Pullout behavior

EN 13738 Geotextiles and GTX-Related Products Determination of Pullout Resistance in Soil 

DIN 60009 Geosynthetics Determination and Testing of the Interaction Coefficient to the Soil Using Pullout Test 

ASTM D6706 Standard Test Method for Measuring Geosynthetic Pullout Resistance in Soil 

Pullout tests are more sophisticated than direct shear tests because they are often larger in size. They are necessary to determine the friction properties of open structures such as geogrids but closed structures like GTXs do not necessarily have to be tested in pullout tests. Because a pullout test on a GTX can be seen as a double-sided direct shear test, a direct shear test will be much more appropriate to determine the friction characteristics of GTX than a pullout test. 

Nevertheless a puUout test can be used for GTX-W or for geocomposites like reinforced GTX-N but not for GTX-N. GTX-Ns will change their width too much owing to lateral contraction during the puUing of the specimen (Fig. 7.23). 

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Acceptable agreement between the experimental and the theoretical resrrlts reveals that the reported can predict the yam pullout behavior to an admissible extent. Besides, it proves that the equations of the force balance method are snitable enongh to be used for determining some important stractural and mechanical properties of the woven fabrics. Simplicity of the model principals and the few nnmbers of the experimentally required factors are the main achievements of this model. 

Badrossamay, M. R., Hosseini Ravandi, S. A., and Morshed, M. Fundamental Parameters Affecting Yarn Pullout Behavior. J. Tex. Inst, 92, 280-287 (2001). 

Furthermore, it seems that the applied mean dynamic friction coef Ciient (p ) for cotton fabrics is an overestimation of the real p. Here the two last parts of the pullout pro de has less conformity with the experimental results. Hence, the oscillation model is a more appropriate method to predict the pullout behavior of the fabrics composed of dament or even yams. 

Oscillation model, based on the force balance model, is an analytical method, capable of predicting the pullout behavior of the yams within the plain woven fabrics, fixed from two opposite sides. This method emphasizes on the vibratory behavior of the... 

Pan, N. Theoretical modeling and analysis of fiber pullout behavior from a bonded fibrous matrix The elastic-bond case. Journal of Textile Institute, 84, 472485 (1993). 

S. Singh, A. Shukla and R. Brown, Pullout behavior of polypropylene fibers from cementitious matrix , Cem. Concr. Res. 34, 2004,1919-1925. 

M.J. Shannag, R. Brincker and W. Hansen, Pullout behavior of steel fibers from... 

Tests on tin oxide fiber coatings in model composite systems indicated some crack deflection at the coating-fiber interface (Siadati et al., 1991 Venkatesh and Chawla, 1992). However, tensile tests of tin oxide coated alumina fiber-reinforced alumina matrix composites demonstrated a decrease in the extent of fiber pullout as the density of the matrix phase was increased. This led to increasingly brittle fracture behavior in these composites (Goettler, 1993). Tin oxide also has thermal stability problems at elevated temperatures (Norkitis and Hellmann, 1991). For example, in the presence of air at temperatures above 1300°C (2,372°F), tin oxide (solid) decomposes into SnO (gas) and Oj (gas). This decomposition occurs at even lower temperatures when the partial pressure of oxygen in the test environment is reduced. 

Pullout test is also a method, providing useful information about fabric tearing, its ability to absorb energy especially in ballistic applications, lllnishing efCbiency, bending, and shearing hysteresis of the fabric and Qially the frictional behavior of the fabric. 

After the [Tst junction rapture, the pulled yam slips in the weave. Therefore, the pullout force and consequently the fabric displacements decrease to some extent. But it increases later due to new adhesion formation. This happens in the second step, called the stick-shp motion, and recurs until the free end of the pulled yam leaves the [Ist crossover of the weave. Thereafter the stick-slip motion adopts a reductive trend, creating the third step. Figure 7 presents the yam pullout force displacement pro (He typically. It shows an oscillation behavior in the second and the third steps, due to the mentioned shps and adhesions. 

By three last decades, several models have been presented to simulate the behavior of woven fabrics in a yam pullout test. The advantage of this test is the simulation of internal frictional interactions. Concerning to the principals of the method [38] de-... 

To specify material properties, anisotropy, and non linear behavior of textile structures have to be considered. These assumptions make the assessments quite complex. However, previous studies showed that the simplifying linear elastic material could lead to reliable results in the modeling of yam pullout [1, 5, 10]. 

The stick-slip oscillatory behavior of the yam pullout test upon the vibration hypothesis. 

Pan, N. and Young Youn, M. Behavior of yarn pullout from woven fabrics theoretical and experimental. Textile Research Journal, 63, 629637 (1993). 

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