View source for Impact Loading Pendulum Impact Tester

{{Language_sel|LANG=ger|ARTIKEL=Schlagbeanspruchung Pendelschlagwerk}}
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<span style="font-size:1.2em;font-weight:bold;">Impact loading, plastics, pendulum impact tester</span>
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==General information==

[[Plastics]] or [[Fibre-reinforced Plastics|composite plastics]] are increasingly being used in machines, vehicles and aircraft for lightweight construction purposes. In the event of crash loads and explosions of containers or pipelines in the chemical industry, [[Impact Loading Plastics|impact loads]] can occur which superimpose themselves on the existing static/dynamic load collective. These impact loading conditions usually cause locally greatly increased [[Deformation Rate|deformation rates]] and are further intensified by the presence of [[Stress|stress]] peaks at sharp [[Notch|notches]], internal cavities ([[Gas Bubbles|gas bubbles]], [[Shrink Voids|vacuoles]], [[Micropores|micropores]]) or edges, [[Multiaxial Stress State|multiaxial stress states]] and low temperatures [1].

Since the molecular [[Relaxation Plastics|relaxation]] and [[Creep Plastics|creep mechanisms]] in plastics require sufficient reaction time, high impact speeds and/or very low temperatures significantly influence the [[Deformation Mechanisms|damage]], [[Strength|strength]], [[Deformation|deformation]] and [[Component Failure|failure behaviour]], as the time required for the material to react to the impact loading is no longer available. The local [[Strain Rate Basics|strain rate]] d''ε''/d''t'' or the characteristic exposure time of the impact load is decisive for the effect of the impact load on the plastic.

==Conventional characterisation of toughness==

In addition to knowledge of [[Strength|strength]], [[Deformation|deformation behaviour]] under static and dynamic [[Stress|loaded conditions]], and [[Stiffness|stiffness behaviour]], determining the [[Toughness|toughness]] of the materials used is also very important. In industrial research and development, pendulum impact testers ('''Fig. 1''') are usually used for this purpose, as they allow conventional characterisation of toughness behaviour, including as a function of [[Toughness Temperature Dependence|test temperature]].

[[File:Impact Loading Pendulum Impact Tester - Fig-1.jpg|350px]]
{| 
|- valign="top"
|width="50px"|'''Fig. 1''': 
|width="600px"|A schematic diagram of a conventional pendulum impact tester
|}

With such pendulum impact testers, the energy consumed by the [[Specimen|test specimen]] during the impact is determined based on the potential energy of the pendulum hammer in the starting position ''α'' or ''h''<sub>1</sub>, which is expressed in the lower height ''h''<sub>2</sub> or angle ''β''. If the quotient of the energy consumed and the cross-sectional area is calculated, the impact or [[Notched Impact Test|notch impact strength]] of the [[Material & Werkstoff|material]] under investigation is obtained, depending on the type of test specimen used.

==Test arrangements==

In testing practice, in addition to the [[Tensile Impact Test|tensile impact test]] for impact bending loads, the test arrangements according to [[Impact Test#Charpy impact test|CHARPY]], [[Impact Test#Izod impact test|IZOD]] or [[Impact Test#Dynstat impact test|Dynstat]] are used, whereby the test methods do not produce comparable results due to different [[Test Speed|test speeds]] (2.9 to 3.9 m/s).

In Germany and other European countries, the test arrangement according to [[Charpy, Georges|CHARPY]] in accordance with ISO 179-1 [2] is preferred, whereby unnotched and [[Notching|notched test specimens]] can be tested in an edgewise or flatwise arrangement ('''Fig. 2''').

[[File:Impact Loading Pendulum Impact Tester - Fig-2.jpg|425px]]
{| 
|- valign="top"
|width="50px"|'''Fig. 2''': 
|width="600px"|Test arrangement according to [[Charpy, Georges|CHARPY]] (a) edgewise or e and (b) flatwise or f
|}

However, the results of the edgewise or flatwise test are not comparable for the unreinforced or [[Short-fibre Reinforced Plastics|short-fibre reinforced]] and [[Particle-filled Thermoplastics|filled plastics]] tested. In the case of laminates or highly oriented test specimens made of plates, the test direction is also varied depending on the direction of removal. If the pendulum impact tester is equipped with a temperature control device, [[Toughness Temperature Dependence|temperature-dependent toughness values]] can also be determined to characterise [[Brittle-Tough Transition|brittle-tough transitions]]. These transition areas are of particular importance when using these [[Plastics|plastics]], as they have a significant influence on the dominant failure mechanism (deformationless [[Fracture Types|brittle fracture]] or ductile [[Fracture|fracture]]).

==Device systems==

Depending on their age and level of equipment, these testing systems can be equipped with analogue measurement recording (trailing pointer with manual reading), digital measurement processing or incremental measurement technology (angle encoder) ('''Fig. 3''').

[[File:Schlagbeanspruchung_Pendelschlagwerk-3.JPG|600px]]
{| 
|- valign="top"
|width="50px"|'''Fig. 3''': 
|width="600px"|Analogue pendulum impact testing device (a), analogue pendulum with digital measurement evaluation (b) and incremental pendulum impact testing device (c) from [https://www.zwick.de Fa. ZwickRoell GmbH & Co. KG, Ulm] 
|}

==See also==

* [[Impact Loading Plastics|Impact loading plastics]]
* [[Impact Test|Impact test]]
* [[Instrumented Charpy Impact Test|Instrumented Charpy impact test]]
* [[MPK-Procedure MPK-ICIT]]
* [[Instrumented Tensile Impact Test (ITIT)|Instrumented tensile impact test (ITIT)]]

==References==

{|
|-valign="top"
|[1]
|[[Grellmann, Wolfgang|Grellmann, W.]]: Impact Loading. In: [https://www.researchgate.net/profile/Wolfgang-Grellmann Grellmann, W.], [[Seidler, Sabine|Seidler, S.]] (Eds.): Polymer Testing. Carl Hanser, Munich (2022) 3rd Edition, pp. 143–156 (ISBN 978-1-56990-806-8; E-Book: ISBN 978-1-56990-807-5; see [[AMK-Library]] under A 22) 
|-valign="top"
|[2]
|ISO 179-1 (2026-03): Plastics – Determination of Charpy Impact Properties – Part 1: Non-instrumented Impact Test
|}

[[Category:Bend Test]]
[[Category:Impact Tests]]