Flexural creep behavior

Figure 3.82 Flexural creep behavior of 25% by weight glass-filled ETFE as a function of stress, time, and temperature...

F. Abb6, Flexural creep behavior of a 2D SiC/SiC composite. Ph. D. thesis. University of Caen, 1990. 

Flexural Creep Behavior of Mega-Coupled GFRP... 

Banik K, Abraham T N and Karger-Kocsis J (2007) Flexural creep behavior of unidirectional and cross-ply all-poly(propylene) (PURE ) composites, Macromol Mater Eng 292 1280-1288. 

Izer A and Bdrdny T (2010) Effects of consolidation on the flexural creep behavior of all-polypropylene composite. Express Polym Lett 4 210-216. 

Figure 20.3 is from Express Polymer Letters, Vol. 4, 2010, Authors Izer A and Barany T, Title Effects of consolidation on the flexural creep behavior of all-polypropylene composite, pp. 210-216, Copyright (2010), with permission from Express Polymer Letters. 

Cyras, V.P., Martucci, J.F., lannace, S., and Vazquez, A. (2002) Influence of the flber content and the processing conditions on the flexural creep behavior of sisal-PCL-starch composites. 

Chevali, V.S., Dean, D.R., Janowski, G.M. Effect of environmental weathering on flexural creep behavior of long fiber-reinforced thermoplastic composites. Polym. Degrad. Stab. 95, 2628-2640 (2010)... 

Flexural creep behavior of nylon 6/6 based long fiber thermoplastics (LFT) was determined nsing transient and dynamic testing methods. While the eflect of increasing fiber volume fi action reduced creep, there was only a negligible effect of flow orientation effect. The creep data generated by dynamic mechaitical analysis (DMA) tests was consistent with the transient tests. 

Although the creep behavior of a material could be measured in any mode, such experiments are most often run in tension or flexure. In the first, a test specimen is subjected to a constant tensile load and its elongation is measured as a function of time. After a sufficiently long period of time, the specimen will fracture that is a phenomenon called tensile creep failure. In general, the higher the applied tensile stress, the shorter the time and the greater the total strain to specimen failure. Furthermore, as the stress level decreases, the fracture mode changes from ductile to brittle. With flexural, a test specimen... 

Similarly, Figure 6 summarizes the creep behavior of glass-and mineral-filled polyphenylene sulfide under three sets of conditions 24°C/5,000 psi flexural load, 66°C/5,000 psi, and 1210C/3,000 psi. Table III compares the per cent loss In apparent creep modulus at 1,000 hours and at 10,000 hours for each of these conditions using the apparent creep modulus at one hour as a basis. These data Indicate that the creep resistance of the glass- and mineral-filled polymer Is similar to that of the 40% glass-filled resin. 

Flat bulk sample, bars Loading/unloading cycles Flexural probe (three-point bend) Significant load Linear displacement Time Temperature crosslink density Creep behavior Softening temperature, heat... 

The reinforcement effect of sisal fiber content on the flexural creep performance and flexural modulus of cellulose derivatives/ starch composites was studied by A1 Verez et al. [15]. Fiber content and temperature effects were also considered, taking into account various methods and equations. At short times, a creep power law was employed. A master curve with the Arrhenius model was used to determine the creep resistance at longer times and different temperatures. Good fitting of the experimental results with the four-parameter model was reported, leading to a relationship between the observed creep behavior and the composite morphology. The addition of sisal fibers to the polymeric matrix promoted a significant improvement of the composite creep resistance. 

Flexural creep compliance, 10 Flexural load, 44 Flow behavior, 3... 

Loads on a fabricated product can produce different t3q>es of stresses within the material. There are basically static loads (tensile, modulus, flexural, compression, shear, etc.) and dynamic loads (creep, fatigue torsion, rapid loading, etc.). The magnitude of these stresses depends on many factors such as applied forces/loads, angle of loads, rate and point of application of each load, geometry of the structure, manner in which the structure is supported, and time at temperature. The behavior of the material in response to these induced stresses determines the performance of the structure. 

Experimental creep data for ceramics have been obtained using mainly flexural or uniaxial compression loading modes. Both approaches can present some important difficulties in the interpretation of the data. For example, in uniaxial compression it is very difficult to perform a test without the presence of friction between the sample and the loading rams. This effect causes specimens to barrel and leads to the presence of a non-uniform stress field. As mentioned in Section 4.3, the bend test is statically indeterminate. Thus, the actual stress distribution depends on the (unknown) deformation behavior of the material. Some experimental approaches have been suggested for dealing with this problem. Unfortunately, the situation can become even more intractable if asymmetric creep occurs. This effect will lead to a shift in the neutral axis during deformation. It is now recommended that creep data be obtained in uniaxial tension and more workers are taking this approach. 

We have already referred to various kinds of data on mechanical behavior of polymers. We are now going to consider methods of acquisition of such information. The most fi equently used are the so-called quasistatic methods which involve relatively slow loading. Tension, compression, and flexure belong here. The quasistatic methods have to be distinguished from so-called transient tests which include stress relaxation and creep. There are also impact tests and dynamic mechanical procedures which will be defined later. 

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