Non-contact process control using the pulse-echo method for monitoring the curing of fibre-reinforced plastic components

Grasse Zur Composite Testing develops together with DLR e.V. a non-contact process control using the pulse-echo method as part of a ZIM research project funded by BMWi. Due to the increasing networking of control and plant systems, real-time information on the curing process is of increasing interest in the processing of fibre-reinforced plastics.

The GZ US-Plus® non-contact process control system has been successfully represented on the market for about twenty years. Compared to competing methods such as di-electric analysis (DEA), it has the advantage of being able to measure without direct contact to the manufactured component. The ultrasonic-based system uses a piezo sensor to emit sound waves that are received by a second sensor. A computer calculates the curing process from the running time. This method of process control is particularly important for the aerospace industry, since no holes have to be drilled into the moulds and thus the elaborately machined surfaces of the closed moulds are not damaged.

The limitations of the previous reference technology become apparent in the case of rotor blades of wind turbines. These components are manufactured in open-mold construction and are nowadays up to 80 m long. Under the often harsh production conditions, it is not possible to measure the curing in transmission by means of two sensors (transmitter and receiver). Practical experience shows that only a permanently installed sensor system, which does not hinder but supports the workflows in production, can be implemented in production.

For this reason, the development of OPtimus® was initiated, in which the curing control is realised by means of a coupled transmitter-receiver unit using the pulse-echo method. This technology eliminates the need for a second sensor, which is why the sensor system can remain permanently integrated in the mold. This enables both an enormous increase in efficiency during curing and a guarantee of networking within the scope of QA. Flow front detection is also the current development status, which is expected to be ready for the market in 2022.

Contact

Grasse Zur Composite Testing GmbH, Dr. Fabian Grasse, fabian.grasse@grassezur.de, +49 30 7790791-50

DLR e.V., Hakan Ucan, hakan.ucan@dlr.de, +49 531 295-3709



Webinar “Test methods for determining the intralaminar shear properties of FRP”

In cooperation with Composites United the webinar “Test methods for determining the intralaminar shear properties of fibre-plastic composites” took place on 19 May 2020. Dr. Fabian Grasse went into detail about the characterisation of the shear properties of FRP.

Various test methods have been established for determining the intralaminar shear properties of FRP. These differ in the geometry of the test specimens and the type of load application, which means that different testing devices are used. This webinar will introduce the most widely used standards for the determination of shear characteristics (DIN EN ISO 14129, DIN EN ISO 20337, ASTM D5379 and ASTM D7078) and go into detail about the various advantages and disadvantages of the respective test methods.

Link to the webinar



New at Grasse Zur Composite Testing

The strain gauge connection kit GZ DMS-2/3 is used together with universal testing machines. It is used to connect the strain gauge of the specimen to the testing machine. For this purpose, a Wheatstone bridge is required to record the small ohmic resistance changes that occur locally in the strain gauge when the specimen is strained. In the universal testing machine these resistance changes are converted into strains.

 

 

The strain gauge connection kit GZ DMS-2/3 is characterised by a very user-friendly design. It consists of two or three long-life connection terminals for connecting the strain gauges in 2-wire or 3-wire technology, which guarantee reliable contacting of the strain gauge conductors. The cable to the testing machine is connected to the strain gauge connection box via an Amphenol socket. For the Wheatstone bridge, high-quality and selected supplementary resistors are used. The strain gauge connection box is attached to the frame of the universal testing machine via magnetic feet.

Further information



This year, we are again exhibiting at the internationally most important leading trade fair for fibre-reinforced plastics and composites. The JEC World takes place from 03 to 05 March in Paris. You will find us at the joint stand of Composites United in Hall 6 / Stand F85 + G85.
Arrange an appointment online today!

 

 

You can get a free ticket here. The invitation code is ENV629613576. You are welcome to forward this newsletter or the link to interested colleagues.

