Characteristics of Closed Cell Aluminum Foams „ „ „ „ „ „ „ „ „ Efficient energy absorption Excellent stiffness-to-weight ratio Nearly isotropic - Multiaxial loading Low thermal conductivity Fire resistant Shock wave attenuation Sound and vibration damping and absorption Tailorable density and properties Recyclable Production Process for Aluminum Foam Parts Mixing Press Extrusion press F Al - Powder (Alloys) +TiH2 - Powder CIP Foamable precursor Mold Heating Foaming T ~ 700 °C Aluminum foam 3-D-part Al Foams: Flat plates and 3-D shapes for cores in lightweight aluminum castings Quasi-Static Behavior of Aluminum Foam 60 ρ0 ρ0 ρ0 ρ0 Engineering Stress, MPa 50 = = = = 7 gm gm gm gm /c c /c c /c c /c c 40 30 20 10 0 E n g in e e r in g S t r a in Aluminum Foam Filled 304SS Tubes After Axial Compression 3-D molded foam shape for auto crash energy absorption Aluminum foam insert used for stiffening and energy absorption in auto side rail Tailorability of Aluminum Foams 50 10 σ [MPa] 0.5 Density (g/cm ) 1.0 Plateau stress of Al-12Si foams as a function of foam density Tailorability of Aluminum Foams E [GPa] 50 10 0.5 0.1 1.0 Relative density Elastic modulus of Al-12Si foams as a function of density Aluminum Foam Used in Hybrid Vehicle Armor Alumina Ceramic Aluminum Foam Fiber reinforced polymer Cross-section through lightweight armor using aluminum foam layer, after 20 mm FSP ballistic testing for the U.S Army Aluminum foam impedance layer provides: • Improved defeat of projectile • Enhanced ballistic shock wave attenuation • Lower dynamic deflection of backplate As-fabricated AFS Panel 6082 face sheets mm thick 10 mm AlSi6Cu6 foam core – 30 mm Face sheet diffusio diffusio zone n nzone Diffusion zone Optical micrographs of polished cross section AFS heavy plates Aluminum Foam Sandwich Panels „ „ „ „ Current AFS panels size: 1350 x 1700 x to 80 mm thick (53 x 67 x 0.35 to 3.15 in thick) AFS panel size to be available during 4th Qtr 2007: 1350 x 2500 x to 100 mm thick (53 x 98 x 0.35 to in thick) AFS panel sizes to be available during 1st Qtr 2008: 1500 x 3000 x to 40 mm thick (59 x 118 x 0.35 to 1.6 in thick) and 1500 x 2500 x 40 to 100 mm thick (59 x 98 x 1.6 to in thick) Aluminum Foam Sandwich Panels „ Aluminum alloy face sheet thickness: 0.6 to 20 mm (0.025 to 0.8 in.) „ Aluminum alloy foam core thickness: to 100 mm (0.32 to in.) AFS Panel Face Sheet Alloys „ „ „ „ „ „ „ Al 1050 Al 3103 Al 5005 Al 5083 Al 5754 Al 6060 Al 6082 Al99.5 AlMn1 AlMg1 AlMg4.5Mn AlMg3 AlMgSi0.5 AlMgSi1 AFS Panel Foam Core Alloys „ AlSi7 „ AlSi12 „ AlSiMg „ AlSi6Cux, where x = 4, 6, 10% Specific Bending Stiffness of Aluminum Foam Sandwich Panels Specific Bending Stiffness vs Panel Height 80 70 Spec Bending Stiffness, (N mm /kg *10 ) 90 ⎞ ⎡ td2 ⎤ Ek ∗ td2 ⎛ h ⎜ − 2⎟ ⎢( h − t d ) + ⎥ + 3⎦ ⎝ td ⎠ ⎣ ⎡ ⎞⎤ ⎛ h ⎢ ρd + ρk ⎜ − 1⎟⎥ ⎝ 2td ⎠⎦ ⎣ E∗ I = m Ed 60 ⎡ Nmm ⎤ ⎢ ⎥ ⎣ kg ⎦ AFS Faces t=1mm Foam density 0.3 50 40 Steel 30 I * E E∗ h Aluminum = 12 ρ m 20 ⎡ Nmm ⎤ ⎢ ⎥ ⎣ kg ⎦ 10 Height, h (mm) 10 11 12 13 14 15 Calculated Weight Savings Using Aluminum Foam Sandwich Panels for Equivalent Stiffness Weight Savings Using AFS Panels Panel Type Weight AFS Weight % Weight Savings 11 gage steel 46.39 13.42 71 % 14 gage steel 28.99 11.09 62 % 18 gage steel 20.73 9.96 52 % Extruded Al Channel 10.64 6.26 41 % Vibration damping of AFS vs Steel and aluminum 1.6 Aluminum Foam Sandwich 1.4 Density 0.9 g/cm 1.2 Damping, (%) Spec bending stiffness 41.5 [10 N mm /kg] 0.8 Steel 0.6 Density 7.85 g/cm Spec bending stiffness 0.21 [10 N mm /kg] 0.4 Aluminum 0.2 Density 2.7 g/cm 0 Spec bending stiffness [10 N mm /kg] 100 200 300 Frequency, (Hz) 400 500 600 Joining Methods for AFS Panels „ Welding of cover sheets „ Bolts and screws „ Rivets „ Adhesive bonding MIG Welding of AFS-Beam MIG Welding Welding of AFS Cube 500x500x500 AFS 0,75/13,5/0,75 Core density 0,28 g/cm3 AFS panels can be formed after foaming to produce closed edges | c Life cycle tests of AFS truck crane boom Cyclic multiaxial loading 100 kN (vertical) 14 kN (sideways) ⊥ Req N=40,000 Result: No cracks after more than N=100,000 cycles : Potential Defense Applications ƒ High energy absorption ƒ Very high specific stiffness ƒ Blast mitigation ƒ Electromagnetic shielding ƒ Vibration damping ƒ Fire resistant ƒ Recyclable Alulight produces foam panels and 3-D parts as well as semi-finished components to customer requirements… … as demanded by specific threats [...]... foam Back steel plate - 1/4 in thick Compressive plastic deformation and fracture of aluminum foam exposed to 1 kg PETN explosive at 0.1 m standoff Aluminum experienced up to 70-80% compressive strain in local regions under 1/8 in thick steel front cover sheet Aluminum Foam Sandwich Panels „ Low-density Al alloy closed cell foam cores „ Al foam cores metallurgically bonded to Al alloy face sheets „... kg PETN Standoff distance Blast Test Results „ 2 meter No noticeable damage to foam or steel „ 0.5 meter 50% deformation of foam No back plate deflection „ 0.1 meter 60-80% deformation and fracture of foam Steel plates deformed but not perforated Blast test panels after exposure to detonation of 1 kg PETN at 0.1 m standoff distance Left: Center: Right: Front steel sheet – 1/8 in thick Aluminum foam... Time (ms) 200 250 Damping factor (decay) of 25 mm Al foam panel vs 3 mm and 5 mm Al sheets 3 mm Al-sheet; Weight:1,9 kg 5 mm Al-Sheet; Weight: 3,3 kg 25 mm Al-Foam panel; Weight: 2 kg Decay - Damping factor Eta (-) 1,4E-02 1,2E-02 1,0E-02 8,0E-03 6,0E-03 4,0E-03 2,0E-03 0,0E-03 0 500 1000 1500 Frequency (Hz) 2000 2500 Aluminum Foam Blast Testing Blast Loading of Aluminum Foam Panels Test Configuration... 