حمیدرضا زارعی

Wood has some limitations in properties and applications due to its natural nature, which need to be modified. Wood modification is usually done with different aims and methods. One of the wood modification methods is thermal treatments in order to improvement of dimensional stability and biological resistance. But, it is surely affected on physical and mechanical properties of wood. Wood thermal modification in presence of oxygen causes the oxidation of its chemical structure which leads to decrement of physical and mechanical properties. Therefore, elimination of oxygen in thermal modification can reduce its destructive effects. In current study, the effect of thermo-oil process on the function of white rot fungus has been investigated. Moreover, the effect of this process on engineering properties of birch and pine wood species was evaluated.

In this study, two wood species of birch (Betula sp.) and pine (Pinus sp.) cut into the desired timbers. Heat treatment of the prepared timbers was carried out in a cylinder which equipped to the pressure and vacuum system. Also, industrial recycled oil was used for heat treatment of the timbers. The temperature and time treatment were considered 195 °C and 5 hours, respectively. At the end of the process, the used oil was drained into the oil storage tank and the timbers were removed from the cylinder after applying vacuum. In order to investigation of biological resistance as well as physical and mechanical properties (water absorption and swelling, density, mass loss, bending strength, compression strength parallel to the grain and impact strength) test specimens were prepared from the treated and control timbers based on the standard. The SPSS software was used for statistical analysis. The results were statistically analyzed based on a One-Way ANOVA method.

Results revealed that thermo-oil treatment can reduce the functionality of white rot fungus and also its efficiency on physical and mechanical properties of both wood species. Moreover, the results showed that this process improved the physical properties and reduced the mechanical properties, except compression strength parallel to the grain.

Thermo-oil treatment at high temperature causes structural changes of wood and affects its physical and mechanical properties. Also, the structural changes caused by heat treatment can be an effective and inhibiting factor to functionality of white rot fungus on physical and mechanical properties of wood.

In this article, to investigate the severity of damage to the helicopter pilot under the crash impact, the numerical simulation of the actual helicopter cockpit seat has been done. To limit the complexity of the problem, a fully vertical impact was considered as a reference scenario for the assembly consisting of a collapsible helicopter seat, an energy absorption section, and a humanoid dummy. For this purpose, the three-dimensional model of the chair in the laboratory was studied in two states with and without the addition of the energy absorption mechanism. A honeycomb structure was used in the seat cushion section. The results of the research showed that the use of UPVC damper to test the crash impact with a certain mass based on biomechanical criteria, an average 80 % decrease in serious injuries to the skull and spine has been achieved. Also, based on the results obtained in this research, although the aluminum honeycomb structure meets the criterion of damage to the head and is within the permissible range, it has rejected the criteria of damage to the spine and permissible acceleration range. However, compared to the case without honeycomb, it has performed much better and has been able to absorb the energy of the crash impact.

In this article, Low-Pressure Injection Molding (LPIM) method was investigated as a method for forming zirconia (zirconium oxide) parts. It is one of the methods used for manufacturing engineering ceramics with complex shapes and high dimensional accuracy. In this method, a binder composition (paraffin waxe) is used as the plasticizing agent to shape zirconia particles. Optimizing the volume percentage of solid load helps to make parts without defects. For this purpose, in this research, two ways of investigating the behavior of flow behavior and debonding of zirconia feedstocks were used to select the optimal percentage of solid load. This optimization was done between feedstocks containing 52, 53, and 54 Vol% of solid load and at temperatures of 70, 80, and 90 °C. The feedstock containing 54% solid load has better flow behavior and less sensitivity to shear, as well as better debonding behavior than the other two feedstocks, and it was possible to make the part without defects through this feedstock.