This year we would like to inform you about the latest developments of our testing services at the exhibition. In particular our accreditation according to ISO 17025 and the transit to the current version will be in the foreground. In addition, the fair will focus on our online process control GZ US-Plus, which has been successfully used for over twenty years and is the only process control on the market capable of contactless measurement.

We look forward to your visit!



Product development partner

Code Product Solutions is an international, independent provider of engineering and consulting services. The company provides solutions for products made of plastics, composite materials and metals. Code Product Solutions relies on accurate computational simulations for mastering challenges long before the first prototypes become available. Reliable material measurements are essential for their approach.

Composite materials

The complexity of the mechanical behavior of composite laminates also means that characterisation is difficult. Therefore, Code Product Solutions works closely together with Grasse Zur Composite Testing to obtain accurate measurement data for non-linear anisotropic material models with failure behavior.

Read more [PDF]



Get in touch with us at Composites Europe 2019

This year, for the first time in seven years, we are not represented with our own stand at Composites Europe. Nevertheless, you have the opportunity to speak personally on site with the Grasse Zur Composite Testing team about material testing on fibre-reinforced plastics, testing services in our ISO 17025 accredited testing laboratory or reference test fixtures such as the picture frame. Simply select an appointment from the list. You will then receive a confirmation email.

We are looking forward to a personal conversation!



Werkstudent

Copyright Federal Institute for Materials Research and Testing (BAM) 2014

We are happy to carry out material tests on fibre-reinforced plastics for you in our ISO 17025 accredited test laboratory, even during the summer break. So you can go on holiday with peace of mind and the test results will be on your desk afterwards. Our experience shows that the number of incoming orders increases considerably after the summer holidays, which can lead to delays in order processing. Therefore we would like to give you some references in own thing:

  • The Grasse Zur team does not take company holidays and is always available for you during the summer.
  • Incoming orders are processed in the order in which they are received. For this reason, it is advantageous to place an testing order even if the material to be tested is not yet available. This allows us to better schedule the tests and procure the necessary aids in good time, such as ordering strain gauges.
  • We are always at your disposal for all questions concerning composite testing.

Contact us simply and without obligation, we will be happy to advise you!



Grasse Zur Composite Testing exhibits at the 10th International Thermoset Conference in Iserlohn.

The reference technology for online process control GZ US-Plus will be presented at the symposium for thermosetting materials and fibre-reinforced plastics. The symposium will take place from 08.-09.05.2019 in Iserlohn.

Further information:

Process Control



Fatigue tests at a special price

 

 

As a follow-up to the JEC Paris 2019 we offer you a special price for fatigue tests to determine S/N curves. You will receive a discount of 25 percent on the corresponding tests if you order before May 17th 2019. The tests take place in our accredited testing laboratory:

  • Tests under various load conditions, e.g. R = -1 (alternating tensile/compressive load), R = 10 (compressive/compressive load) or R = 0.1 (tensile/tensile load)
  • Testing with calibrated servo-hydraulic universal testing machines (MTS)
  • Execution of quasi-static preliminary tests to determine the strength
  • Sinusoidal load type with peak value control (force or displacement)
  • Test frequency as a function of the load horizon
  • Test specimen production (CNC milling) and measurement with calibrated measuring devices
  • Application of strain gauges for R = 0.1 on request
  • Preparation of detailed test reports including the S/N curve, the straight line according to Basquin and the stress/cycle number curve in a semi-logarithmic diagram.
  • Sending of raw data in CSV format on request

The tests can be implemented promptly. Just contact us, we will be happy to make you a personal offer!



The entire Grasse Zur Composite Testing team congratulates Olympic Bobsleigh Champion Mariama Jamanka (Oberhof) on her double victory in Whistler! One year after her sensational triumph in Pyeongchang, she crowned herself World Champion for the first time. At the title fights in Whistler, Canada, the 28-year-old won the gold medal on Sunday with pusher Annika Drazek.

We are proud to be able to test for the Institute for Research and Development of Sports Equipment (FES), without whom this victory would certainly not have been possible!


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