Papers by Keyword: GLARE

Abstract: This study investigates the impact resistance of Glass Laminate Aluminum Reinforced Epoxy (GLARE) composite laminates by incorporating shape memory alloy (SMA) wires. The influence of varying percentages of pre-strain (0%, 1%, 3%, and 5%) on the SMA wires embedded in the GLARE composites was examined. Laminate composites were made by hand lay-up method using 1100 series aluminum, glass laminate, epoxy resin, and nitinol wire. Impact testing was carried out using the Charpy (un-notched) method. The results demonstrate that the presence of SMA wires significantly enhances the impact resistance of the laminates. The energy absorption capacity of the laminates was found to increase with increasing pre-strain percentage. The highest impact resistance was observed in the specimens with 3% pre-strain, which exhibited a 35.2% increase in energy absorption compared to the specimens without SMA wires. However, a further increase in pre-strain to 5% resulted in a 21.5% decrease in energy absorption due to the higher fraction of stress-induced martensite, limiting the shape memory effect. Additionally, the damage analysis revealed that the absence of SMA wires led to severe debonding and delamination in the GLARE laminates. Conversely, specimens with 3% pre-strain exhibited the least damage, with limited debonding observed only in the front interface of the aluminum and epoxy-laminated fiberglass layers. The higher damage resistance of these specimens is attributed to their optimal energy absorption capability. Based on the findings, it is recommended to further investigate alternative shape memory alloy materials to determine their impact resistance enhancement potential compared to the current SMA wires. Additionally, conducting experiments with pre-strain percentages in the range of 3-5% would provide a better understanding of the maximum achievable performance. Furthermore, microscale observations should be conducted to gain more detailed insights into the damage mechanisms of the tested specimens.

Abstract: Fiber metal laminate (Glare) made of 2014-T6 aerospace aluminum alloy sheets adhesively bonded with E-glass fiber based composite prepregs is investigated in the paper. The fabrication procedure of the laminate is explained. Chemical composition, macrostructure and residual stress of aluminum alloy are obtained. Mechanical properties of the laminate viz. tensile, flexural and shear strengths are measured.

Abstract: The Fiber metal laminates (FMLs) combine the advantages of fiber-reinforced polymer properties, like stiffness and strength, with metallic alloys, like toughness and durability. These hybrid materials can unravel some problems in the industrial sector, particularly in aerospace, and advanced automotive industry. Still, there are significant challenges in the GLARE sheets forming process even for small drawing ratios, notably smaller and complex-shaped fiber metal laminate with low thickness. As a case study, a cylindrical GLARE cup was chosen. This shape with sharp bends and vertical geometrical features, still face many challenges and difficulties in the forming process. Numerical simulations have been used utilizing ABAQUS and compared with the experimental results in the Hydro-mechanical deep drawing to achieve good forming quality with higher depth. An extensive investigation of the effect of process variables has been done such as cavity pressure, blank holding force, and blank diameter. Also, their roles in wrinkles formation, tearing and thinning, and formability has been performed. Furthermore, the friction in two cases; cured, and semi-cured condition, has been considered. The results show that the application of cavity pressure within specified limits has a positive effect on the quality of the formed cup and leads to higher depths. The same conclusion for the blank holder, which has a positive impact on wrinkling elimination and friction reducing between the aluminum layers and the fiberglass. The result shows that the semi-cured condition of the GLARE has a good effect on wrinkling reduction, due to the uniform movement of the fiberglass inside the aluminum layers. Understanding these parameters and the GLARE forming behavior and have a good selection of these parameters can give the advantage to achieve smaller and more complex shapes with higher depth, particularly for mass production. Finally, this study can extend the industrial application areas of FMLs and GLARE parts.

Abstract: Visually impaired people primarily rely on their remaining vision. Unfavorable lighting conditions can further hamper this remaining vision. In this context, the present contribution mainly focuses on the evaluation of the visual performance of visually impaired and normally sighted individuals under different lighting conditions. To investigate the visual performance empirically, we developed a test involving different adaptation luminance values. A monitor with adjustable brightness facilitated various tests to determine the visual performance as a function of the adaptation luminance and glare. In addition, the subjective impressions of the visually impaired participants were captured via interviews. The study included 98 visually impaired people and 38 people without eye-related ailments. The interview results suggest that most people with visual disabilities require special lighting conditions. An increased lighting requirement is observed amongst 50% of this group. Moreover, 75% of this group display increased glare sensitivity. Likewise, adaptation problems and critical issues related to non-uniform lighting are manifest. Visually impaired individuals display significant in the visual performance variance at different brightness levels. Individuals with eye disease display a greatly reduced contrast threshold and a higher subjective level of discomfort compared to individuals with normal vision. Most visually impaired individuals require a higher degree of brightness to achieve their maximum personal visual performance. About a quarter of these individuals achieves the optimal visual performance at lower brightness, while displaying an increased sensitivity to glare. In general, glare has a decisive influence on the visual performance of visually impaired people. For general lighting purposes, a predominantly indirect lighting source better accommodates these individuals' requirements.