Nowadays, flying objects engines are harmed and malfunctioned due to aging phenomenon. One of the most important problems lies in the hot part of these engines. Turbines of these engines have creep and metallurgical difficulties which lead to cracks and part failure. In case of one engine blade failure, the whole engine will be out of operational line. Thus, proposing a method for aging determination and longing the lifetime of these engines’ parts can play a significant role in keeping the military helicopters of the country continuously operating. In this study, Eddy current non-destructive method was utilized to evaluate the microstructural changes of Rene80 super alloy turbine blades of J85 engine. The microstructural changes that occurred in this sample by aging phenomenon at a temperature above 800 ℃ for 1600 h under service was studied through destructive and non-destructive routes. To this end, changes of 4 turbine blade parts which were under service for the same periods of times were compared together as well as with an intact blade sample (as the control sample). Metallography studies, scanning electron microscopy (SEM), EDS element analysis, and micro hardness test were done to assess microstructural changes and destructions and phases characterizations. It was found that there was a good correspondence between the results obtained from destructive studies and Eddy current evaluations. The results show that the volume fraction and grain size of the precipitates of the under-service samples were considerably increased compared to the intact specimen and the morphology of 'γ precipitates were transformed from cubic to spherical shape. Likewise, the hardness of the under-service samples was decreased compared to the intact one. The Eddy current results show that the impedance amount of the under-service samples was decreased compared to the control which is in correspondence with the hardness test results. And the induction resistance parameter in Eddy current test closely correlates with hardness test results (R2=0.95). Altogether, it can be concluded that Eddy current non-destructive method is capable of separating different samples of this super alloy and distinguishing of microstructural changes.

Ground fissuring in Azar Oil Field (AOF) in Ilam Province that almost happening after heavy rainfalls, has been threatening engineering structures like refinery facilities, oil and gas pipelines, oil well cellars, and some access roads. From the geological point of view, AOF is located on the north limb of the Changoleh anticline, composed of the Lahbari section of the Aghajari geological Formation. Sandstone, siltstone, and claystone are the main rock units in the studied area. Sandstone and siltstones are very loose materials with collapsibility potential. Ground fissures are regularly created almost perpendicular to the anticline axis. In this article, in order to evaluate ground deformation mechanism and related ground fissuring, engineering geological investigation has been used in a company with Radar interferometry technics. Radar interferometry studies using time series analysis based on PS-InSAR technics on two data sets using the Sentinel-1A dataset including 68 images from 2014 to 2020 show that ground deformation in the Azar oil field occurs with two different patterns. Linear and permanent deformation in the northwest of the Changoleh anticline which is in direction with anticline axis and plunging. The other deformation that occurs in the southeast of Changoleh anticline is a nonlinear and periodic deformation with intervals of 5 to 6 years. This deformation occurs with heavy rainfalls in the region. This research reveals that ground fissures in AOF are a consequence of ground deformation related to the enlargement of the Changoleh anticline and collapsing of loose sandstones of the Aghajari Formation.

In this article, Low-Pressure Injection Molding (LPIM) method was investigated as a method for forming zirconia (zirconium oxide) parts. It is one of the methods used for manufacturing engineering ceramics with complex shapes & high dimensional accuracy. In this method, a binder composition (paraffin & industrial waxes) is used as the plasticizing agent to shape zirconia particles. Different parameters such as temperature, pressure & injection time, mold temperature, etc. have been found to be effective in shaping the ceramic parts based on this method. Throughout this research, these parameters were examined, & their optimal values were obtained. The optimal injection temperature was in the range of 80-90 Celsius degree, injection pressure in the range of 3-5 bar, & injection time in the range of 10-15 seconds to form a crucible with the size of 130×85×75 mm (height×internal diameter×external diameter). This study also examined the FESEM images of the microstructure of parts in the injected, debonded, & sintered bodies. According to the findings, the zirconia crucible in this article shows notable similarity with the crucible made by Zircoa company with the code 3001 in terms of physical properties such as bulk density & apparent porosity.

