Composite materials have proven their applicability for various structural components. Excellent properties of glass fiber reinforced plastic (GFRP) Composite materials have presented GFRP Composites for potential applications in aerospace and automobile-related industries. Drilling is an important operation for Composite structures during final assembly. This paper investigates the factors affecting delamination in GFRP Composite during the drilling process. Drill speed and feed rate are selected two parameters affecting delamination during the drilling process. The response surface methodology approach has been used for experimental design and analysis of variance. Delamination was evaluated at the entry, middle, and exit positions of the hole. An attempt has been made to optimize the speed and feed rate for minimization of delamination at the three positions using grey relational analysis. The results of this work will help in selecting an optimum level of speed and feed rate to minimize delamination at the entry, middle, and exit positions of the hole to improve quality of the drilled hole.

The laminate Composite plates are a candidate to delaminate when subjected to stresses concentration during the drilling operation. In this paper, the influence of drill feed rate and diameter in the delamination of Composite plates is studied by experimental tests. For this purpose a carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP) plates with different thickness are made in laboratory and drilling is done for the 54 different drilling condition cases. Based on digital images processing (DIP) for the drilled surfaces, an image of the damaged area was used to measure the delaminated area and then compare the results. Optimum feed rate is obtained as 200 mm/min for CFRP and 125 mm/min for GFRP with the spindle speed of 800 rpm. By increasing the thickness of the Composites, there is a decrease in the delamination, so that by increasing the thickness of the CFRP and the GFRP to 4 mm, with increasing diameter of the drilling tool, the area of the damage region in the same feed rate has decreased. In most cases, a directly proportional relationship was confirmed between an area of damage region and the feed rate.

A Composite radome is a durable structure to protect telecommunication radar antennas against mechanical and environmental factors. Due to its placement in front of the antenna and the possibility of affecting the received and transmitted waves, in addition to the mechanical properties, the electromagnetic properties of this structure are very important. In this study, the mechanical properties (tensile strength in the direction of fibers) and the electromagnetic properties (dielectric constant at X-band frequency) for a GFRP Composite radome has been studied and optimized. For this purpose, two types of glass fibers E and D series, and two types of epoxy resin and polyester resin have been used. In addition, three common methods of Composite fabrication including hand layup, vacuum bag, and vacuum infusion have been used. Also, by using the Taguchi test design method and signal-to-noise analysis, the optimal composition was obtained for each of the properties, which for tensile strength of the combination of E series glass fibers and epoxy resin and vacuum bag fabrication method, the highest tensile strength was 320. 9 MPa and for the dielectric constant of D series glass fibers and epoxy resin and vacuum bag fabrication method with the lowest value of 2. 85 were determined. After determining the optimal composition for each of the properties, the optimum state was investigated by considering all the mechanical and electromagnetic properties factors together by using the multi-response optimization method (gray relation). Finally, a combination of D-series glass fibers, epoxy resin, and vacuum bag fabrication method was proposed.

Design of bridge deck with long-term strength, durability and permanence is a significant interest for engineers. One applicable solution to this challenge could be via using hybrid system consisting of conventional materials such as concrete and steel with FRP plates which is also known as Composite deck. Since these deck are relatively new so their performance is not completely known. The present study is dedicated to Composite deck consists of a steel core and GFRP plates. This Composite sandwich bridge deck system is composed of wrapped hybrid core of GFRP grid and multiple steel box cells with upper and lower GFRP facings. The structural performance of deck was evaluated by nonlinear finite element method and numerical results have been compared with available experimental results where possible. After ensuring the validity of numerical modeling of Composite deck, parametric studies such as change in geometry, steel core shape and mechanical properties of materials have been done. It was found that failure mode of the proposed hybrid deck was more favorable because of the yielding of the steel tube when compared with that of absolute GFRP decks. Increasing the thickness and changing the steel core geometry can improve the ultimate load capacity of the deck. The grid layer has the maximum thickness among the GFRP layers and therefore ultimate load capacity of the deck enhanced by increase the elastic modulus of grid layer.

