Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 17 of 17 for “"Weibull Modulus"”.
-
Effects of oxide film, Fe-rich phase, porosity and their interactions on tensile properties of cast Al-Si-Mg alloys
… the results analysed by Yate’s algorithm and Weibull statistical analysis to determine their relative effects. The most important defect in this research was the oxide film that had an effect on UTS and elongation of about 21 MPa and 0.9% respectively and on the UTS Weibull modulus and …
-
Tensile and Flexure Strength of Unidirectional Fiber-Reinforced Composites: Direct Numerical Simulations and Analytic Models
… to the ordered composite) with increasing Weibull modulus. A modified Batdorf-type analytic model is developed and similarly extended to the case of non-uniform loading to predict the strength of composites under tension and flexure. The flexure model is found to be inappropriate for …
-
Engineered Alumina / Silicon Carbide Laminated Composites
… and improved mechanical reliability, in terms of Weibull modulus or minimum threshold failure stress, can be achieved by the engineering of the critical surface region in the ceramic component. Such effect can be realized by using a laminated composite structure with tailored sub-surface insertion …
-
Precursor gas comparison for the growth of silicon carbide fibers via laser chemical vapor deposition
… were qualitatively more delicate to handle. A Weibull analysis revealed that the fibers had a low Weibull modulus, which is an indication of a large and unpredictable variation of flaws within the fibers.
-
Tensile and uniaxial/multiaxial fatigue behavior of ceramic matrix composites at ambient and elevated temperatures
… from the tensile strength model suggest that the Weibull modulus, <i>m</i>, of the strength of the reinforcing fibers and the fiber/matrix interfacial shear stress both have significant effect on the strength and toughness of the unidirectional composite: a higher <i>m</i> value and a lower …
-
Optimal design and freeform extrusion fabrication of functionally gradient smart parts
… properties including density, strength, Young's modulus, Weibull modulus, toughness, and hardness were examined. Microstructural evaluation was also performed to measure the grain size, and critical flaw sizes were obtained. The results indicate that the proposed method enables fabrication of …
-
Tensile behavior of unidirectional and cross-ply ceramic matrix composites
… fibers. Resulting characteristic strength and Weibull modulus values combined with measured fiber pullout lengths were then used to determine material parameters such as the ultimate tensile strength, strain to failure, work of pullout, sliding distance at the characteristic strength, and …
-
Structure, property, and processing relationships of CMZP - [(Ca<sub>0.6</sub>,Mg<sub>0.4</sub>)Zr₄(PO₄)₆]
… flexure strength of 124.77 MPa, (2) an elastic modulus of 118.45 GPa, and (3) a Weibull modulus of 10.7. At 850°C, the flexure strength and elastic modulus were 118.35 MPa and 68.63 GPa while at 1050°C they were 89.57 MPa and 78.27 GPa. Samples tested at 1250°C creeped during loading. The …
-
Freeform extrusion fabrication of advanced ceramics and ceramic-based composites
… including density, flexural strength, Young's modulus, Weibull modulus, fracture toughness, and hardness were measured. The results indicated that superior mechanical properties were achieved by the CODE process among all the additive manufacturing processes. Further development was made on the …
-
Microfabricated refractory ceramic structures for micro turbomachinery
… exhibits a reference strength of 724 MPa with a Weibull modulus, m =16.0. This thesis documents the design trades that led to the selection of CVD SiC as the primary candidate refractory material for the microengine, and the initial experiments performed to assess its suitability and guide future …
-
Mechanical and interfacial properties of carbon nanofibers for polymer nanocomposites
… Their nominal tensile strengths followed Weibull distributions with characteristic strength values between 2.74- 3.34 GPa, which correlated well with the expected effects of heat treatment and oxidative post-processing. These values are the first measurements reported for VGCNFs and are …
-
Constraint and Ductile Tearing Effects on the Cleavage Fracture of Ferritic Steel
… steels in terms of KJc (or Jc) values with the Weibull stress model, i.e ., the ""local approach"" for fracture at the micro-scale. The E1921 procedures assume that uniform, small-scale yielding (SSY) conditions exist at fracture along the full crack-front. Plasticity induced constraint loss …
-
Safety of light water reactor fuel with silicon carbide cladding
… model for stress distribution and Weibull statistical fracture of laminated SiC cladding during normal and accident conditions is developed. It is coupled to fuel rod performance code FRAPCON-3.4 (modified here for SiC) and RELAP-5 (to determine coolant conditions). It is concluded …
-
Geopolymer composites and their applications in stress wave mitigation
… and statistical analyses of brittle fractures (Weibull distribution) have been performed to investigate the optimal mechanical strengths of Cf KGP composites. In addition to the static measurements, the Young’s and shear moduli of Cf KGP have been measured by dynamic methods such as impulse …
-
Porosity control of alkali-activated aluminosilicates via functional alkoxysilane additives
… compressive testing found a 48% increase in Weibull modulus for compressive strength and a probable increase in compressive strength. Mercury intrusion porosimetry measurements showed up to a 24% increase in bulk density. Meaningful property modification and mesoporosity reduction required …
-
Studies of structure cracking and fracture strength of E-glass fibres using acoustic emission.
… significant variation in the bundle strength and Weibull parameters. Samples were also tested across the width of the strand and significant variations in these parameters were again found. These results show that it is essential to test a complete strand of filaments for accurate evaluation of …
-
In-situ Fiber Strength Distribution in NextelTM 610 Reinforced Aluminum Composites
MetPreg, a composite developed by Touchstone Research Laboratories (Tridelphia, WV), is an aluminum metal matrix composite reinforced by continuous NextelTM 610 alumina fibers. The question is, after processing, are the NextelTM fibers affected in any way that their strengthening contribution to …