The purpose of this study was the interpretive structural model of factors affecting the development of talent identification system in beach soccer in Iran with a structural-interpretive approach. The research method is descriptive and applied in terms of purpose. Research data were collected in the field and in a mixed manner (qualitative and quantitative). The statistical population in the qualitative section was 18 experts and in the quantitative section was 104 prominent managers and coaches of beach soccer in the country. Due to the limited membership, the community became equal to the sample. The research instrument was a researcher-made questionnaire containing 19 factors affecting the establishment of the talent identification system, the validity of which was confirmed by 10 professors of sports management at the university and its reliability was confirmed by Cronbach's alpha test (α = 0.85). Documentary review, expert opinions and Delphi technique were used to identify the factors and interpretive structural modeling method was used to design the model. Findings showed that 19 factors affect beach soccer talent identification and the factor model was obtained at six levels. Factors to increase research and development as well as the quantitative and qualitative development of talented trainers were placed at the infrastructure level. The development of research in talent identification, quantitative increase and improvement of the quality level of beach soccer coaches will facilitate the implementation of the talent identification model and the establishment of talent management in beach soccer in the country.

Beach soccer is one of the emerging sports that has attracted the attention of most countries in the world. Therefore, it is necessary to consider the development of beach soccer in Iran. Therefore, the purpose of this study was to design an interpretive structural model of barriers to the development of beach soccer in Iran. This research is applied in terms of purpose and data collection was done in the field and in a mixed qualitative and quantitative manner. The statistical population in the quantitative part, including the officials of the beach soccer committee of the federation and the football delegations, the managers of the clubs and the coaches of the national beach soccer teams, was equal to 50 in total and in the qualitative part, 18 experts. Due to the limitation of members, the statistical sample was equal to the community. The research tool was a researcher-made questionnaire containing 16 items which was designed based on a comprehensive study of sources and opinions of the qualitative research sample and using the Delphi method. The validity of the questionnaire was confirmed by 10 university professors and its reliability was confirmed by Cronbach's alpha test (α = 0.88). Barriers were inserted in the form of structural self-interaction and a qualitative sample was provided as a questionnaire. ISM technique was used to level the obstacles and determine the priority of the action. Based on the findings, the obstacles were classified into seven levels. Obstacles to the lack of a development plan and the lack of attention of federation officials and football delegations to the development of beach soccer were at the basic level of the model. In general, it can be said that more attention of the officials of the Football Federation and the delegations on the design and implementation of the strategic plan will facilitate the removal of many intermediate and top obstacles of the model.

The heat treatment process was known as one of the most economical routes for development of the high strength steels. Low alloy AISI4140 steel was also famous for its widespread applications in the automotive and aerospace industries. Thus, a combination of heat treatment procedure and using this type of steel could be the economical and applicable process for various industries. As a result, in the current study, the effect of different heat treatment cycles on the yield and ultimate tensile strength and also elongation per cent of the low alloy AISI 4140 was conducted. All of the samples were heat-treated at 880 ˚C for 30 min to achieve Austenite and then quenched in a diesel fuel environment. To continue, by performing the heat treatment cycles at different conditions for each sample, the martensite, martensite-ferrite, and bainite phases were formed.By performing tensile and hardness tests on each of the samples, the mechanical properties, and with the penetration of 7.62 mm projectile of G3 gun, the ballistic properties of the samples were evaluated.

In this paper the research has been performed on the cross-axis flow Lucid spherical turbine. Three-dimensional steady numerical simulation is used to determine power output and performance of this kind of turbines for low velocities in a channel. The k-ω SST turbulence model is used to perform the turbulent steady flows around the turbine. Further, Bachant and Wosnik's experimental data reported for spherical Lucid turbine, is employed to confirm the simulations. The influence of three effective parameters of blades, including the chord length, the number of blades and the type of airfoil section on the turbine performance are investigated over a range of tip-speed-ratios. It was found that increasing the blade chord length in lower speed tip ratios cause to increase the power coefficient up to %15 compared to the original version. Also, for the turbine with three blades, the best results were obtained by which, the power coefficient increased by 12.5%. Finally, it is obtained that using asymmetric airfoil section for blades has a positive effect on the turbine performance.

