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Resilience

Lüpke Pendulum - R1

Features
		Direct measurement of rebound resilience as percentage
		Fine wire suspension reduces air drag
		Magnetic catch ensures no energy is imparted to pendulum at start
		Rebound data computer easily fitted
		Simple construction
		Solid wall or similar structure required for pendulum mounting

To find out more about this product contact Wallace

Introduction

Resilience is the ability of a rubber vulcanisate to return the energy used to deform it, during its recovery from the deformation. A percentage of the energy used in the deformation is dissipated as heat, and thus is not available as elastic energy during the recovery.

The rebound resilience, which is the property measured by the Lüpke pendulum, is the percentage ratio of the energy returned during an impact to the energy input.

Resilience measurements are subject to certain main errors: drag in air , friction, vibration in the apparatus and whip due to elasticity in solid pendulums. The Lüpke Pendulum avoids these errors for the following reasons: Air resistance is negligible due to the smallness of the moving parts; there are no bearings to cause friction, vibration is impossible and whip in the fine wire suspension is of no consequence. No correction factors are required with the Lüpke Pendulum.

The apparatus consists of a pendulum in the form of a horizontal rod of 350 g. mass which is suspended on four fine wires which is released from a given height to strikea test piece. The rebound of the pendulum is the measurement of resilience.

The pendulum rebounds from the test piece and the extent of rebound is indicated by a pointer which travels over a scale positioned concentrically with the path of the rod. The scale is divided into one hundred divisions, representing percentage rebound.

A magnetic catch ensures that no energy is imparted to the pendulum at the instant of release. The apparatus can be secured to a solid perpendicular structure such as a brickwall preventing movement of the test piece holder due to the impact of the pendulum.

Optional Extras


Test Piece Mould - Ref. R.1/1	A six-cavity (three plate) Test Piece Mould for preparing test pieces
Low Temperature Test Piece Holder - Ref. R.1/2	Assembly, complete with temperature controller for sub-zero temperatures, using liquid nitrogen as a refrigerant.
High Temperature Test Piece Holder - Ref. R.1/3	Supplied with digital temperature controller. The maximum temperature is 100°C.

Rebound Resilience Data Computer - Ref. R.3

Automatically computers resilience and displays the result as a percentage on a digital readout. It reduces testing time, avoids the neccessity for calculations and enables unskilled operators to obtain accurate and consistent results.

Specifications

See the table below for a run-down of this product's specifications.

Pendulum mass:	350g
Wire specification:	10 Amp fine wire 0.006mm dia
Vertical height of pendulum:	2000 ± 2mm
Low temperature test piece holder:	-70°C.
High temperature test piece holder:	100°C.
Temperature tolerance:	±1°C