THERMOELASTIC AND ELASTOPLASTIC EFFECTS MEASURED BY MEANS OF A STANDARD THERMOCAMERA (original) (raw)

Introduction to thermoelastic stress analysis

Strain, 1999

The theory of thermoelastic stress analysis is reviewed and the assumptions in developing the theory are assessed. The temperature relationship for an isotropic material under plane stress conditions equipment for thermoelastic stress analysis is based on infra-red detection systems. The commercially available

Thermoelastic stress analysis based on infrared thermography

2012

A new concept of visual and virtual instrumentation based on infrared analysis of thermoelastic stress is presented in this paper. The parts of the construction where the highest tension occur are determined by the thermal analysis. It is predicted by installing devices for measure the level of strain suffered by excavator construction. Combining thermal imaging techniques with measurements using a measuring tape tension, the great benefit in maintaining these structures can be achieved. Thermal imaging analysis gives a general picture of the distribution of tension. Examined the structure on which the measuring tape to measure the intensity and possible direction of tension action. The TSA also helps to make a numerical analysis faster and in a predictable manner, without need for extensive iterative investigations, what reduces both time and costs. In this paper are shown results of thermal analysis wheel excavator construction.

Infrared thermography to evaluate thermoplastic composites under bending load

Composite Structures, 2015

Thermoplastic matrix-based composites are becoming ever more popular due to their many advantages over both metals and thermoset matrix-based composites. In particular, they can be tailored by the addition of a compatibilizing agent to the matrix, which allows to create a multitude of materials. Of course, each of these materials requires characterization for an appropriate exploitation. In this context, infrared thermography represents a viable inspection means since it is non-contact, non-intrusive and can be used to monitor the entire existence of a product, from its manufacturing process to completion as well as inservice life. In this work, several composite materials based on a polypropylene matrix, which may be neat, or modified by addition of a certain amount of a specific compatibilizing agent, and reinforced with glass, or jute, woven fibres are considered and subjected to cyclic bending tests. Infrared thermography is used for monitoring the bending event.

Infrared Thermography to Monitor Thermoplastic-matrix Composites Under Load

Infrared thermography is used to monitor thermal effects, which develop when a material is under load (impact, or bending) and which may be useful to get information about the laden material behaviour in view of assessing the material performance. Different types of specimens are considered involving either a pure polypropylene matrix, or a modified polypropylene (by addition of a compatibilizing agent based on maleic anhydride) and either glass, or jute, fibres as reinforcement. The tested glass reinforced composites are subjected to either impact tests, or bending tests, while the specimens enclosing jute fibres are only exposed to bending tests. The obtained results show that, for any type of specimen and test, the use of an infrared imaging device is advantageous to visualize the thermal signatures, which are indicative of the damage occurring under load.

Study of selected thermoplastics using dynamic mechanical analysis

MATEC Web of Conferences

The aim of given paper is to study selected polymers using dynamic mechanical analysis method (DMA). DMA is one of the most useful techniques for the study of the viscoelastic behaviour of thermoplastic polymers. In relation to DMA, an oscillatory stress and strain is applied to the material at specific frequencies and temperatures and based on this mentioned fact hereinbefore, the resulting changes after the loading in the material are measured. This technique allows detecting the melting temperature and the glass transition temperature of the thermoplastic materials. Furthermore, some spectroscopy techniques, such as energy dispersive X-ray spectroscopy (EDX) and infrared spectroscopy (IR), were also used for the investigation of the thermoplastics. The thermoplastics used for examination, namely polyethylene, polystyrene, polypropylene and polyethylene terephthalate, were gained from the waste of the packaging.

Infrared thermography for non-destructive evaluation of thermoplastic composites

2014

Infrared thermography (IRT) is used to get information on the behavior of thermoplastic matrix composites under low velocity/energy impact. Indeed, infrared thermography proved already its usefulness in the investigation of impact damaging of composites, as both surface thermal mapping when the specimen is being impacted and non destructive evaluation technique. However in the past, IRT has been mainly used with thermoset matrix composites, while the attention of the present work is focused on composites with a thermoplastic matrix. Several specimens are considered involving two types of matrix: pure polypropylene and a modified one with addition of a compatibilizing agent based on maleic anhydride. A quite different behaviour is found for thermoplastic composites with respect to thermoset ones in terms of both the reaction to the impact event and the occurred damage. Besides at high impact energy values, the behaviour of the two types of matrices is completely different.