Ultra-High molecular weight polyethylene (UHMWPE) fibers are among the strongest and lightest fibers available and are widely used in high-performance ballistic applications. Despite the great advancement of computational analysis in recent years, precise calculations have not been performed to identify the failure of these fibers due to the complexity of the material behavior to impact. In this research, using the most advanced finite element modeling method of composites (Abaqus-Explicit) has been used to study the composite behavior of these fibers subjected to high-velocity projectile impact. Fiber and matrix are designed using solid elements and 3D Hashin failure criterion was used to determine the behavior of the material. Since this criterion is not available in Abaqus, the VUMAT subroutine has been used to implement this criterion. Velocity diagrams and damage evaluation have been reported. To evaluate and validate this method, six samples of Ultra High Molecular Weight Polyethylene (UHMWPE) Composite panels, consisting of 20 and 45 layers, respectively, were experimentally studied by high-velocity projectiles at different velocities. The simulation results are in good agreement with the experimental results.

Beach soccer is an emerging sport and long-term and comprehensive planning is essential for development. Therefore, the purpose of this study was to compile a document on the strategic development of beach soccer in Iran using the SWOT method. The research method was descriptive and in the form of strategic studies. This research was applied in terms of purpose and the information was collected in the field in a mixed qualitative and quantitative method. The statistical population in the quantitative section included prominent beach soccer managers and coaches (75 people) and in the qualitative section, 18 experts. Due to the limited membership, the community became equal to the sample. The research instrument was a researcher-made questionnaire whose validity was confirmed by 10 professors of university sports management and its reliability was confirmed by Cronbach's alpha test (83α =). The findings showed that in beach soccer, there are eight strengths, eight weaknesses, neither opportunities nor threats, and using SWOT analysis, 12 strategies were obtained and prioritized. Development and productivity of human resources, creating an integrated system of talent management and designing and establishing a system of evaluation and performance management, should be a priority for officials.

Cordierite ceramics are ceramics obtained from a combination of aluminum, magnesium, and silicon oxides. Given that cordierite ceramics have properties such as very low thermal expansion coefficient, low dielectric constant, low density, high hardness, low loss ratio, refractoriness, and good chemical and mechanical stability, they can be used for high temperature applications and tool making. In this study, solid-state synthesis method using oxide powders and silicone resin, followed by cold isostatic press (CIP) method was applied to produce cordierite ceramic with uniform density. Phase detection by X-ray diffraction and determination of density, microhardness, flexural strength, and dielectric constant was performed. The results showed that the α-cordierite phase was synthesized with a density of 2.5 gr/cm-3, hardness of 1151.6 HV, flexural strength of 131.4 ± 6 MPa, dielectric constant of 3.15, andloss tangent of 0.0048 in the frequency range of 8-12.5 GHz.

Due to the impossibility of performing destructive tests, the need for new and Non-Destructive Tests (NDT) in this area is strongly felt. In the present study, using the non-destructive method of Automated Ball Indentation (ABI) test method, some mechanical properties of 4340 annealed steel and 7075 raw aluminum and prepared from aged aircraft are determined. To perform calculations related to ABI method, the explicit relations routine was coded in FORTRAN and verified. Then samples of uniaxial tensile test of 4340 annealed steel and 7075 raw aluminum and prepared from aged aircraft are prepared and their stress-strain curves are obtained. Also, ABI tests are performed on 4340 annealed steel samples and 7075 raw aluminum and prepared from aged aircraft and the results of the two methods were compared. The comparison of results showed that the calculated error of yield strength and ultimate strength was less than 9 and 14%, respectively. With increasing force, this value in some areas reached less than 0.7%.

