Showing 8 results for Glare
Volume 10, Issue 2 (9-2020)
Abstract
Background: Human comfort involves their physical, psychological and mental comfort. There are several factors that may affect human physical comfort; among them luminous, acoustic and thermal comfort can be mentioned. Usually in researches done in the field of human physical comfort, researchers tried to predetermine human perceived comfort by measuring some physical factors, whilst there are also other ones that can affect human comfort and are necessary to be considered.
Aims: The aim of this paper is to determine the non-physical factors that affect human physical comfort. Another aim is to achieve the model of human physical comfort affected by non-physical factors.
Methods: In this paper by conducting a library research, researches done in the field of non-physical factors that affect human physical comfort were investigated and analyzed; in this way that physical comfort evaluation methods for users of a space, factors affecting it, places in which those researches were done and those researches results were classified and analyzed. In this paper, among factors that can affect human physical comfort, luminous comfort, acoustic comfort and thermal comfort were studied. Analysis method was statistical and by modeling charts and defining oriented trend process in previous researches.
Findings and Conclusion: Findings of this paper indicated that human physical comfort in a space can not be predicted only by relying on physical factors that were usually used in comfort-related indicators.
Volume 10, Issue 3 (10-2020)
Abstract
Aims: Daylight has a great impact on the quality of indoor spaces, especially educational spaces. In educational spaces, visual comfort along with the use of daylight is of great importance. Therefore, the purpose of the present study is to evaluate the visual comfort in the classrooms.
Methods: Two indexes of illumination (lux) and Glare (DGP) were investigated to evaluate the visual comfort in 9 classrooms of 3 faculties from Polytechnic University of Shahrood. Attempts were made to examine at least one sample from each geographical direction. Cases were simulated in Grasshopper software via Honeybee plugin and then analyzed.
Findings: The evaluation of the Illumination (lux) index showed that only the class 2 in Mechanical Faculty was in accordance with Standards and in terms of DGP index, class 1 in Engineering Faculty was annoying at 10 and 14 o’clock in February. In the rest of the classes, the glare was due to reflective light and inappropriate lighting angle.
Conclusion: The results of the analysis showed that in the current situation, by making change in the spatial location of variables such as seats place and white board location relative to the position of windows, we can control the shading and better use of shades and light situations and can greatly improve the lighting quality of interior spaces. Also, the most important finding of the research is that the interior design of the space to create the connection between the light source and the layout and white board is not done by experts or is left to uninformed people.
Abbas Masoudi, Gholamhossein Lighat, Mohammad Hossein Pol,
Volume 14, Issue 7 (10-2014)
Abstract
This paper investigated experimentally and numerically the effect of nanoclay on ballistic impact behavior of GLARE. The prepared GlARE is made of two Aluminum 2024 facing sheets and E glass/ epoxy/nanoclay as nano composite core. Nano composite section has been composed of undirectional E glass 409 g/m2, resin CY 219, hardner HY 5161 and nanoclay closite 30B dispersed into the epoxy system in a 0%, 4%, 7% and 10% ratio in weight with respect to the matrix. All panels fabricated using laid-up method in fiber weight fraction of 60%. Ballistic tests were conducted using Gas gun at the velocity of 205 and 225 m/s. The results of the ballistic impact experiments show that the amount of Specific energy absorption variations in 4% of nanoclay content is insignificant. However, in nanoclay contents of 7% and 10%, the Specific energy absorption increases. In other words, it be concluded that nanoclay has positive effect on higher percentage on the ballistic impact. The 3D finite element (FE) code, LS-DYNA, is used to model and validate the experimentally obtained results. A noticeable correlation was found between experimental and numerical results.
Pooya Pirali, Mehrdad Ghadami, Reza Babaei,
Volume 17, Issue 3 (5-2017)
Abstract
The medium caliber armor piercing projectiles, commonly being used against armored and aerial targets, have high kinetic energy and in practice, it is impossible to prevent these projectiles from penetration through different types of targets. So this is essential to demonstrate a solution to repel these projectiles by studying on behavior of the targets. In this study, numerical simulation of oblique penetration of medium caliber armor piercing projectile through the flat targets of GLARE3 2/1 and GLARE5 2/1 has been investigated by ABAQUS finite element software, and using explicit-dynamic solver. 625m/s and 1250m/s strike velocities and 0, 30, 45, and 60 degree strike angles have been studied. Damaged area have been investigated. To verify the solving method, an experimental equation, which has determined the penetration energy of a thin GLARE target, has been used. Results have shown that some special phenomena (e.g. asymmetric petalling, and small-cracks formation) appear when penetration occurs obliquely. This is also has been shown that lower strike velocity, and higher strike angle will result in higher target damage. Furthermore, delamination of target has been investigated.