12 13 14 15 Calculated Weight Savings Using Aluminum Foam Sandwich Panels for Equivalent Stiffness Weight Savings Using AFS Panels Panel Type Weight AFS Weight % Weight Savings 11 gage steel 46.39 13.42 71 % 14 gage steel 28.99 11.09 62 % 18 gage steel 20.73 9.96 52 % Extruded Al Channel 10.64 6.26 41 % Vibration damping of AFS vs Steel and aluminum 1.6 Aluminum Foam Sandwich 1.4 3 Density 0.9 g/cm... 48 x 96 x 0.35 to 4 inch thick Aluminum Foam Sandwich panels in various thicknesses Unfoamed AFS precursor sheets 3100 x 1100 x 2.5 mm AFS AFS plate 1000x1000x30 ±0,5 As-fabricated AFS Panel 6082 face sheets 2 mm thick 10 mm AlSi6Cu6 foam core – 30 mm Face sheet diffusio diffusio zone n nzone Diffusion zone Optical micrographs of polished cross section AFS heavy plates Aluminum Foam Sandwich Panels... during 1st Qtr 2008: 1500 x 3000 x 9 to 40 mm thick (59 x 118 x 0.35 to 1.6 in thick) and 1500 x 2500 x 40 to 100 mm thick (59 x 98 x 1.6 to 4 in thick) Aluminum Foam Sandwich Panels „ Aluminum alloy face sheet thickness: 0.6 to 20 mm (0.025 to 0.8 in.) „ Aluminum alloy foam core thickness: 8 to 100 mm (0.32 to 4 in.) AFS Panel Face Sheet Alloys „ „ „ „ „ „ „ Al 1050 Al 3103 Al 5005 Al 5083 Al 5754 Al... 4, 6, 10% Specific Bending Stiffness of Aluminum Foam Sandwich Panels Specific Bending Stiffness vs Panel Height 80 70 3 4 Spec Bending Stiffness, (N mm /kg *10 ) 90 ⎞ ⎡ td2 ⎤ Ek ∗ td2 ⎛ h 2 ⎜ − 2⎟ ⎢( h − t d ) + ⎥ + 3⎦ 6 ⎝ td ⎠ ⎣ ⎡ ⎞⎤ ⎛ h 4 ⎢ ρd + ρk ⎜ − 1⎟⎥ ⎝ 2td ⎠⎦ ⎣ 3 E∗ I = m Ed 60 ⎡ Nmm 3 ⎤ ⎢ ⎥ ⎣ kg ⎦ AFS Faces t=1mm Foam density 0.3 50 40 Steel 30 I * E E∗ h Aluminum = 12 ρ m 2 20 ⎡ Nmm 3 ⎤ ⎢.. .Aluminum Foam Frame for Ballistic Stress Wave Management External Aluminum Foam Frame Offset Impact Force measurements for shots 13-16 Without Al Foam vs With Al Foam Location 2 Location 3 0 0 -5 -5 3 Force(Kilo-Lb) Force(Kilo-Lb) -10 -15 -20 -25... bending stiffness 41.5 [10 N mm /kg] 1 0.8 Steel 3 0.6 Density 7.85 g/cm 4 3 Spec bending stiffness 0.21 [10 N mm /kg] 0.4 Aluminum 0.2 3 Density 2.7 g/cm 4 0 0 3 Spec bending stiffness 2 5 [10 N mm /kg] 100 200 300 Frequency, (Hz) 400 500 600 Joining Methods for AFS Panels „ Welding of cover sheets „ Bolts and screws „ Rivets „ Adhesive bonding ... -10 -15 2 -20 No Al foam No Al foam With Al foam With Al foam -30 -35 0 0.2 0.4 0.6 0.8 Time (ms) 1 1.2 No AL foam No AL foam With AL foam With AL foam -25 -30 0 0.2 0.4 0.6 0.8 Time (ms) 1 1.2 External Aluminum Foam Frame - Center Impact Acceleration Measurements Without Al Foam vs With Al Foam 3TEX-4A- 2 W ithout AL foa m 12 12 10 10 Shot 2 6 4 2 0 6 4 2 0 -2 -2 -4 -4 -6 -6 -8 0 2 4 6 Time (ms ) Shot