The study is to identify,rank the obstacles to the development of beach soccer in Iran. This research is applied in terms of purpose,data collection was done in the field,in a mixed qualitative,quantitative manner. The statistical population in the quantitative part,including the officials of the beach soccer committee of the federation,the football delegations,the managers of the clubs,the prominent coaches of the national beach soccer teams were equal to 50 people,in the qualitative part,12 experts. Due to the limited statistical population,the statistical sample was equal to the population. The research instrument was a researcher-made questionnaire including 29 obstacles to the development of beach soccer in the country. The validity of the researcher-made questionnaire was confirmed by 10 university professors,its reliability was confirmed using Cronbach's alpha test (α,0,88). The Delphi method was used to identify obstacles to the development of beach soccer,the Friedman test was used to rank the obstacles in the inferential statistics section.The findings showed that 29 obstacles were identified,prioritized in managerial,executive dimensions,areas,facilities,equipment,financial,economic,attitude, support of officials,and human,environmental,respectively. The officials of the federation should first of all remove the obstacles in the field of management,administration,then remove the obstacles of facilities,equipment in their agenda.

In this paper, static strength analysis of superalloy Rene-80 is studied experimentally in both of the coated and uncoated cases. Superalloy Rene-80 is widely used in manufacturing aircraft turbine blades. The service temperature of this alloy is in the range of 760–982 °C. Although this superalloy has good mechanical properties and acceptable protection against oxidation and hot corrosion, it is coated to improve its resistance to surface degradation factors such as oxidation, hot corrosion and erosion at high temperatures. In this paper, penetrating aluminide coatings were applied to this superalloy with two separate methods of penetration-powder and penetration-slurry, respectively, under the brand names Codep-B and IP1041slurry, respectively and the effect of these coatings on the tensile properties of Rene-80 under ehe temperature range of 25-982 ° C was investigated. For this purpose, the samples according to ASTM-E8 standard are produced and after coating (the two methods mentioned above) along with uncoated samples are carried out a tensile testing in accordance with the ASTM-E21 standard. The results of the present study showed that at low operating temperatures, uncoated samples have better tensile strength than coated samples, but this behavior is reversed at high operating temperatures, which indicates the importance of using nickel-based superalloy coatings for extreme heat environments. Also, the model with IP1041slurry coating at high operating temperature has better yield and ultimate strengths than powder penetration coating.

In this paper, the creep strength of Rene 80 superalloy in both uncoated and coated states is studied experimentally. The operation temperature range of this superalloy is 760–982 °C, in order to increase its resistance to surface degradation factors such as oxidation, hot corrosion and erosion at high temperatures, a coating is applied on it and its use without coating is not recommended. In this paper, diffiosion aluminide coatings were applied to this superalloy by two separate methods of pack cemantation and slurry under the brand names of Codep B and IP1041, respectively, and the effect of these coatings on the creep life of this superalloy at 982 °C and metallography is examined by SEM was investigated. For this purpose, samples according to ASTM-E8 standard were produced and after coating along with uncoated samples were subjected to creep test according to ASTM-E139 standard. Control parameters including temperature, stress and service life of uncoated samples are evaluated according to C50TF28 standard. Uncoated creep samples lost their strength after an average of 33 hours and rupture occured. Codep-B coated samples lost their strength after on average of 45 hours and slurry-coated samples lost their strength after on average of 51 hours. The results showed that the coatings increased the creep life of the coated samples compared to the uncoated samples by at least 12 hours.

The preparation, sale, or use of controlled drugs (CDs) require close regulation, and misuse of these drugs can have irreversible side effects. Therefore, the present study aimed to design a web-based system entitled San-Tech for monitoring of CDs.

This is a practical development study carried out to design and establish a program to monitor controlled drugs. The study was performed in three stages. At first, the informational and functional elements of the program were identified through interviews and investigations. In the second stage, they were reviewed and approved by experts. Then, this system was designed using the C # programming language, the server with ASP.NET Core API technology, and the user with Angular technology.

The informational elements required for this system included 70 items in the classes of the patient, drug, prescription, physician, specialty, pharmacy. Nine functions are also considered for this system to apply more control over the use of CDs. The system was designed and available for pharmacies at https://pharmacy.hums.ac.ir.

