Papers by Keyword: Elevated Temperature

Abstract: This paper presents a series of experimental studies on the behaviour of engineered cementitious composites (ECC) under quasi-static and high strain rate loads. Potential enhancement of ECC to the resistance and ductility of structural members was evaluated under column removal scenarios and impact loading conditions. Besides, dynamic increase factors for compressive strength and critical strain were derived according to experimental results under high strain rates. Finally, conclusions and recommendations were made in accordance with the use of these materials for different structural performances.

Abstract: This paper is focused on clarifying behaviour of concrete at elevated temperature with employing new test set-up constructed at Institute of Building Construction and Technology, Vienna University of Technology. This unique test set-up allows measuring gas permeability of different building materials such as concrete or ceramic at both high temperature (up to 400°C) and pressure (up to 6 bars). Present paper illustrates a new set up for permeability measurement during the heating and cooling and different testing procedures and evaluation of their influence on results.

Abstract: This paper presents the results of an experimental investigation on mechanical characterization of adhesive T-joint in granulator fluidization bed at elevated temperature. This research aims to explore the suitability of adhesive bonding between stainless steel plate and perforated plate to replace plug weld in granulator fluidization bed. For this purpose, T-joint and bulk specimens were prepared for tensile loading tests, at different temperature. Measurement of the temperature-dependent of the tensile strength was conducted using thermostatic chamber attached to a universal testing machine for a range from room temperature to 100°C. The strength of adhesive T-joint decreases for temperatures over than 35°C. This is because at high temperature, the failure is determined by the changes of mechanical properties of adhesive. The results have shown that the strength of adhesive T-joint was affected by both temperature and bondline thickness. The objective of the present study was to examine a series of adhesively-bonded T-joints in tension at elevated temperatures between room temperature and 100°C having various bond thicknesses.

Abstract: In this study, an experimental investigation was conducted in order to determine the effect of moisture absorption at different adhesive thickness (i.e., 0.5, 1.0, 1.5 and 2.0 mm) on strength of adhesive T-joint in urea granulator fluidization bed. In particular, T-joint specimens were exposed to three humidity conditions, namely, 80°C, 90°C, and 100°C at a constant time immersion of 15 minutes in water. Stainless steel plate and stainless steel perforated plate were joined by using a specific adhesive jig according to desired thickness. Tensile test was conducted by using universal tensile machine (UTM) at room temperature. The result obtained has enabled to explain the failure mechanisms and characteristics of adhesive T-joint with respect to moisture condition and bonding thickness. Epoxy adhesive with several weight percent of water absorption will degrade the physical properties of the adhesive. Moisture condition has some effect on the strength of the adhesive bonding. 1.0 mm of adhesive thickness provides the highest value of failure load. Experimental results indicated that failure load of adhesive T-joint at room and 90°C water temperature give higher value of strength if compared to water temperature at 80°C and 100°C.

Abstract: The paper discusses the crushing behavior of glass fibre reinforced epoxy (GRE) pipes under hydrothermal ageing condition. This study determines the behavior of the GRE pipes when subjected to different ageing periods and temperatures. Hydrothermal ageing has been found to cause degradation between resin and fibre interface thus causing the reduction in the strength of composite laminates. The pipes were subjected to hydrothermal condition to simulate and precipitate ageing by immersing the pipe samples in water at 80°C for 250, 500, and 1000 hours. Compression tests were carried out using Universal Testing Machine (UTM) for virgin condition and aged samples in accordance with ASTM D695 standard. The maximum force at the initial failure region is observed for each of the conditioned pipes. The results show that the strength of the matrix systems was considerably degraded due to the plasticization of the matrix system.