Abstract: Crashworthiness is one of the requirements for design of aircraft to ensure the safety of passengers on aircraft. With increasing applications of advanced composite in aircraft structures, study on the crashworthiness of composite fuselage is desirable and important. For this purpose, this paper investigates the influence of composites on crashworthiness of fuselage section. Firstly, model of fuselage section of aircraft is established. Skin, frame, stringer and stiffener are made of the composite T800/QY8911 or GLARE. Then, the crash responses subjected to vertical impact velocity of 9.14m/s are analyzed. The acceleration history is recorded for assessment of the crashworthiness. In addition, the deformation process and failure mode of composite fuselage section are analyzed. Results indicate that the frame made of brittle composite may fracture in the crash process, which leads to serious damage to the fuselage. While the frame with good toughness can maintain the integrity of fuselage, thereby protecting passengers.

Abstract: In this work we investigated the application of a novel high performance polymer, polybenzoxazine, as a polymeric matrix in Fiber Metal Laminates (FML). This polymer, when applied on the development of FMLs, generated higher mechanical properties in comparison to fiber metal laminates obtained with epoxy. To investigate the mechanical performance of the polybenzoxazine matrix in FMLs, a mechanical behavior comparison was carried out among epoxy matrix laminates - glass fiber reinforced aluminum laminate (GLARE) and carbon fiber reinforced aluminum laminate (CARALL) - and FML constructed with aluminum and carbon fiber reinforced polybenzoxazine. The mechanical properties were characterized by drop weight impact and flexural methods, and the polybenzoxazine curing behavior through differential scanning calorimetry (DSC). Polybenzoxazine FML generated increasing of: 18% of maximum load, 11% of maximum elongation under flexure and 7.5% of impact energy absorption compared to other fiber metal laminates.

Abstract: The primary focus of this investigation is to determine the distribution of thermal residual stresses that result during composite bonding processes, and the effect on stresses generated during the subsequent cold expansion of holes. Residual stress measurements were carried out using neutron diffraction techniques. Results show that the cold expansion process resulted in radial compressive stresses 3-4 mm from the edge of the hole and there was no significant effect of thermal residual stresses from the bonding process on the cold expansion and bolted stresses.

Abstract: Specularity removal is useful for image related applications that need consistent object surface appearance. For a single image it can be more challenging problem due to presence of different shapes, sizes and colors of specular regions, which may have some parts with totally missing data. The problem can become more difficult if the specular regions having partial information grow bigger, because the exact boundaries are difficult to mark. Any region filling method can provide unusual results because the appropriate boundaries selection is important for these methods. In this work, we address this problem and propose a scheme which can handle specular regions by segmenting both types of sub-regions of specularity. Our segmentation algorithm is multistage which uses Luminance as well as principal components for the identification of specular regions. For specularity removal, we proposed a three step scheme which includes balancing illumination, inpainting and blending. Finally feed-forward neural network is proposed to estimate the tunning parameters, which not only automate the whole process but also simplifies the difficult task of choosing parameters like size of specular regions or preprocessing selection. The results demonstrates the effectiveness of the proposed method for a variety of images having natural specular reflection.

Abstract: The artificial lighting level and visual comfort of drivers for a high-speed train cab are evaluated by using computer simulation technology. The simulation model is established first, and then some lighting quality indexes, such as illuminance, illuminance uniformity and glare, are analyzed based on related design standards. Considering the effects of environmental lighting on drivers physiology and psychology, the analysis on environmental psychology for driver of the cab are conducted also. The evaluation method proposed in the paper is significant for improving artificial lighting design of high-speed train cab.

Abstract: This paper proposed a new method of describing street glare. Glare is a typical light environment, it is affected by streetlights and street surface conditions. It impact on street safety. This paper based on survey of Tianjin, Changsha, Zhengzhou street area, included optical lights types, height of light bulbs, distance between tow lights, street surface brightness, illumination and other factors examination and record. Survey date had been used to set 36 street lighting simulated models and compare with the calculation. The output for the analysis is a series of maps reflecting the relationship between street glare environment and its factors. The case study proved that street lighting environment is closely associated with streetlights bulbs brightness and its installation site. The results show that high level of light brightness will lead to high level of glare and higher light bulbs will increase glare.