Dependence of mechanical properties

Softening as a result of micro-Brownian motion occurs in amorphous and crystalline polymers, even if they are crosslinked. However, there are characteristic differences in the temperature-dependence of mechanical properties like hardness, elastic modulus, or mechanic strength when different classes of polymers change into the molten state. In amorphous, non-crosslinked polymers, raise of temperature to values above results in a decrease of viscosity until the material starts to flow. Parallel to this softening the elastic modulus and the strength decrease (see Fig. 1.9). 

As was the case for metals, poly crystalline ceramics show a dependence of mechanical properties on grain size, as given earlier by the Hall-Petch relation in Eq. (5.22), which in this case applies to fracture strength, ay ... 

The increment in mechanical properties (tensile strength, 300% modulus, and Young s modulus) as a function of SAF is plotted in Fig. 39. In general, the higher level of SAF, which in turn indicates better exfoliation, results in high level of property enhancement. However, the level of increment with the increase in SAF is different in all three cases and follows a typical exponential growth pattern. The apparent nonlinear curve fitting of the experimental values presented in Fig. 39 is a measure of the dependence of mechanical properties on the proposed SAF function. 

Silver, F. H., Christiansen, D. L., Snowhill, P. B., and Chen, Y. (2001). Transition from viscous to elastic-based dependency of mechanical properties of self-assembled type I collagen fibers./. Appl. Polymer Sci. 79, 134-142. 

On the other hand knowledge of these functions and of the spectra of relaxation (or retardation) times derived from them, is very helpful for obtaining insight into the molecular mechanisms by which they are originated. Analysis of the time dependency of mechanical properties thus provides a powerful tool to investigate the relations between structure and properties. 

Time Dependence of Mechanical Properties and Domain Formation of Linear and Crosslinked Segmented Polyurethanes... 

Fig. 9. Dependence of mechanical properties of highly-loaded composites (series 7, Table 2) on their free volume. Pp, — breaking stress, MPa x 10 2.

The typical dependence of mechanical properties of Ti-Si binary alloys in as-cast and as-deformed states is shown in Fig. 3. It is seen that in as-cast state room temperature plasticity decreases with increase of silicon content, reducing practically to zero at silicon content of 2-3 wt. % then it raises a little at eutectic formation. Unfortunately, our attempts to increase room temperature plasticity in as-cast condition more or less substantially via employing various kinds of heat treatment procedures were not successful. At the same time, using thermo-mechanical treatment (forging at temperature 1050 °C), it was possible to increase plasticity of deformed alloys essentially. 

It was noted above, that the as-cast eutectic alloys of binary Ti-Si system have no appreciable plasticity at room temperature. Alloying with aluminum, zirconium and use of various modifiers has also not allowed appreciable RT plasticity to be obtained. Data on temperature dependence of mechanical properties of deformed alloys of system Ti-3A1 6Zr-(2-6) Si show that, in contrast to as-cast alloys, deformed state with about 2 % Si demonstrate high plasticity ( 4%) reducing to 1.8 % in alloy with 6-wt.% Si. At the same time high-temperature strength of these alloys are practically the same, at 540-560 MPa level (600 °C). In such a way there is no reason to increase silicon content higher 2-wt.% in deformed state. 

The dependence of mechanical properties on irradiation dose for elastic modulus, percent extension, and work are summarized in Figures 4, 5, and 6, respectively. 

Dependence of mechanical properties on the amino acid content in the silk of Nephila clavipes has been investigated using solid state NMR and amino acid analysis. ... 

Figure 2.6 Dependencies of mechanical properties of angle interlock reinforced composite on parameters of the reinforcement (normalised values) (a) Young s modulus in the warp direction, Ff = 58% (b) Young s modulus in the weft direction, Ff = 58% (c) shear modulus, Ff=58% (d) Young s moduli versus fibre volume fraction, PSl and PS2 refer to two values of the weft spacing.

Fig. 10. Temperature dependences of mechanical properties of superconducting Cu-plated Ti-40Nb and Ti-50Nb cables.

M. Oshima, R. Sato, F. Hayashi and W. Koyanagi Thermal properties and temperature dependency of mechanical properties of resin concretes for structural use. in Proceedings of the 10th International Congress on Polymers in Concrete (CD-ROM), Department of Civil Engineering, The University of Texas at Austin, Austin, Texas (2001). 

This model predicts that the elastic properties of single- and multi-walled nanotubes should be insensitive to the radius, heHdty, and the number of walls [113]. Numerous other studies based on different models predict high strength values for single- as well as multi-walled CNTs [114,115]. However, the dependence of mechanical properties on the tube diameter and helicity predicted using different models contradict each other [112,113]. 

Causa F, Manto L, Borzacchiello A, De Santis R, Netti P, Ambrosio L, Nicolais L (2002) Spatial and structural dependence of mechanical properties of porcine intervertebral disc. J Mater Sci Mater Med 13 1277-1280... 

Only two sources of data for the temperature dependence of mechanical properties of samarium were found. The data are shown in figs. 8.28 and 8.29. 

The grain-size dependence of mechanical properties is also observed in ceramics. Thus, one can state that the H-P relation is a general observation of most materials, metals and ceramics alike. Deviations from the linear H-P plots, known as the inverse H-P trend, observed in metals having small dimensions, will be discussed later on in the chapter dedicated to that topic. 

Pekala RW, Alviso CT, LeMay JD (1990) Organic aerogels microstructural dependence of mechanical properties in compression, J Non-Cryst Solids 125 67-75... 

Fig. 3.1-67 Dependence of mechanical properties of naturally aged G-AlCu4TiMg casting alloy on the maximum solution treatment temperature (1) Step annealing (2) Single step annealing...

The use of nanomechanical measurements is, of course, an alternative approach to that described in this paper for the chemical imaging of polymers. We beheve, however, that it is likely to be more prone to ambiguity, due to the dependence of mechanical properties on processing conditions. 

Typical values of Young s modulus for various forms of SiC illustrate the dependence of mechanical properties on microstructure and production method ... 

In contrast to the strong dependence of mechanical properties on the CB localization shown in Figure 6.16(a), the mechanical properties of silica filled SBR/BR blends seem not to be influenced by the given silica loading pre-mixed in the SBR phase as seen in Figure 6.16(b). 

The examples show the great dependence of mechanical properties on type, shape, and morphology of the materials, stress level, and type of loading and surrounding conditions. Detailed knowledge of material morphology is necessary to understand structure-property correlations and to find possibilities for improvement of the... 

Studied effect of molecular composition leading to changes in the mesophase state on flexural modulus. Revealed thickness and test-direction dependence of mechanical properties. 

Boldizar 22 HBA/HNA Studied effect of injection rate, gate geometry, part thickness, and use of an exit cavity. Emphasized the need to direct attention to gate design, and confirmed thickness dependence of mechanical properties. 

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