Abstract: In this study there was found that ionizing beta radiation increased the strength of bonded joints and improved the adhesion properties of polycarbonate (PC). Bonded joints at elevated temperature (60 °C) were tested. Generally, for the formation of quality bonded joint it is important to wet the adhesive bonding surface well. Wettability is characterized by the contact angle of wetting. The liquid has to have a lower surface energy than the solid in order to be able to wet the solid substance. The measurement results indicated that ionizing beta radiation was a very effective tool for improvement of adhesive properties and increased the strength of bonded joints of PC at elevated temperature (60 °C). Bonded surfaces with ionizing beta radiation doses of 0, 33, 66, 99, 132, 165 and 198 kGy were irradiated. The best results were achieved by irradiation at doses of 66 kGy by which the highest surface energy and the highest strength of bonded joints of PC were achieved. The strength of bonded joints after irradiation was increased up to 10 % and surface energy up to 30 % compared to untreated material.

Abstract: This paper investigates the finite element modelling of the temperature distributions of reinforced concrete slab using a general purpose non-linear finite-element program, ABAQUS. The reinforced concrete slab is tested under exposure to designed fire in order to validate the shell element in in the ABAQUS program. The modelling results showed agreement with the fire test and it demonstrated that the ABAQUS shell element can be used to predict fire behaviour within reinforced concrete slab in elevated temperature conditions.

Abstract: Electromagnetic acoustic transducers (EMATs) has overcome many disadvantages of the traditional piezoelectric ultrasonic sensors and can be applied in elevated temperatures and on-line inspection. In an EMAT testing system, the tested material and EMAT itself make up a whole system. So the performance of EMAT is closely depended on some physical parameters of tested material. On the other hand, characteristic parameters of metallic materials are closely related to temperature, such as density, modulus of elasticity, electrical conductivity and magnetic permeability. As the temperature increases, the density of the metal material is reduced, the elastic modulus is reduced, the electrical conductivity is decreased, the magnetic permeability has a consistent increasing trend until the Curie point. Thus the EMAT detection performance affected by the change of temperature should be considered. This paper studied the effects of temperature on EMAT testing. Three materials of 20 # steel, Q235 and 16MnR were investigated. Testing temperature varies from 26 °C to 500 °C. The results show that under elevated temperature condition, EMAT echo signals still have a good waveform and stability. Meanwhile, signals are attenuated less than 2dB. It proved that the EMAT technique has a good steady performance in elevated temperature.

Abstract: Adhesive bonding is a joining technique that offers great design flexibility as it can be effectively integrated into practically available industrial sequences of single-piece work. Adhesive is seldom used in high-temperature structural applications that exposed to extreme environment, particularly in the granulation application. Granulator fluidization bed is a main component of urea granulator system in fertilizer plant. Perforated plate and frame structure are normally joined together using plug welding techniques. However, this technique has been proven unreliable. Plug welding technique requires specific amount of heat and welding speed to avoid excessive metal melting (304L Stainless Steel) due to a thin perforated plate, i.e. 1.25 mm. Moreover, fluidization bed is exposed to operating temperature of 95°C. This research aims to examine adhesively-bonded T-joints in tension at temperatures between room temperature and 100°C. This is also to identify the effective bond thickness at different temperatures by testing specimens with various bond thicknesses. The experimental result obtained used for validation by FE model of adhesive T-joint.

Abstract: The paper discusses the crushing behavior of various winding angles of glass fibre reinforced epoxy (GRE) pipes at elevated temperatures. Two different winding angles of composite pipes were chosen for the study; ± 55°, ± 63°. GRE pipes angled ± 55° and ± 63° are compressed using Universal Testing Machine (UTM) at room temperature and elevated temperatures of 45°C, 65°C, and 95°C according to ASTM D695-10 standard. The temperatures were chosen based on the glass transition temperature (T_g) that was measured earlier. The results show that as the temperature is increased, the compressive strength significantly degraded. This is due to the change in the properties of the GRE pipe from a rigid state to a more rubbery state as the composite pipe reached T_g. GRE pipe with winding angle ± 55° show a higher compressive strength compared to ± 63°.