Some of existing concrete structures have some deficiencies due to low material quality or design. In recent years, the retrofit of nonresistant or damaged reinforced concrete members with external bonding of fiber-reinforced-polymer (FRP) laminates has received considerable attention. The objective of this study is to examine effects of glass-fiber-reinforced-polymer (GFRP) Composite rehabilitation system on the reinforced concrete beams. Experiments were conducted on beams with and without GFRP Composite sheets on their tensile surfaces. A total of 16 beams were tested. 8 beams were tested under static loading, while the remaining 8 beams were subjected to cyclic loading.Specimens were 200*300*2000 mm reinforced concrete beams with enough transverse reinforcement to avoid shear failure. The main parameter in the test study was the number of layers of GFRP laminates. The experimental results show that, bonding GFRP laminates improves both flexural capacity and stiffness of beams. Moreover it reduces the quantity and width of cracks, and limits the destruction in rapture zone. Evaluation of load-deflection curves shows the favorite behavior of strengthened beams under cyclic loading. Results of different tests have very good agreement with the application of analytical equations.

A new Composite column composed of pultrusion, concrete, and Fiber-Reinforced Polymer (FRP) is presented in this paper. The confinement and Composite action between the constituent materials result in the enhanced compressive strength and ductility of the proposed Composite columns, compared to traditionally reinforced concrete columns. Compared to other materials, advantages of FRP products include light weight, high specific strength, corrosion resistance, and low maintenance cost. This research showed that I-shaped pultruded Glass Fiber-Reinforced Polymer (GFRP) could satisfactorily improve the structural performance of concrete columns. The effectiveness of discrete and continuous Carbon Fiber-Reinforced Polymer (CFRP) wrapping arrangements for pultrusion-concrete Composite short columns subjected to axial compressive loading is assessed in this study. The experimental program is composed of one series of Composite columns with discrete wrapping arrangements and one series of fully wrapped Composite columns. A numerical model was developed to predict the behavior of the FRP-confined Composite columns subjected to axial compressive loading. The damage mechanisms of the columns wrapped by the Composite layers are strongly dependent on the chosen materials. The results of finite element models are compared with the data obtained from the conducted experimental program, which showed good agreement between the results and the experimental data.

The aim of this study is to investigate the fatigue behavior of GFRP Composite with biaxial fiber orientation [0,90] under different stress levels. First, the tensile test was performed and the UTS value was 420 MPa. Then, fatigue test was performed at 4 stress levels of 70, 50, 42 and 35% of UTS. Fatigue results had acceptable dispersion and the fitting curve on the data also matched well. Finally, the fatigue failure structures of 70 and 35% of UTS samples, using scanning electron microscopy (SEM) were evaluated. The results showed that in both 70 and 35% samples, the mechanism of pull out fibers was obsvered but its intensity was higher in 35% sample. Also in the 35% sample, significant distortion was observed which was absent in the 70% sample. On the other hand, the brittle failure of matrix was more pronounced in the 70% sample than in the 35% sample. This can be related to the increase of the matrix softness due to the application of cyclic load.

Most of ordinary bridge decks are made of reinforced concrete and often deteriorate at a rapid rate in rough operational environments. The rapid deterioration of the deck often impacts other critical components of the bridge. Another disadvantage of the concrete deck is its increased weight in long-span bridges. Therefore, it is essential to examine new materials and innovative designs using hybrid system consisting conventional materials such as concrete and steel with FRP plates which is also known as Composite deck. Since these decks are relatively new so it would be useful to evaluate their performances in more details. The present study is dedicated to Hat-Shape Composite beam with concrete slab. The structural performance of deck was evaluated by nonlinear finite element method and numerical results have been compared with published experimental results where possible. After ensuring the validity of numerical modeling of Composite deck, parametric studies has been done; such as using steel rebar in concrete slab, changing the angle of webs of Hat-Shape Section, modeling RC sections to match strength and stiffness of Hat-Shape Composite beam and altering the GFRP Material into steel and aluminum. It was found that the behavior of this type of Composite beams can be considered with numerical methods without executing costly experiments. Using rebar in concrete slab can increase ultimate load capacity of Composite beam by 45 %. Also strength-to- weight ratio of the beam increased by changing the GFRP Material to aluminum by 51%.

BACKGROUND AND OBJECTIVE: The congenital anomaly of nose is the one of causes of cosmetic of face and repair of this defect is very difficult. In this article, it was reported a case of congenital hypo plastic nasal alar with failure in operation two times. CASE: A 19 year old female referred with hypo plastic nasal alar who had been already operated two times with a failure in repairing this defect. A Composite graft from ear with suitable size was inserted in the defect area of nose and it was improved. CONCLUSION: For repairing this anatomical defect and decreasing failure, this new surgical method is suggested.