Quantification of Foreign Object Damage and Electrical Resistivity for Ceramic Matrix Composites and Tensile Residual Strength Prediction

Author(s):  
Frank Abdi ◽  
Gregory N. Morscher ◽  
Yibin Xue ◽  
Sung Choi

SiC-based ceramic matrix composites (CMC) in turbine engine applications must sustain certain foreign object impacts (FOIs) that might occur in services. Experiments and nondestructive evaluation (NDE) have illustrated good correlations between impact energy and foreign object damage (FOD) assessed using electrical resistivity (ER), acoustic emission (AE), and microscopy. A progressive failure dynamic analysis (PFDA) method is explored in understanding and predicting the damage states, ER, and residual strength after impact of CMCs. To accurately correlate the damage state with ER, the PFDA tool has been improved to incorporate the physical damage mechanisms in CMCs, which are matrix microcrack density due to both longitudinal and transverse tensile loads and the fiber breakage due to probabilistic fiber strength distribution. The predicted damage states and ER are correlated with the measurement of FOD and validated with tension after impact tests using high temperature ER. The PFDA tool has demonstrated a great potential for CMCs' FOD and residual strength predictions.

Author(s):  
Frank Abdi ◽  
Yibin Xue ◽  
Gregory N. Morscher ◽  
Sung Choi

SiC-based ceramic matrix composites (CMC) in turbine engine applications must sustain certain foreign object impacts that might occur in services. Experiments and nondestructive evaluation (NDE) have illustrated good correlations between impact energy and foreign object damage (FOD) assessed using electrical resistivity (ER), acoustic emission (AE), and microscopy. In this paper, a progressive failure dynamic analysis (PFDA) method is explored in understanding and predicting the damage states, electrical resistivity, and residual strength after impact of CMCs. In general, CMCs are modeled using effective fiber, matrix, and interface constitutive behaviors, from which the lamina stiffness and strengths can be derived. Similarly, the electrical resistivity of a lamina is homogenized based on the percolation theory for inclusion/discontinuities dispersion in a matrix for voids and Si particles, as well as fibers, and damages after impact. To accurately correlate the damage state with ER, the PFA tool has been improved to incorporate the physical damage mechanisms in CMCs, which are matrix microcrack density due to both longitudinal and transverse tensile loads and the fiber breakage due to probabilistic fiber strength distribution. The predicted damage states and ER are correlated with the measurement of FOD and validated with tension after impact tests using high temperature ER. The PFDA tool has demonstrated a great potential for CMCs’ FOD and residual strength predictions.


2019 ◽  
Vol 45 (2) ◽  
pp. 2635-2643 ◽  
Author(s):  
Michael J. Presby ◽  
Rabih Mansour ◽  
K. Manigandan ◽  
Gregory N. Morscher ◽  
Frank Abdi ◽  
...  

Author(s):  
Sung R. Choi ◽  
D. Calvin Faucett

The combined effects of CMAS (calcium magnesium aluminosilicate) and FOD (foreign object damage) were determined in three different ceramic matrix composites (CMCs), two melt-infiltrated (MI) SiC/SiCs and one oxide/oxide. Foreign object damage was introduced at ambient temperature in CMC test targets using 1.6 mm steel ball projectiles at an impact velocity of 340 m/s utilizing a ballistic impact gun. One type of target support, partial support, was used. The impact-damaged test coupons were then CMAS-exposed at 1200°C for 10 hrs in air. Additional tests were also performed by exposing impact-damaged test coupons to a mixture of CMAS and salt (sodium sulfate) at 1200°C for 10 hrs in air. The combined effects of FOD and CMAS or CMAS/salt were quantified by determining the residual strengths of test coupons after exposures. Also, six different sands ingested into aeroengines were analyzed in their chemical compositions. The melt CMAS solid, melted at 1300°C and solidified, was assessed in its mechanical properties of microhardness and fracture toughness.


Author(s):  
Craig Iwano ◽  
Brian Sullivan ◽  
Michelle Hoo Fatt

Under a Phase II Navy SBIR program, Materials Research & Design (MR&D) performed an integrated analytical, fabrication and experimental program in order to develop foreign object damage (FOD) resistant silicon carbide (SiC) fiber-based ceramic matrix composites (CMCs), specifically 2D tape SiC/SiC. MR&D believes strongly that the most efficient approach towards the development of FOD-resistant CMCs is to develop a mathematical simulation of the impact event which can be correlated to measured responses and observed failures. Once correlated with available test data, the developed math model was used as part of an Integrated Computational Materials Engineering (ICME) approach to analytically investigate modifications to baseline CMC material in an attempt to identify which properties best influenced FOD resistance. The best candidate material modifications were then selected for fabrication and experimental validation. When considering all of the numerical and empirical data (visible damage, rebound velocity (energy absorption), strain data, NDE inspection and residual strength testing), all of the MR&D-proposed material modifications demonstrated improved FOD resistance when compared to the baseline CMC material.


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