List of Articles
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Open Access Article
1 - Fabrication, Testing and Analysis of Composite Lattice Panels Under Three-Point Bending Load
Mahdi Farhadi Ali Davar Mohsen Heydari Beni Jafar Eskandari JamThanks to their high strength-to-weight ratio, lightweightness, and excellent energy absorption, composite lattice panels can be used in the aerospace, marine, automotive, and other industries. These structures can be used as an alternative to string-reinforced structur MoreThanks to their high strength-to-weight ratio, lightweightness, and excellent energy absorption, composite lattice panels can be used in the aerospace, marine, automotive, and other industries. These structures can be used as an alternative to string-reinforced structures, honeycomb (core) sandwich panels, and aluminum grid structures. In this paper, a composite lattice panel is first fabricated from glass/epoxy by hand lay-up method using a silicon rubber mold. In this method, a Kagome composite lattice panel with twelve layers of resin-impregnated fibers was fabricated during a continuous process. After fabrication, the test panel was shown under three-point bending and failure modes. Also, a numerical simulation of three-point bending was performed in ABAQUS software. Then, the simulation results were compared with those of the experimental test, indicating a good convergence between the experimental test results and the finite element ones up to the point of failure. Due to changes in directions of force, these structures have a high ability to withstand damage, and therefore, continue to withstand the load after the failure of one or more ribs. Also, there is no sudden and sharp drop in the load-bearing capacity of the structure despite the force being maximized, which can be attributed to the high energy absorption of such structures. Instead, the force decreases slowly with fluctuations, and the structure continues to absorb energy until final failure. Therefore, such lightweight structures can be used in applications where energy absorption is of great importance. Manuscript profile -
Open Access Article
2 - A Quasi-Analytical Method Algorithm Development in Redesigning the Geometry and Structural Analysis of An Aircraft Propeller and Comparing with the Finite Element Method
Behrooz Shahriari Hassan Izanlo Nedasadat SeddighiThe aircraft propeller is effective in the performance of the aircraft propulsion system and must have acceptable structural strength. The complex aerodynamic geometry of the propeller makes its analysis more difficult. In this study, dynamic and aerodynamic stresses ar MoreThe aircraft propeller is effective in the performance of the aircraft propulsion system and must have acceptable structural strength. The complex aerodynamic geometry of the propeller makes its analysis more difficult. In this study, dynamic and aerodynamic stresses are calculated using the Finite Element Method (FEM). A structural analysis algorithm based on the quasi-analytical method is developed to evaluate the finite element analysis. In this regard, first, an algorithm is developed to redesign the propeller which performs in a way that by checking the dimensions, the geometry of the quasi-propeller is determined with the same mass and the coordinates of the center of mass. Then, different algorithms are developed to calculate the distribution of mass, moment of inertia, and the cross-section of the quasi-blade geometry. The calculation algorithms of rotational dynamic and aerodynamic stress distribution are developed. The results show that the FEM and the quasi-analytical method are well matched. In this study, the force equivalent to the thrust and the opposite force to the propeller rotation are placed instead of the aerodynamic pressure distribution. The comparison of the results obtained from the quasi-analytical method and the FEM indicates that the overall maximum stress of the system occurs at the root of the propeller and the maximum net stress due to aerodynamic forces occurs in the middle of the propeller geometry. According to the results, the rotational dynamic stress is much higher than the aerodynamic stress. It is also shown that the aerodynamic stress reduces the overall stress of the system. Manuscript profile -
Open Access Article
3 - Investigating the effect of nanosilica on the compressive strength of hard concrete by considering Atomic Force Microscopy (AFM) examinations
seyed mohammad mahdi shafiei mahboobeh pirizadeh Ebrahim ZolgharneinThis study investigated the compressive strength of hardened concrete and the formation of Calcium Silicate Hydrate (C-S-H) with the addition of nanosilica (SiO2). Compressive strength testing was performed using ASTM C496 to determine stress-strain curves and compressi MoreThis study investigated the compressive strength of hardened concrete and the formation of Calcium Silicate Hydrate (C-S-H) with the addition of nanosilica (SiO2). Compressive strength testing was performed using ASTM C496 to determine stress-strain curves and compressive strength of the materials. The hydration process and formation of C-S-H and Calcium Hydroxide (CH) was examined using Atomic Force Microscopy (AFM) and Fourier Transform Infrared Spectroscopy (FTIR). Results indicate an increase in compressive strength using 1, 3 and 5% of nanosilica to concrete replacement by volume in comparison to the control mix (without nanosilica). The optimum concrete replacement to yield maximum strength was of the 5% nanosilica content. Comparing the 56 day results for the 3 and 5% of nanosilica replacement samples, notice the same percentage of C-S-H formation of 83 and 85%, respectively Manuscript profile -
