Time and Temperature Dependent Stress-Strain Behavior of Unidirectional Carbon Fiber/Polyimide Composites Under On-axis and Off-axis Tensile Loading

Phenomenological constitutive modeling of Ti-6Al-4V at temperatures between 923 and 1023 K under 0.0005–0.05 s−1 quasi-static rates is studied based on a phenomenological approach. For this purpose, the Johnson–Cook constitutive model is revisited. At low temperature conditions under moderate to high strain rates, the material’s stress–strain curves are the most similar to power-law function. Contrary to this, at high temperature conditions under low to moderate strain rates, the saturation-type function well describes the stress–strain curves. On the other hand, it is illustrated that the Johnson–Cook constitutive model is feeble to predict the material’s behavior correctly. Accordingly, in this study, a viscoplastic temperature-dependent constitutive model is developed. The strain rate hardening as well as thermal softening of the developed model is the same as the Johnson–Cook model. But a temperature-dependent strain hardening function is proposed in which both the saturation-type and power-law hardening behaviors of the material are implemented. In comparison with the Johnson–Cook model, the new constitutive model’s fidelity in capturing the titanium behavior is depicted. At last, by considering an Arrhenius-type phenomenological constitutive model, it is noted that the developed constitutive model has the best correctness in predicting the Ti-6Al-4V stress–strain behavior at high temperature conditions under quasi-static rates.

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Investigation of temperature-dependent mechanical properties of CdS/PMMA nanocomposites

Journal of Composite Materials ◽

10.1177/0021998311401101 ◽

2011 ◽

Vol 45 (24) ◽

pp. 2507-2514 ◽

Cited By ~ 6

Author(s):

Sonalika Agrawal ◽

Dinesh Patidar ◽

N.S. Saxena

Keyword(s):

Mechanical Properties ◽

Weight Percent ◽

Cds Nanoparticles ◽

Temperature Dependent ◽

Stress Strain ◽

Strain Behavior ◽

Transmission Electron ◽

Low Weight ◽

Different Temperatures ◽

Solution Casting Method

Nanoparticles of chemically synthesized CdS with the different weight percents (0, 2, 4, 6, and 8 wt%) have been embedded into poly(methyl methacrylate) (PMMA) by solution casting method. The obtained CdS/PMMA nanocomposites are characterized through small-angle X-ray scattering and transmission electron microscope measurements. Temperature-dependent mechanical properties of CdS/PMMA nanocomposites have been studied at different temperatures (30, 50, 70, and 90°C) using stress–strain behavior through dynamic mechanical analyzer. Results indicate that CdS nanoparticles are uniformly distributed at low weight percent, and agglomeration of particles is observed at high weight percent and all the quantities obtained from stress–strain relations, i.e., Young’s modulus, tensile strength, and fracture energy increase up to 6 wt.% of CdS nanoparticles and then decrease for further increase of weight percent of CdS nanoparticles.

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