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Vibrations and impact forces of modified handle pneumatic hammer

Majewski Tadeusz, Meraz Melo Marco, Tracz Jan, Ładyżyńska-Kozdraś Edyta, Estrada Quirino

Advances in Science and Technology. Research Journal

2025

Vol. 19, no. 3

341--349

The paper presents a dynamic model of a small electro-pneumatic percussive tool whose handle is elastically connected to the casing. The pneumatic force is defined as a function of the position of the piston and the striker. The Hertz model has been applied to the impact forces and given the conditions under which they exist. The differential equations define the movement of each part of the hammer. Their simulations show how the hammer parts vibrate, when the impacts occur, and how large the impact forces can be. The acceleration of the handle is determined and compared with the acceleration when the handle is part of the casing. The article proves that the hammer with a floating handle is better for the operator's protection.

Methodology of Testing for Aluminium Honeycomb Impact Attenuator in Quasi-Static Conditions and Influence of Supporting Structures

Tracz Jan, Rządkowski Witold, Majewski Tadeusz, Meraz Melo Marco Antonio, Cisowski Adam, Zawiśliński Krzysztof, Urbański Dawid, Figurski Aleksy, Ładyżyńska-Kozdraś Edyta

Advances in Science and Technology. Research Journal

2024

Vol. 18, no. 8

46--55

This paper examines the influence of two different supports, i.e., composite and steel, on the results obtained during a quasi-static crush test of an aluminum alloy honeycomb impact attenuator. It’s part of a vehicle that competes in the Formula Student series and requires safety tests to be eligible to participate in events. The attenuator is tested in two configurations – first with a rigid steel support base and second – with a composite support base, which represents a realistic replica of the first 50mm of carbon fiber monocoque used in a vehicle. The composite base is less stiff and must be tested with the impact attenuator as it is a possible safety weak point. The testing machine was an Instron 8516 set to a 60mm/min feed speed with a sampling rate of 1kHz. The results showed that the values of energy absorbed were higher (7983.9J to 8732.1J) for the case with a composite base support, whereas the average forces were similar (about 50kN). This suggests that a more realistic scenario allows for a higher safety margin rather than a decrease in it. The recommendation is to address the possible energy cumulation as elastic deformation (spring-back effect), which might be unwanted. Further studies could include dynamic testing and other attenuator designs.