Notch tensile test

Non toughened semi-crystalline PET is a very brittle polymer whatever the loading conditions are i.e., un-notched and notched tensile tests, dart test (impact of a hemispherical striker against a clamped plaque) and izod test (Fig. 1. to Fig.4.). Amorphous PET exhibits a more ductile behaviour except when notched. In such a case even amorphous PET is a brittle material at room temperature (Fig. 3. and 5.). 

Standard Test Method for Notch Tensile Test to Measure the Resistance to Slow Crack Growth of Polyethylene Pipes arui Resins, ASTM F1473-01. 

Figure 10. TEM image of stained PA-polybutadiene (15 vol%) after undergoing tough fracture in a notched tensile test at high speed (1 m/s). The section shown is next to the fracture surface (18).

The notched tensile test specimens used in this investigation are shown in Fig. 1. For most tests, the notched specimens were used with a notch concentration factor of Kt — 6.3, as determined after Neuber [ ]. In one series of tests a of 15.0 was used. Each notched specimen was checked with a Jones Lamson optical comparator at 50 x. Only those specimens with notched dimensions within the specified tolerances were tested. 

PENT Pennsylvania edge-notch tensile test... 

Material Notched Tensile- Test Conditions Refn... 

ASTM F 1473 Standard test method for notch tensile test to measure the resistance to slow crack... 

TENSILE AND NOTCH-TENSILE TESTS. Figure 2 illustrates the general design of the tensile specimen. The following tensile specimen diameters were... 

Tensile and notch-tensile tests of AISI 304 were conducted at the four test temperatures listed above. In addition, two other variables, strain rate and thermal cycling, were introduced. The strain rates employed were those resulting from crosshead speeds of 0.005, 0.02 and 0.2 in. per min. at each test temperature. To determine the effect of thermal cycling on mechanical properties of AISI 304 in the absence of spontaneous martensitic transformation, one half of all the specimens were subjected to temperature cycling between 300° and 76°K (holding at 76°K) for a period of one year [2]. 

Question by L. E. Scott, CEL-NBS In the correlation between notched tensile tests and actual applications, what ratio of notched to unnotched do you use as a criterion of brittleness ... 

Fig. 12.12 Summary results of notch tensile tests on mechanically-stress-relieved specimens (modified from [10])...

In the investigation reported herein, the mechanical properties of type 301 stainless steel were studied at 70, -320 and -423 F in samples of steel that had been cold-worked 42, 62, and 78. Toughness was studied by means of notched tensile tests at the same temperatures, and a notch-to-unnotch tensile ratio was calculated. The latter was taken as a criterion of resistance to brittle fracture. In addition, the tensile properties of heliarc butt-welded joints of the same materials were determined. The welded joint data were included because low-temperature properties of welded joints are of practical importance in pressurized cryogenic propellant tanks. 

Development and Application of the Notched Tensile Test to UHMWPE... 

This chapter describes our development of the notched tensile test and findings for three studies [1-3] in which we evaluated two to five formulations of conventional and highly crosslinked UHMWPEs (Table 31.1). 

The novel video-based method used for the evaluation of axial stress-strain behavior of notched cylindrical specimens is a valuable tool. Experimentally, this method is simple to implement and has the advantage of providing strain behavior up to failure using a noncontacting extensom-etry approach. The notched tensile test is also an attractive experimental method with which to check the validity of the development of constitutive models of UHMWPE (see Chapter 35). The methodology has the advantage of creating a multiaxial stress state without contact, and the specimen can be modeled as axisymmetric in finite element analyses. 

ASTM F1473 describes test specimens from pipe and from the resiit This presentation will be focused on PENT testing of the resin from compression molded plaques. PENT is a sin e edge notch tensile test A representative specimen is shown in Figure 3. Other dimensions are given in the specification. In the specification a standard value of K = 0.468 MPa m has been established. This value was chosen to insure that all PE would fail by the mechanism of SCG at 80°C. If K is too high, the failure could occur by a complex combination of shear deformation and fiacture which is not the long time mode of failure that occurs under field conditions. The thickness of the compression... 

---