Impact Resistance Tests Research Articles

Failure of Bags and Sheets Used in Asbestos Abatements

Plastic films are widely used in asbestos stripping operations as sheets to contain fibers within the operation and to bag and wrap asbestos waste. Mechanical failure of these films is not infrequent. The mechanical properties of single samples of seven Australian films were investigated and it was found that no film passed all tests to British Standard 4932: 1973. Thicker films with good tensile strength, elongation, tear resistance, and burst strength failed impact resistance and tensile-impact strength tests, while thin films had good impact properties. The results of these tests are discussed in terms of failure in the field, but the relationship between passing or failing a test and failure in the field is not known.

Instrumented Impactor for Testing Wood-Base Floor Panels

Abstract The current ASTM method for evaluating impact resistance (ASTM E 661), which uses a leather bag filled with 14 kg (30 lb) of lead shot, is adequate for comparative rating of panels. Our objective was to obtain a more precise measure of failure initiation. An instrumented steel impactor was developed to evaluate the impact resistance of single-layer wood-base floor panels. Panel materials evaluated were plywood, waferboard (two manufacturers), and oriented strandboard. All were nominally 19 mm (¾ in.) thick with tongue-and-groove edges and were approved for single-layer flooring. Impact resistance tests were conducted on the panels using a 14-kg (30-lb) lead-shot bag, a 14-kg (30-lb) steel impactor, and a 27-kg (60-lb) steel impactor. Floor panel damage was measured by the amount of energy absorbed by the panel, time to maximum deflection, and residual panel deflection (permanent set). The 14-kg (30-lb) impactor proved to be more precise for identifying damage initiation because the 27-kg (60-lb) impactor caused complete failure of some waferboard and oriented strandboard after only two or three drops. For all panel types, the 14-kg steel impactor caused 30 to 40% greater deflection than the 14-kg lead-shot bag for any given drop height.

Effect of overheating on fatigue strength and other mechanical properties of carburized and uncarburized VAR 582 steel

Rotating cantilever fatigue tests were made on two vacuum-arc remelted casts of S82 (4%Ni) steel which had been preheated andforged to give a 25% reduction at 1060°, 1260°, 1300°, or 1340°C and then fully heat treated. Statistical analysis was applied to the results. Impact, tensile, fracture toughness, and stress corrosion resistance tests were carried out,. measurements of fatigue crack growth rate and a study offatigue crack initiation were also made. The tests showed that overheating, including fairly severe overheating, had no significant detrimental effect on fatigue properties, tensile strength, and fracture toughness but that it caused reductions in tensile ductility, impact toughness, and stress corrosion resistance.

Impact resistance tests of contemporary safety glasses, goggles, and face shields

The person delegated to purchase safety glasses, goggles, and face shields for laboratory workers should know what specifications are important, and what may be critical.

Phenomenology of impact resistance and impact testing

The impact resistance of plastics can be described in terms of three contributions; these are the elastic, plastic, and crack propagation phases. By using a recording pendulum impact device it is possible to analyze any material as to the relative importance of the above phenomena. It was found that most plastics which exhibit good impact resistance have large plastic elongations or good resistance to crack propagation or both. A simple analysis of the cantilever beam impact shows that reasonable values of modulus and of maximum fiber stress can be obtained if care is taken to account for shear and compressive contributions to the overall response. It was also noted that plastic samples under impact conditions tend to bounce against the striker head.

Wetting Properties of Some Enamel Glasses and Relation to Impact Resistance

The wetting properties of some enamel glasses on commercially pure enameling iron were determined and compared with correlated impact resistance test results. The rate of change of wetting characteristics with temperature seemed to influence the impact resistance of the enameled metal.