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Seismic transmission measurements in salt
Published in B. Côme, P. Johnston, A. Müller, Design and Instrumentation of In Situ Experiments in Underground Laboratories for Radioactive Waste Disposal, 2022
The easiest way of excitation is a hammer: blow on a metal anvil which is in good contact to the rock. The electric contact between hammer and anvil can be used to trigger the signal recording (time reference). At older walls or floors the coupling of the signal to the rock may be very poor by this method, because wall-parallel cracks may have formed some 10 cm behind the wall (or floor). In such cases we use drill holes of at least 50 cm depth with a metal rod in it which replaces the anvil. The hammer mostly used has a weight of 0.5 kg.
Types of piles and their installation
Published in Rodrigo Salgado, The Engineering of Foundations, Slopes and Retaining Structures, 2022
Pile driving hammers are devices used to deliver blows to the head of a pile to drive it into the ground. A variety of pile driving hammers are available. They vary in the rate at which blows are delivered, the maximum amount of energy delivered in any one single blow, and the duration of the blow. To a large extent, these performance parameters reflect the mechanism of operation of the hammer. There are basically four types of hammers: gravity or drop hammers, single-acting hammers, double-acting hammers, and differential hammers. Table 12.4 summarizes the main features of each type of pile driving hammer.
Fitting using hand skills
Published in David Salmon, Penny Powdrill, Mechanical Engineering Level 2 NVQ, 2012
Most hammers are available in a range of weights, typically between 225 gm ((12lb)) and 900 gm (2 lb). Bigger hammers than this are called sledge hammers and are used for very heavy work. Hammer handles are made from good quality ash or hickory wood.
Reverse reconstruction of motorcycle-car accident based on response surface model and NSGA-II algorithm
Published in International Journal of Crashworthiness, 2022
Qian Wang, Yunfeng Lou, Tong Li, Xianlong Jin, Lingshuang Kong, Xinyi Hou
The head impact simulation is based on the Yogananda experiment that the impact hammer strikes the head without any anti-corrosion treatment. In the test, the bottom of the head is fixed on the test bench as shown in Figure 4. The hammer is a rigid ball with a diameter of 0.1 m and a weight of 1.2 kg. The initial conditions of the simulation are also consistent with those in the experimental test.