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Quasi-Static 3-Point Reinforced Carbon-Carbon Bend Test and Analysis for Shuttle Orbiter Wing Leading Edge Impact Damage Thresholds
| Content Provider | Semantic Scholar |
|---|---|
| Author | Fasanella, Edwin L. Sotiris, Kellas |
| Copyright Year | 2006 |
| Abstract | Abstract Static 3-point bend tests of Reinforced Carbon-Carbon (RCC) were conducted to failure to provide data for additional validation of an LS-DYNA RCC model suitable for predicting the threshold of impact damage to shuttle orbiter wing leading-edge panels. LS-DYNA predictions correlated well with the average RCC failure load, and showed good agreement in matching the load versus deflection response. However, correlating the detectable damage using nondestructive evaluation (NDE) methods with the cumulative damage parameter in LS-DYNA material model Mat58 was not readily achievable. The difficulty of finding internal RCC damage with NDE and the high sensitivity of the Mat58 damage parameter to the load near failure made the task very challenging. In addition, damage mechanisms for RCC due to dynamic impact of debris such as foam and ice are not equivalent to damage mechanisms due to a static loading. Background The criterion defining impact damage threshold of the wing leading edge panels used by the Orbiter Project was changed from a through crack to internally detectable nondestructive evaluation (NDE) damage plus some outer silicon carbide (SiC) coating loss. This change presented a challenge to the existing shell model of shuttle orbiter Reinforced Carbon-Carbon (RCC) since delamination and coating loss cannot be directly represented in a shell element. Consequently, simple static 3-point RCC bend tests were proposed by the NASA Engineering and Safety Center (NESC) as a useful test in addition to ballistic testing to assist in calibrating the LS-DYNA RCC material model for predicting internal RCC damage caused by debris impacts. The tests could also serve as a “level 1” validation test for RCC material. Since the test was quasi-static, loads and displacements could be accurately measured experimentally. However, static and dynamic damage and failure mechanisms are often very different. Static tests allow the entire structure to move without inertial loading effects. Thus, the forces are more global and the internal stresses more distributed. Dynamic loads are rapidly applied and produce shock effects with complex stress waves. Inertial effects become extremely important. Also, strain-rate effects must be considered, and the dynamic stresses are both much higher and localized near the area of contact. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20060048164.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
