidity,
smoothness• Various properties by
combinations of skin and core material
High-speed solid-state stud joining-- High-density discharge currentruns though the contact point of the stud and the panel.
• Materials• A2024-T3 stud• 4mm thick composite panel
Skin – 0.5mm A3105-H14Core – 3mm polyethylene resin
• Discharge voltage: 270 - 300V (4 cond.)• Applied pressure: 0.2MPa
Results
Conclusions
1. High-speed solid-state joining of aluminum alloy stud on aluminum-resin composite panel was achieved.
2. The deformation of the crystal grain of the stud was hastened by higher discharge voltage and larger amount of heat input. Joining was achieved where this deformation occurred.
3. Heat produced by this joining method might have affected the strength of the adhesive layer joining the skin plate and the core resin of the composite panel. Further investigation is required to confirm this supposition.
Short welding time Low amount of heat inputDeformation or melting of the
panel can be suppressedCurrently, for the installation mechanical method is used
... Ordinary welding methoddegrades the panel by its large amount of heat input
Observation of the joined area
Applying High-speed solid-state joining method for the installation to achieve metallurgical bonding * The welding machine was developed
by Akebono Kikai Ltd.
Decohesion of the composite panel
1mm
300V
• Joining was obtained only on the outer side of the stud projection. Deformation of the crystal grain of the stud Joined area Thinning of the skin plate of the panel
... increased with higher discharge voltage.= larger amount of heat input
• Decohesion of the skin plate and core resin outside the projection tip was observed after the joining process. This decohesion did not occur if only air pressure was applied (i.e. no discharge current was introduced)
• Softening of the skin plate (occurred by Joule heat) observed not only on the plate surface.
• When the fracture test was performed on the composite panel before the joining process, the adhesion between the skin plate and the resin core never failed before breaking of the resin core base material.
Decohesion occurred No fracture of the joint
The joining of the stud and the panel is strongerthan the composition panel structure after the joining
Objective of the present study
280V
290V
Discharge current
Air pressure
Background Experimental
270V
Skin plate
Core Resin
Adhesive
200μm
0100200300400500600700800900
0 1 2 3 4 5
Ten
sile
load
/ N
Stroke / mm
1st stage peak
1mm decohesion
270V
Skin plateAdhesiveCore resindecohesion
290V
1mm
300V
200μm200μm
200μm
decohesion
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
1
2 52 50
3 57 58 61 54 55 56 60 59 56 61 57 59 58 62 61 61 59 60
4 58 61 62 55 51 61 58 60 63 62 61 63 59 63 56 58 57 60 61 59 62 63
5 54 59 55 44 56 57 59 65 66 60 57 61 65 61 59 61 60 60 57 58 60 63 60 51 59
6 56 49 62 63 70 62 65 64 60 60 63
7 58 61 62 65 64
8
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
1
2 72 55 53 41 49 60 64 57 62 60 59
3 67 67 68 55 54 40 57 40 64 58 50 64 62 67
4 68 62 64 65 67 66 62 59 57 58 52 54 55 59 60 62 65 62 58
5 63 67 64 64 63 62 62 55 59 57 56 50 56 59 60 66
6 63 67 63 65 60 54 52 53 55 51
7 62 63 56 62 58 55 54 57 55
8 61 58 59 60 57 48
No discharge current applied
• Joule heat is likely to have transferred to the adhesive layer of the composite panel.
• The strength of the adhesive joining the skin plate and the core resin might have affected by heat.
(Vickers hardness, measurement interval of 120μm)
• After the interruption test at the 1st stage peak...
