Understanding how wing geometry and internal structural configuration influence vibration behavior is essential for ensuring the aeroelastic stability and structural integrity of modern aircraft. This study presents a comprehensive numerical investigation of the modal and deflection characteristics of aircraft wings with different geometries (symmetric tapered planform and swept-back) and spar configurations (box and I-section) using the finite element method (FEM) in ANSYS Mechanical APDL R.15. Six NACA airfoil profiles (0024, 2411, 2416, 2424, 4412, and 4421) with angle of attack 9° under 50 m/s speed and 1,100 kg pay load were analyzed under identical aerodynamic and material conditions using linear elastic and small-deformation theory. Aerodynamic coefficients were determined using thin airfoil and Prandtl’s lifting-line theories, while modal parameters were extracted through high-order 20-node solid brick elements and verified through mesh convergence analysis. Based on the results obtained, the tapered wings show a natural frequency nearly 22% higher than swept-back wings. The matter that confirms the dominant influence on geometric stiffness. On the other hand box spar wings reveal 9.5%–22% higher frequencies but showed 20%–30% higher deflection than I-section spars, demonstrating their superior torsional compliance and enhanced energy absorption under the dynamic effect. On the contrary, I-section spar resulted in higher bending stiffness and lower deformation, especially in higher-order modes. Based on airfoil series, the more the thick NACA 0024 as well as 2424 profiles revealed the highest levels of stiffness, based on 6 th mode frequency that exceeded 250 Hz, but the thinner cambered sections like NACA 4412 and 4421 exhibited compliance and limited rigidity against torsion. Based on the findings, the obtained increase in the natural frequency and the reduced deflection with stiffer geometries reflect improved resistance to aeroelastic instability like flutter onset. A statistical analysis using ANOVA verified that the geometry of the wing has a statistically more significant effect on modal response than the spar type although both have a significant influence on vibration behavior. Furthermore, the result of analysis concludes that the taper wings reinforced with spars type I-section give the most balanced combination of weight efficiency, stiffness and stability against vibration for the aircraft type medium payload.
The loose sand is subject to large settlement when it is exposed to high stresses. This settlement is due to the nature of the high drainage of sand, which displays foundations and constructions to a large danger. The densification of loose sandy soils is required to provide sufficient bearing capacity for the structures. Thus soil stabilization is used to avoid failure in the facilities. Traditional methods of stabilized sandy soil such as fly ash, bituminous, and cement often require an extended curing period. The use of polymers to stabilize sandy soils is more extensive nowadays because it does not require a long curing time in addition to being chemically stable. In this study, the effect of adding different percent
... Show MoreOne of the goals of adding adjuvants to agricultural spray solutions is to enhance the droplet size characteristics of this spray. Droplet size, in turn, has an influence in the deposited spray quality, in addition to the drift and losses of spray to off-target places. The aim of this research was to evaluate the effect of adding adjuvants to two types of water from different sources on the droplet size characteristics. Two types of adjuvants were employed in the tests: the active substance content of the first adjuvant was a 50% aqueous solution of sodium salt of alkylbenzenesulfonic acid—10% (HY), whereas the second was from rapeseed oil (natural origin)—85% (OL). Both adjuvants were tested in two concentrations: the first was
... Show MoreA study carried out in quail’s field owned by the Department of Animal production/ Collage of Agriculture / Tikrit University. For the period 14/ 5/ 2016 to 4/ 6/ 2016 in order to study the effect of adding Curcuma longa - to the diet of quails - on some productive and physiological characteristics of the Japanese quail birds bred for meat production. Using (48) quail birds which are two weeks old provided by Department of Agricultural Research. The birds were divided randomly after weighing them into three treatments; four replicate treatments for (4 bird/ replicate). The treatments as follows: (T1) control group (fed diet without any supplement), second (T2) and third (T3) groups were fed diet supplemental 4.5 and 9g Curcuma powder /
... Show MoreThe style of Free-form Geometry (FFG) has emerged in contemporary architecture within the last three decades around the world through the progress of digital design tools and the development of constructive materials. FFG is considered as the hard efforts of several contemporary architects to release their products from familiar restrictions to discover new and unfamiliar styles under the perspective of innovation. Many contemporary architects seek to recognize their forms and facilitate dealing with according to specific dimensional rules. The main research problem is the lack of knowledge, in the field of architecture, in previous literature about the formation processes in achievin
Grass carp at a weight of 34.68 + 2 g were gradually exposed to four saline concentrations: tap water (0.1), 3, 6, 9, and 12 gm/litter, and the first concentration represented a control treatment. Fish were fed on a diet with a protein content of 30% for ten weeks. Results of the growth experiment showed that the feed conversion rate was 2.46, 3.58, 4.84, 6.77, and -8.56 in the first to fifth treatments, respectively, and the rate feed conversion efficiency was 40.65, 27. 93, 20.66, 14.77 and 11.68 %, while the protein intake was 22.38, 20.44, 18.86, 17.47 and 16.56 g in salt concentrations of 0.1, 3, 6, 9 and 12 g/L, respectively. In another experiment to study the effect of salt acc
Background: Fixed orthodontic appliances impede the maintenance of oral hygiene and result in plaque accumulation leads to enamel demineralization caused by acids produced by bacteria. Studies on plaque control strategies in orthodontic populations are limited. This might be caused by difficulties in the quantitative evaluation of dental plaque because the teeth have various levels of bracket coverage, and different tooth sizes and malocclusions, making the traditional categorical indices complex. The present study aims to evaluate the effect of different hygiene protocols on plaque quantity on bands with different attachments. Materials and method: Twenty patients had four bands within the orthodontic appliance. Then randomly divided into
... Show MoreA factorial experiment was applied with four replicates on rosemary plants (Rosmarinus officinalis L.) grown in pots inside the glasshouse of the Department of Biology, College of Science, Salahaddin University, Erbil, Iraq, during April, 2019 to July, 2020, to determine the effects of soil moisture content ( SM1: 100% and SM2: 60% field capacity), nitrogen fertilizer (N1: 100, N2: 200 and N3: 300kg/hectare), and magnesium fertilizer (Mg1: 0.0, Mg2: 30 and Mg3: 60kg/hectare) and their interactions on some growth characteristics and essential oil content of rosemary plants. Two cuttings were taken from rosemary shoots (on March, 2020 and July, 2020) after 12 and 15 months of planting respectively. Results showed that cutting 1:
... Show MoreThe general approach of this research is to assume that the small nonlinearity can be separated from the linear part of the equation of motion. The effect of the dynamic fluid force on the pump structure system is considered vibrates at its natural frequency but the amplitude is determined by the initial conditions. If the motion of the system tends to increase the energy of the pump structure system, the vibration amplitude will increase and the pump structure system is considered to be unstable. A suitable MATLAB program was used to predict the stability conditions of the pump structure vibration. The present research focuses on fluid pump problems, namely, the role played by damping coefficient C, damping factor
... Show MoreBackground: Adjustment of any premature occlusal contact of any zirconia restoration requires its polishing or glazing in order to restore the smoothness of the restoration. The objective of this in vitro study was to evaluate the effects of different polishing systems and glazing on the surface roughness of full-contour zirconia. Material and methods: Forty disks (diameter: 8 mm, thickness: 6.4 mm) were prepared from pre-sintered full-contoured zirconia block; they were colored and sintered in a high-temperature furnace at 1500ËšC for 8 hours. The specimens were then leveled and finished using grinding and polishing machine and adjusted using diamond disk. The specimens were then randomly divided into four groups (n=10), group I involves
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