Creep test bench

THE SOLUTION PROVIDED BY LF TECHNOLOGIES

Our client, the technical centre for mechanical industries, aims to provide mechanical companies with the means and skills to increase their competitiveness, participate in standardisation and act as a link between scientific research and industry.

Main functions

Objective

Design and construction of a tensile creep test bench on polymer and composite specimens.

Problematic Issues

Creep tests should be in accordance with ISO 899-1 (determination of creep behaviour – tensile creep).

The machine must be capable of performing very long duration tests (several months), on several specimens simultaneously. The loads applied are highly variable and the tensile test cannot be performed using masses.

The measurement of deformation requires a very high resolution measuring device, independent of the temperature of the thermal chamber.

Solution and Result

The equipment designed by our teams is a creep and tensile test bench.

Each test specimen is clamped between 2 flanges. Reference rules are fixed on the side of the flanges. The assembly is fixed between the frame and a load cell.

In a creep test, the cylinder is controlled by the force measurement of the load cell. During a tensile test, it is controlled in speed and position.

The thermal chamber consists of a mobile part allowing access to the test specimens. This oven is temperature controlled by a PT 100 probe.

The measurement of deformation is ensured by a high resolution optical extensometer, capable of measuring through the glass of the thermal chamber. This system has an automatic real time calibration system on reference rulers positioned along the specimen. The optical vision assembly is located in a closed compartment of the frame.

The system is controlled by an internal PC, using software developed in LabView. The control system is designed to ensure continuity of testing even in the event of a power failure.

The creep and tensile test bench is used to determine the behaviour of the specimens.

This test bench also allows classical tensile tests to be carried out at high speed.

Products tested

Specimen

A specimen is a test sample. The specimens tested on this creep test bench are made of plastic fibre composite. They are standardised

Test specimens for tensile-compression testing machine

Standardised specimens for all types of material.

Thermal enclosure

Automatic room temperature control using forced-air technology.

Closed creep test bench

Open creep test bench

Typical creep curve

TENSILE CREEP TEST PIECE

Creep test in progress

OUR KEY TEST BENCH FOR THESE TESTS MBFL CREEP TEST BENCH

This bench enables tensile and compressive creep tests to be carried out on one or more specimens, in a temperature-controlled enclosure (up to +250°C).

The force is applied by an electric cylinder controlled by a strain gauge sensor.

The elongation measurement can be given by the digital position of the cylinder or a high-resolution digital camera extensometer system.

This creep test bench can also be used to carry out conventional tensile tests at high speed.