Masoome Haghani, Behrouz Kari, Rima Fayaz,
Volume 17, Issue 4 (6-2017)
Abstract
Windows, as elements connecting built and natural environment, play an important role in providing internal comfort. During winter, solar heat gain through windows reduces heating demand, heating load and energy consumption of the building. On the other hand, it increases cooling load in summer. Hence, using blinds is common in office buildings to control solar radiation. Although using blinds prevents from entering part of the solar radiation, simultaneously, it improves comfort conditions for the employees. It should be mentioned that an appropriate control of blinds, regarding changes in external and internal environmental conditions, will lead to a decrease of energy consumption and discomfort caused by direct solar radiation. In this paper, the use of blinds on windows is simulated for cardinal orientations and different blind angles and positions; finally, the total thermal load of the space and the amount of glare is studied. According to the results, blinds have a significant impact on spaces total load, as well as reduction of interior glare compared to the reference case with no blinds.
Mohammad Ekrami, Hamed Ahmadi, Mohammad Bayat, Hadi Sabouri,
Volume 17, Issue 7 (9-2017)
Abstract
In this paper, drop weight impact tests using projectiles with different nose shapes on GLARE 3 are examined experimentally. GLARE targets are made of two aluminum sheets and six composite layers by hand lay-up method. The composite layers are constructed using unidirectional E-glass fiber and cy219 resin with adding hy5161 as a hardener. The projectiles are manufactured in flat, hemispherical and conical 90̊ nose shapes and hardened. The projectiles collide to targets with initial impact energies of 40, 55 and 70 Joule. In this study, the effects of nose shape at the maximum impact force, the penetration, the energy absorption, and damage zone are examined. The results show that conical projectile in all three impact energies and hemispherical projectile at 55 and 70 Joule fully penetrate targets. Under impacts of the flat projectile, a shear plug is formed on the upper face of targets and a plastic deformation is created on the bottom face of targets in impact energies of 40 and 55 Joule. For hemispherical projectile at 40 Joule and for flat one at 70 Joule, the tensile stresses in the aluminum sheet located at the bottom face of target result in longitudinal crack. Moreover, results show that the maximum and minimum contact force and energy absorption are occurred in the projectile with flat and conical nose shapes, respectively.
Parviz Ghasemi, Omid Rahmani,
Volume 18, Issue 8 (12-2018)
Abstract
Impact damage is one of the most important failure types for aircraft structures, which can come from variety of reasons. Such impacts can realistically be predictable for the duration of the life of the aerospace structure and can cause internal damage that is often challenging to identify and can produce rigorous drops in the strength and stability of the structure. By combination of monolithic Aluminum alloys with composites, structures will be achieved that has weight lighter than monolithic aluminum alloys and better fire and fatigue resistance. These structures, that called fiber metal laminates, are developed as a suitable alternative to monolithic aluminum in aerospace structures. In this research, impact resistance of multi-walled carbon nanotubes (MWNTs) /glass aluminum reinforced laminates (GLAREs) is investigated at variety concentrations of 0.1, 0.2, 0.3 and 0.5 wt% of MWNTs. Here, anodizing method is used for preparation of aluminum surface. The results showed that by adding MWNTs to GLAREs, energy dissipation is increased in charpy impact test. Investigation showed maximum energy dissipation at 14.36% in 0.3 wt% of CNTs. Also different fracture modes observed for different concentration of carbon nanotubes.
Mojtaba Dehghan, Fathallah Qods, Mahdi Gerdooei, Hamidreza Mohammadian Semnani,
Volume 21, Issue 6 (5-2021)
Abstract
The aim of this study is to improve the strength properties of glass-aluminum multilayer hybrid composite using AA1050 aluminum sheets processed by the accumulative roll bonding (ARB) process. Also, the effect of different cycles of ARB process on the strength properties of hybrid composite has also been investigated. At first, the ARB process was applied on the AA1050 sheet. Afterwards, the microstructure and tensile properties of the ARB deformed sheets were investigated. Then, the ARB processed AA1050 sheets were used to make glass reinforced aluminum laminate (GLARE). In the end, the tensile properties of the GLARE composite were examined. By the progress of the ARB process, the hardness and strength of the sheet increased. The elongation of the first cycle processed specimens dropped drastically. But, by increasing the process cycles, the elongation increased gradually. The use of the ARB processed aluminum sheet in the manufacture of GLARE composite significantly improved the tensile strength of the GLARE. In the GLARE made of annealed aluminum, most of the elongation of the aluminum layer occurred after the breaking of the glass fibers and in conditions outside the GLARE composite; as a result, the reduction of the sheet elongation during the ARB process caused the simultaneous failure of the metal layers and the glass fibers during the tensile test of the GLARE. Hence, this event did not reduce the ductility of the composite. In other words, the total energy absorption and fracture toughness of the aluminum layers occurred when the GLARE had not failed.
