Brazed Titanium Panels
Alloys: Beta 21S, Ti3AI2.5V, Ti6AI4V, TICP
Brazing Alloys: TiCuni, NiCu
Applications: engines nacelles, control surfaces, wing panels, air vehicle platforms
Brazed Inconel and Stainless Steel Panels
Alloys: Inco 617, 625, 718, Stainless 304, 316, 321, 15-7 ph
Brazing Alloys: AMS 4777, BNi-5A, and others
Applications: nacelle, heat shields
Bonded Stainless Panels
Alloys: 304, 316, 321, 15-7 ph
Applications: Naval doors, Bulkheads, Transit floor panels
Graphite / Titanium Honeycomb
Titanium honeycomb core advantages
in graphite bonded structures
- Low structural weight fraction (compared to stiffened or monolithic skins)
- High stiffness / panel stability / flutter resistance
- Robust designs (carries loads after high impact)
- Simplified construction (reduced fasteners / part count) equals lower assembly cost
- Impact damage easily detected and repaired
- Eliminates corrosion issues of aluminum
- Fluid intrusion / leakage can be eliminated
- Laser welded nodes & square cell yield high shear strength (with balanced L&T properties) and extremely high compressive strengths
- Broad design latitude (few restrictions)
- Ability to tailor cell size / density for optimum design
- Galvantic and thermal compatibility with graphite
- Compatible with BMI resins
- Higher temperature capability
- GR/Epoxy Laminates - 250F hot/wet
- GR/BMI Laminates - 350F hot/wet
- GR/PMR Laminates - 600F
Benecor titanium surface preparation process enhances panel bond strengths
| Impact damage modes by skin design: |
Damage modes: |
 |
Impact side - very visible (local damage)
Internal - core crushing (no disbonds)
Back side - no damage |
 |
Impact side - barely visible
Internal - foam crushing & disbond
Back side - no visible damage |
 |
Impact side - barely visible
Internal - delaminations
Back side - no visible damage |
Impact damage relationship
| Ti-Core Sandwich |
Monolithic (Solid GR/EP Laminate) |
 |
 |
20 CM2 damage area confined to the core crush -
no delamination of graphite skins |
1020 CM2 damage area damage
mechanism ply delamination |
| |
|
Graphite / Titanium -
3 point bend coupon |
Graphite / Titanium
Spar - Fuselage Structure |
 |
 |
| Failure in honeycomb -
no delamination of graphite |
|
| |
|
Graphite / Titanium
Spar - Fuselage Structure |
|
 |
|
Titanium Honeycomb Corrosion Resistance
SO2 / Salt Spray Exposure at Impact Site - Graphite / Epoxy Laminates
