Tension impact test

Other impact tests widely used are the falling weight tests where a weight is allowed to fall onto a supported flat or domed surface and tensile impact tests in which a sample is subjected to a sudden shock in tension. Whilst the... 

Whenever changes in mechanical properties, such as performance in tension tests, fatigue tests, and impact tests, are to be used as a measure of... 

Methods employed to determine the impact resistance of plastics include pendulum methods (Izod, Charpy, tensile impact, falling dart, Gardner, Dynatup, etc.) and instrumented techniques. In the case of the Izod test, what is measured is the energy required to break a test specimen transversely struck (the test can be done either with the specimen notched or unnotched). The tensile impact test has a bar loaded in tension and the striking force tends to elongate the bar (Chapter 5, Impact Strength). 

In impact tests the order was the same except that Tritonal/D-2 95/5 and Picratol 52/48 were reversed Addnl work was conducted on the use of surfactants for reducing the interfacial tension between TNT and paraffin waxes. Refs 98 100 report results of tests using the n-octadecyl, n-hexa-decyl, n-dodecyl and n-hexyl esters of 2,4,6-trinitrobenzoic acid to permit stable homogeneous blends of paraffin waxes in molten TNT. It is reported that all these materials act as surfactants and that the interfacial activity increases as a linear function of the alkyl chain length of the ester. N-octadecyl 2,4,6-trinitrobenzoic acid also acts as a surfactant for the beeswax/TNT system. It was concluded, however, that the degree of reduction in the interfacial tension of... 

Note The MDMT at which impact testing would otherwise be required may be reduced in accordance with Figure UCS-66.1 when the stress in tension is less than the maximum allowable design stress. It may also be reduced 30° F (14.7 0) under UCS-66 if postweld heat treatment is performed when not otherwise required by Code. 

For fracture-critical tension members, Charpy impact test may be required,... 

The flaw spectrum approach may be capable also of correlating failure data obtained under conditions which appear to give different material behavior. For example, tensile, Izod, and dart drop impact tests all give different impact energies or toughness measures. In part, this may be explained by the simple idea that a different fraction of flaws is active in each test. Equal biaxial loading (as in dart drop) and uniaxial tension (as in tensile impact) give rise to different flaw activities thus it is to be expected that the number of crazes produced in each test will be different. 

PC/PE. In the case of PC/PE, plane strain alone does not produce significant changes in the yield stress and the deformation behavior. Its yield locus in the tension-tension quadrant is therefore either very nearly a quarter circle or similar to a Tresca locus. The exact shape of the locus can be determined only by much more elaborate biaxial tests. This material is not very notch sensitive compared with PC. The energy to break in a notched Izod impact test is 15 ft-lb/inch for Vs-inch thick bars and 11 ft-lb/inch for 4-inch bars whereas for PC the latter figure is about 2 ft-lb/inch. This reduction in notch sensitivity over pure PC appears to be related to the material s ability to void internally, probably relieving the plane strain. 

Fracture toughness tests for isotropic materials normally use edge-notched flexure beams and compact tension specimens. These methods are. as for the impact tests, only suitable for the injected or compression molded materials, which do not have a strongly laminated structure. Laminated composite materials have their primary failure path between the layers, and a new set of test geometries has been developed. 

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. 

Ishida et reported melt blending of PLA with four types of common rubbers, ethylene-propylene copolymer (EPM), ethylene-acrylic rubber (EAM), acrylonitrile-butadiene rubber (NBR) and isoprene rubber (IR), to toughen PLA. All blends showed separated phase morphology where the elastomer phase was homogeneously distributed in the form of small droplets in the continuous PLA phase. Izod impact testing showed that toughening was achieved only when PLA was blended with NBR, which showed the smallest rubber particle size in the blends. In addition, the interfacial tension between both phases, PLA and NBR, was the lowest. 

Tensile-impact test n. An impact test that uses a pendulum striker to break a dog-bone-shaped test specimen, described in ASTM D 1822 and 1822M. It differs from the Izod impact test in two important aspects (1) the specimen is not notched and (2) it is broken in simple tension rather than bending. For these reasons, its interpretation is more straightforward. 

Drop weight, standard and precracked Charpy impact, tensile test, and compact tension fracture toughness specimens are provided for unirradiated tests. Drop weight tests will be conducted in accordance with ASTM E-208. Charpy impact tests will be conducted in accordance with AGTM E-23. Tensile tests are conducted in accordance with ASTM E-8 and E-21. Correlation of drop weight and Charpy impact tests to establish will be made in accordance with NB2300 of the ASME Code, Section III. Charpy impact and tensile test specimens are provided for post-irradiation tests. 

This assembly (Figure 5.3-3) contains 3 base metal (transverse) tensile test specimens and 12 impact test specimens in the top section. The tension specimens are placed in a housing machined to fit the compartment. Split spacers are placed around the gage length of the specimens to minimize the temperature differential between the specimen gage length and the coolant. The impact specimens are arranged vertically in 1 x 3 arrays and are oriented with the notch toward the reactor core. Spacers are utilized between the test specimens and the compartment. The... 

Anaerobics are ideal for locking and sealing threaded parts and, with few exceptions (discussed separately in Section 2.3.2.9), are normally the only adhesives to consider. A variety of vibration and impact tests have shown that even medium-strength grades out-perform all conventional means of maintaining bolt tension (see Table 2.3). Frequently the test specimens fail due to metal fatigue with the nut still firmly attached to the bolt shank. 

In addition to plate thickness, decreasing temperature, increasing deformation rate, or environmental aging can transform ductile-type failure (Fig. 12A) to brittle-type failure. In the case of a ball or a hemispherical dart impact test, it is commonly assumed that the resultant stress state at the center of the plate is biaxial tension. This assumption is erroneous because the normal force on the plate is significant and could lead to over optimistic values on ductile-to-brittle transition conditions, whether expressed as a critical temperature or aging time. This behavior is caused by normal stress suppressing brittle failure (15,18,20). 

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