This system can record some information, including patient and physician details, type and number of CDs, and the time of visit. According to this information, pharmacies, as well as Food and Drug Administrations, could monitor the sale and use of CDs

Composites that withstand high temperatures are one of the parameters that always is the focus of attention. Especially when this type of material in sensitive parts flying craft is used. Generally, sensitive parts of flying craft should be also, radar transparency, have good mechanical strength at high temperatures. PTFE matrix composite is one of the options suitable for this purpose. PTFE is one of the polymers that have high heat resistance and low dielectric constant. This article processing preparation of glass fiber reinforced PTFE polymer matrix composites with conventional sintering methods. Then composite sheets made from E-glass woven fabric with PTFE have been produced with conventional sintering methods. To achieve optimal sintering processing of PTFE matrix composite, various cycles of time and temperature were selected and the optimal sintering cycle for such composite materials is obtained by the design of the experimental method. Then the mechanical properties of composites with different sintering processes were measured. To determine the mechanical properties, a tensile test was performed, and to determine the electrical and electromagnetic properties, a dielectric constant test in X-band was performed. The loss tangent, as well as composite products obtained. The maximum tensile strength and tensile modulus were achieved in this research respectively equal to 130 Mpa and 3.65 GPa. Constant dielectric and Loss tangent of the samples produced in the x-band are 2.37 and 0.096, respectively. Finally, to validate results in this research, the results of the performed tests were compared with the results of other references in this context.

Corrosion is a harmful phenomenon for metals have been utilized in various industries like aerospace. Uniform, galvanic, pitting, intergranular, and crevice corrosions are types of corrosion causing approximately 20% of the whole repairing costs of aircraft. The flying condition alters during the flight results in enormous problems for an aircraft. Several methods have been reported to diminish the corrosion rate in which the protective coatings have been exploited in this assessment. To this end, three-layer coating employed to apply on the steel and aluminum substrates. Middle layer and top coat were similar relating to high-build epoxy and polyurethane, respectively. However, zinc-rich epoxy was applied on the steel substrate and neat epoxy was employed for aluminum for the primer layer. The airless spray was used to fabricate different coating determining 6-24 h for curing of each layer. EIS results illustrated that this coating protective system showed just one-time frequency response after 1000 h immersion in 3.5% NaCl exhibiting the fact that water molecules could not penetrate through the coating and access the substrate after 1000 h. Additionally, the low-frequency response of EIS plots confirmed the excellent anti-corrosive performance of coating system applied on the aluminum. Moreover, the pull-off test clarified the reasonable adhesion strength of the coating system on both aluminum and steel substrates.

Metal/composite hybrid structures, which are a combination of low-density composites with low-cost metallic materials, have significant potential to provide cost-effective energy absorption devices for a variety of applications. In this research, an experimental study was performed in order to investigate the effect of overlapping composite layers on energy absorption and crashworthiness characteristics of aluminum/epoxy hybrid tube reinforced with glass fibers under quasi-static load.  Also, another experimental study is conducted to determine the crash performance of aluminum/composite hybrid tube under static axial crush force. The result is that Hybrid tubes consist of epoxy reinforced with E-glass fiberglass tape overlaps around aluminum tubes with different percentages of overlapping. Quasi-static crash tests are done on aluminum cylindrical and aluminum/composite hybrid cylindrical tubes with 5%, 50%, and 100% overlap and the amount of energy absorption, specific energy absorption, peak crushing force, mean crushing force, crush load efficiency and the percentage of their changes were obtained and compared. Finally, to validate the results in this research, the results of the performed tests were compared with the results of other references and literature in this context.

Cordierite (2MgO,2Al2O3,5SiO2) is one of the compounds in the MgO-Al2O3-SiO2 triple diagram which they have properties such as low dielectric constant and loss tangent, very low thermal expansion coefficient, refractory and suitable chemical and mechanical stability. In this study, α-cordierite was synthesized using the solid state reaction method of oxide powders (aluminum oxide, magnesium oxide and silicon oxide) and MK silicone resin. To investigate the synthesized samples, X-ray diffraction test was performed and showed that α-cordierite is formed at the temperature of 1400 °C. By performing the micro hardness test, it was observed that the hardness of the synthesized α-cordierite is equal to 12.35 GPa. Three-point bending test was performed to evaluate the flexural strength and the flexural strength was 62 ± 3.6 MPa. Also, the dielectric constant of 3.18-3.22 (in the frequency range of 8-12 GHz) and the loss tangent of 0.001-0.005 were obtained for the synthesized α-cordierite.

