Do thermal residual stresses contribute to the improved fracture toughness of carbon nanotube/alumina nanocomposites?

2012 ◽  
Vol 66 (6) ◽  
pp. 347-350 ◽  
Author(s):  
Yao Chen ◽  
Kantesh Balani ◽  
Arvind Agarwal
Keyword(s):  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Residual Stresses ◽  
Thermal Residual Stresses

Effect of far-field stresses and residual stresses incorporation in predicting fracture toughness of carbon nanotube reinforced yttria stabilized zirconia

2017 ◽  
Vol 122 (14) ◽  
pp. 145104 ◽  
Author(s):  
Neelima Mahato ◽  
Ambreen Nisar ◽  
Pratyasha Mohapatra ◽  
Siddharth Rawat ◽  
S. Ariharan ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Residual Stresses ◽  
Yttria Stabilized Zirconia ◽  
Far Field ◽  
Stabilized Zirconia

Micro-indentation method for evaluation of fracture toughness and thermal residual stresses of SiC coating on carbon/carbon composite

2003 ◽  
Vol 12 (2-3) ◽  
pp. 155-169 ◽  
Author(s):  
Hiroshi Hatta ◽  
Masayuki Mizoguchi ◽  
Masashi Koyama ◽  
Yuko Furukawa ◽  
Toshio Sugibayashi
Keyword(s):  
Fracture Toughness ◽  
Residual Stresses ◽  
Carbon Composite ◽  
Indentation Method ◽  
Thermal Residual Stresses ◽  
Micro Indentation

Modeling of electromechanical response and fracture resistance of multilayer piezoelectric energy harvester with residual stresses

2020 ◽  
Vol 31 (19) ◽  
pp. 2261-2287
Author(s):  
Zdeněk Machů ◽  
Oldřich Ševeček ◽  
Zdeněk Hadaš ◽  
Michal Kotoul
Keyword(s):  
Fracture Toughness ◽  
Residual Stresses ◽  
Fracture Resistance ◽  
Energy Harvester ◽  
Beam Theory ◽  
Vibration Energy Harvester ◽  
Layered Architecture ◽  
Thermal Residual Stresses ◽  
Apparent Fracture Toughness ◽  
Piezoelectric Energy

The article focuses on a modeling and subsequent optimization of a novel layered architecture of the vibration piezoceramic energy harvester composed of ZrO2/Al2O3/BaTiO3 layers and containing thermal residual stresses. The developed analytical/numerical model allows to determine the complete electromechanical response and the apparent fracture toughness of the multilayer vibration energy harvester, upon consideration of thermal residual stresses and time-harmonic kinematic excitation. The derived model uses the Euler–Bernoulli beam theory, Hamilton’s variational principle, and a classical laminate theory to determine the first natural frequency, steady-state electromechanical response of the beam upon harmonic vibrations, and also the mechanical stresses within particular layers of the harvester. The laminate apparent fracture toughness is computed by means of the weight function approach. A crucial point is the further optimization of the layered architecture from both the electromechanical response and the fracture resistance point of view. Maximal allowable excitation acceleration of the harvester upon which the piezoelectric layer will not fail is determined. It makes possible to better use the harvester’s capabilities in a given application and simultaneously guarantee its safe operation. Outputs of the derived analytical model were validated with finite element method simulations and available experimental results, and a good agreement between all approaches was obtained.

Fracture Toughness of Highly Ordered Carbon Nanotube/Alumina Nanocomposites

2004 ◽  
Vol 126 (3) ◽  
pp. 238-244 ◽  
Author(s):  
Z. Xia ◽  
W. A. Curtin ◽  
B. W. Sheldon
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Residual Stresses ◽  
Cohesive Zone ◽  
Matrix Cracking ◽  
Frictional Stress ◽  
High Toughness ◽  
Alumina Composites ◽  
Bridging Law

The fracture toughness of highly-ordered multi-wall carbon-nanotube-reinforced alumina composites is calculated from experimental data on nanoindentation cracking. A combined analytical and numerical model, using cohesive zone models for both matrix cracking and nanotube crack bridging and accounting for residual stresses, is developed to interpret the indentation results and evaluate the fracture toughness of the composite. Results show that residual stress and nanotube bridging play important roles in the nanocomposite fracture. The contribution to toughness from the nanotube bridging for cracking transverse to the axis of the nanotubes is calculated to be ∼5 MPa-m1/2. From the nanotube bridging law, the nanotube strength and interfacial frictional stress are also estimated and range from 15–25 GPa and 40–200 MPa, respectively. These preliminary results demonstrate that nanotube-reinforced ceramics can exhibit the interfacial debonding/sliding and nanotube bridging necessary to induce nanoscale toughening, and suggest the feasibility of engineering residual stresses, nanotube structure, and composite geometry to obtain high-toughness nanocomposites.

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