Open Access Article
4 - Numerical and Experimental Investigation of Natural Frequency and Damping Coefficient of Flexible Cellular Lattice Structures
M. R. Karamooz-Ravari Amir Hosein Samimi Reza DehghaniCellular lattice structures encompass a class of metamaterials characterized by the arrangement of interconnected struts and/or plates, offering an adaptable microstructure that enables a broad range of property control. These structures have garnered significant attent MoreCellular lattice structures encompass a class of metamaterials characterized by the arrangement of interconnected struts and/or plates, offering an adaptable microstructure that enables a broad range of property control. These structures have garnered significant attention for their distinctive properties and have found widespread application across industries such as aerospace, medical, pharmaceutical, automotive, defense and safety. This study seeks to explore the impact of geometric parameters on the natural frequency and damping coefficient of cellular lattice structures. Samples featuring BCC and OCTET architectures with varying porosities were initially produced using fused deposition modeling (FDM). Subsequently, both experimental and numerical analyses were conducted to assess the first natural frequency and damping coefficient of these materials. Comparison of the numerically obtained results with experimental data revealed a strong agreement. The findings indicate that, for both BCC and OCTET lattices, an increase in porosity is associated with a decrease in both natural frequency and damping coefficient. Manuscript profile -
Open Access Article
5 - Nd:YAG laser processing of thick NiTi wires to locally alter transformation properties towards achieving multiple memory shape memory alloys
Mahmoud Kadkhodaei Amin Alipour Ehsan ForoozmehrEvery commercial NiTi (Nitinol) Shape Memory Alloy (SMA) has its own transformation temperatures, which may cause limitations in ever-growing demands for the application of these alloys in novel engineering design. Among various methods proposed to achieve multiple func MoreEvery commercial NiTi (Nitinol) Shape Memory Alloy (SMA) has its own transformation temperatures, which may cause limitations in ever-growing demands for the application of these alloys in novel engineering design. Among various methods proposed to achieve multiple functional characteristics, laser processing offers effective solutions in locally controlling the transformation properties of NiTi parts. The current work describes the application of laser technique followed by post processing to locally alter transformation temperatures and impose phase transition for thick NiTi wires. To this end, various laser parameters are applied, and the influences of peak power and pulse width on the functional, microstructural and mechanical properties of laser processed samples are studied. A four-sided laser processing protocol is proposed to process almost the whole cross section of thick Nitinol wires. It is also shown that post-processing heat treatment is required to recover the shape memory properties of as-processed Nitinol specimen. The transformation temperatures of final processed Nitinol wire increase by about 50 °C compared to those of the unprocessed base material. Manuscript profile -
Open Access Article
6 - Numerical Motion Analyzing Based on Recorded Empirical Data by Smartphone Features
Bahador Abolpour Yaser TaghipourAbstract: This study presents a new method to analyse the motion of moving objects. The novelty of this study is that the presented work obtains your location based on the coupled measured data using the GPS and other motion sensors of a smart phone. This method can be MoreAbstract: This study presents a new method to analyse the motion of moving objects. The novelty of this study is that the presented work obtains your location based on the coupled measured data using the GPS and other motion sensors of a smart phone. This method can be used for GPS free navigations in future studies. The smartphone sensors measure the desired values and a developed Android application records this data. A developed MATLAB code analyses these values for car road travel using multiple coordinate transformations and removes the effects of Earth's gravity from the measured acceleration. It is recognized that the presented method can be used to analyse the movement and performance of the studied material. The obtained results show that the integration of data recorded by the accelerometer sensor integrates the effects of noise and this sensor is not a convenient feature to obtain the instantaneous location. Calculating the acceleration using GPS data may also not be accurate in this case. Getting the location and acceleration using a GPS sensor and accelerometer is more accurate. Manuscript profile