FALLING WEIGHT

One can also do work by stirring, e.g. by driving a paddle wheel as in the Joule experiment above. If tire paddle is taken as part of the system, the energy input (as work) is detemiined by appropriate measurements on the electric motor, falling weights or whatever drives the paddle. 

ASTM D3029, Test Methodfor Impact Resistance of Rigid Plastic S heeting orParts by Means of a Tup (Falling Weight), Vol. 8.02, ASTM, Philadelphia, Pa., 1993. 

Impact Resistance. Tests for impact resistance of porcelain enamels include falling weight tests such as a free-falling ball or a pendulum... 

Impact tests are, however, used to try to compare the impact strength of different materials. Of these tests four require specific mention. These are the Izod test, the Charpy test, the falling weight tests and the tensile 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... 

Although the Izod and Charpy tests are widely used for plastics, other types of test are also popular. These include tensile impact tests and flexural plate (falling weight) tests. The latter is particularly useful in situations where the effects of flow anisotropy are being assessed. In addition, arbitrary end-product tests are widely used to provide reassurance that unforseen factors have not emerged to reduce the impact performance of the product. 

Where a valve is closed by the action of a falling weight, a short free fall should be allowed before the weight begins to close the valve. This assists in overcoming any tendency for the valve to stick in the open position. 

Joule s Researches (1848-1880).—(a) The heat produced in a coil of wire by induction currents set up on rotation between the poles of an electromagnet was communicated to water in which the coil was placed, and was compared with the work done by falling weights in rotating the coil (1848). 

We test the impact resistance of polymer plaques using the configuration shown in Fig. 8.8. We subject circular injection molded plaques to the shock of a falling weight with a hemispherical impacter. This test is also known as the Dart Drop Test . Samples can fail in a brittle or a ductile manner. Brittle samples often shatter. Ductile samples can split or a small disk may be punched out of their center. This test provides results that are analogous to those obtained from un-notched impact beam testing. 

Describe how we perform toughness testing on polymers with both the impact beam and the falling weight methods. Explain the different manners by which an amorphous polymer will fail above and below its glass transition temperature. 

Type Fall (%) Find (%) Fall weight (kg) Find weight (kg)... 

Genera/- Alopecia fever hyperthermia hyperpyrexia local edema nasal stuffiness increased perspiration proneness to falling weight gain or loss. 

IMPACT SENSITIVITY OR SHOCK SENSITIVITY TESTS (Drop Weight or Falling Weight Tests). A list of various tests with refs is given in Vol 1, p XVII. Brief descriptions of US Bureau of Mines (BM) Apparatus and of Picatinny Arsenal (PA) Apparatus are also given on p XVII. British test called Figure of Insensitiveness (FI) is described on p XII (See also Refs 36, 38d, 41, 42, 53, 55b,... 

Marshall 2(1917) Falling Weight Test (Lenze) (p 423) Friction Sensitivity Test (423) Sensitiveness to Detonation (429) Sensitiveness to Heat (434) Ignition Temperature (434) Heat of Explosion (440) Trauzl Test (469) Strength by Ballistic Pendulum (473) Velocity of Detonation by Dautriche Method (479) Brisance Meter of Hess (495)... 

Lead Block and Copper Cylinder Compression Tests (113-15) Ballistic Pendulum Test (115-16) Fragmentation Test (Geschoss-Splitter Probe (118) Impact Test by Falling Weight (118-20) Deflagration Point (Verpuf-fungstemperatur) (120) Friction Test (120-21) Rifle Bullet Test (Beschussprobe) (121)... 

The Impact Test, also called Falling Weight Test was devised by W. Will, SS 1, 209(1906) and by H. Kast, SS 4, 263 (1909) and the history of test was reviewed by H. Koenen et al in Explosivstoffe 8, 178(1958). The test differs essentially from the gap test because its pressures (several hundred, or up to several thousand atmospheres) are much lower and its time scale (hundreds of microseconds, depending on the length of the hammer) much longer. In the test conducted at NOL, a 35-mg sample of expl or propint was placed on a... 

Shock involves motion - that of a falling weight which impacts other matter, that of two railroad trains in collision or that of the highly compressed gases in a detonation which occupy the reaction zone back of the shock zone, which impacts the next monomolecular layer of undecomposed explosive. The velocity of such motion therefore is an important factor in the shock value of the phenomenon... 

A 40mg sample is placed on a brass cap which is inverted over the anvil. The falling weight is normally 5kg. If the volume of gas evolved by a 0.03mg sample is more than 1ml, then the test is considered a go. The Bruceton method is used and results are reported as Figure of Insensitiveness or FI which is ob-... 

Impact Sensitivity Data Obtained with the Rotter Apparatus at ARDE (5kg falling weight 30mg samples)... 

---