Drop towers

A five-meter drop tower was used to drop the coal lumps on different impact surfaces shown in Fig. 1. The different impact surfaces are steel plate, conveyor belt and coal stockpile. The details development of the drop tower was... 

Many applications of ceramic composites will expose the material to impact damage. Here again, the amount of work which has been done in this arena is limited, and needs to be increased. Impact tests can be performed using drop towers or Charpy impact testing apparatus. Such measurements have been done at room temperature30 and the apparatus can be adapted for use at elevated temperatures. 

A DROP TOWER METHOD FOR HIGH RATE FRACTURE TOUGHNESS TESTING... 

Dynamic properties, fracture toughness, fracture energy, dynamic modulus, dynamic testing, impact tests, drop tower, high strain rate. 

A Drop Tower Method for High Mte Fracture Toughness Testing of Polymers... 

A drop tower has been shown to be capable of performing high rate SENB tests and the associated tests such as elastic modulus and contact stiffness. Fracture toughness was assessed... 

A specially designed drop tower for evaluating powder samples was constructed and is shown in Fig. 

Fig. 9 Experimental arrangement for the drop tower (A) drop tower with oscilloscope, (B) sample tray formed by tube support and Plexiglas bottom, and (C) drop tower base showing the mounting of the PMT.

Dynamic Z,S—End-loaded split specimens were also tested in the drop tower, but were mounted horizontally in a custom clamping fixture as shown in Fig. 2. This fixture consists of a side grooved Palmgren vise (Chicago, IL) mounted to a custom pedestal. The pedestal is constructed of 50 x 50 mm steel box tubing welded to 6.4 mm steel plates and is clamped to the drop tower base using 100 mm C-clamps. In this case, a hemispherically-tipped steel tup is attached to the drop tower sled and travels downward, striking the end of the specimen as shown in the schematic in Fig. 2. 

Dynamic DCB tests were also conducted on both aluminum and composite adherends using the aforementioned drop tower. The results from the tests on aluminum are shown in Fig. 11, and those on composite are shown in Fig. 12. These figures show the apparent energy release rate, sampled at 2000 fiames/s and not necessarily the discrete initiation and arrest energy release rates. This apparent energy release rate is the applied energy release rate, not a critical value, over the duration of the test and possibly includes dynamic effects due to the test rate. 

Figure 10.16 IRT image showcasing the maximum thermal increase of the backside of an impacted PC/PET hehnet-grade material. An injection-molded plaque of 3.2 mm thickness was impacted with an instrumented drop tower at 3.0 m/s with a drop mass assembly of 5.0 kg that contained a rounded steel dart. No anvil was beneath the plaque therefore, deflection of the plaque was allowed to occur.

Figure 10.17 (a) Instrumented hnear drop tower (b-e) maximum compression and deformation of a helmet surrogate plaque-foam setup during an impact at 5.5 m/s ... 

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