In order to create a laser beam, one common method is to use beam pumping. In this method, beam is rstly emitted to the active medium of laser crystal and the electrons in the last shell of atoms are stimulated. With some internal interactions, laser beam will be created and some pumping energy is converted to heat in the crystal. In solid-state lasers, large amounts of pumping power may lead to heat generation in the active laser medium and a non-uniform temperature distribution in the crystal is generated. The temperature gradient causes thermal stress in the crystal structure and can be eective on thermomechanical behavior of the crystal and the quality of the laser beam. With increasing the pumping power, the heat generation within the active media is increased and consequently the thermal eects including the thermal lensing, polarization of output beam, mechanical stress, reducing the eciency of output beam, are intensied. Even in this case, thermal stress causes failure. Hence to achieve a high quality beam laser, it is necessary to investigate the thermomechanical behavior of the laser crystal, through the designing of solid state lasers. In the past works, thermomechanical behavior of the crystal was investigated in framework of Fourier heat conduction theory (Heat wave diusion speed is considered to be innite), while this theory is not appropriate to study the heat conduction for medium under pulsed heat with appreciable relaxation time. Hence, in this research, by providing a nite element formulation based on the non-Fourier thermoelasticity (with considering relaxation time), distributions of temperature and stress in the Nd:YVO4 crystal are calculated. The results show that the maximum temperature and stress calculated by non-Fourier theory, are larger than those calculated by the Fourier theory and also the non-Fourier theory predicts lower failure power for crystal. In addition, if the relaxation time is lower than a certain value, the results of classical and nonclassical theories are closely equal to each other.

In this study, the effects of impact of a projectile on a fuel tank are studied using the finite element method and compared with experimental method. Due to penetration of the bullet into the tank, large internal pressures from the fluid are imposed on the tank's walls which can damage it. The considered fluid structure interaction (FSI) problem is solved in an Eulerian-Lagrangian reference frame by using the LS-Dyna software. By comparing of the results obtained from the simulations and the experimental data, it can be seen that the LS-Dyna software is able to model the different phases of event accurately. In previous researches mostly the penetration and cavitation phases are investigated numerically. In this paper all phases namely penetration, cavitation, stresses applied to tank’s walls and bullet exit are investigated. The comparison between the Von Mises stress of walls in the fluid-filled tank and the empty one signifies 30 percent growth of the maximum Von Mises stress in the wall of the fluid-filled tank compared to the walls of the empty tank. Also in addition to what has been done in previous numerical works, the failure mode of fluid-filled tanks are determined numerically. The numerical results show that because fluid-filled tank walls are pre-stress due to the fluid shock waves, the failure mode of fluid-filled tank is quite different with the failure mode of the empty one.

This paper is investigated the effect of impregnation of the high modulus polypropylene shear thickening fluid. Fluid using silica nanoparticles dispersed in polyethylene glycol in both 42% and 44% has been achieved. The penetration tests conducted in this study is in accordance with NIJ 0101-04. The results are evinced that the penetration resistance is improved by impregnation of high modulus polyethylene fibers. This resistance was saliently affected by percentage of nanoparticles dispersed in polyethylene glycol. Whereas by increasing 2% of nanoparticles dispersed in polyethylene glycol (from 42% to 44%), the penetration resistance is increased about 38.9 %. When the carbon Nano tube is inserted in shear thickening fluid, due to reduction of the friction between projectile and target, results decrease in penetration resistance of polypropylene target. When the number of layers is equal, the penetration depth in backing material when 44% impregnated polypropylene fabrics is tested against spherical projectile, is 67.39 percent lower that non impregnated fabrics.