×
The submission system is temporarily under maintenance. Please send your manuscripts to
Go to Editorial ManagerThe human body poses the most important aim for many researchers. In nowadays, the science complex required the involvement of many resources and the coordinated team work of doctors, engineers, and other from the specialists. In the case of dental medicine, due to the nature of teeth material, their dimension and geometrical position, very important problems, like cavities that led to tooth losses. In this study, both the Experimental methods as well as the numerical finite element method have been used to analyze the stress within human teeth under forces similar to those that usually occur during chewing process with different type of food in experimental work. It was manufactured a device Resembling chewing process with vertical movement by converting circular movement into reciprocating. And used DAQ system (strain gauge sensor, DAQ and LABVIEW program) to measure the stress and strain resulted from tooth during the mastication process. Models of Natural lower first molars teeth were collected. All the teeth were cleaned from the soft tissue and stored in saline at room temperature. The teeth were randomly divided into two experimental groups according to the treated cavities shape (class I and class II) each class restored with two type of dental fillings material (Nanohybrid composite and Microhybrid composite), and then strain gauge was bonded at a buccal surface of tooth used. Their installed in acrylic jaws and applied different vertical loads. With used various morsels with different elastic modulus. The stress was calculated at the crown. In numerical 2D model of teeth were created by software Auto CAD (V.14) using wheeler 's data were transfer to ANSYS mechanical APDL (V. 16), subjected load at model similar at that applied at the Experimental work. Class I exhibited the highest stresses compared with class II, in two case Nanohybrid bear stress higher than microhybrid composite. At class I the stress at Nanohybrid is higher than Microhybrid for all morsels by rate (12.96%, 21.48%, 41.8%, 16.56%, 16.86% and 15.74%) at (E1, E2, E3, E4, E5 and E6) respectively, and the stress at Nanohybrid is higher than Microhybrid by almost (36.67%, 45.69%, 47.89%, 34.21%, 41.2% and 165.01%) respectively at the same morsels used at class II. _x000D_ Keywords: , , .
Welding residual stress has influences on fatigue, fracture, and corrosion. It is therefore important to explore the welding factors effect on the residual stresses. In this work, four welding factors (current, arc voltage, welding travel speed and included angle) were used to weld low carbon steel (ASTM A516 Grade 60).The experiments included welding of (60) pieces with dimensions of (300 x 150) mm and 10 mm thickness that were conducted based on the design matrix founded by using design of experiment (DOE) software (DESIGN EXPERT 10) with response surface methodology (RSM) technique. The X-Ray diffraction (XRD) method was used to measure the residual stress, which was then modeled and optimized in terms of the welding factors using (RSM) technique. The data showed that the welding travel speed and arc voltage have a significant influence on the residual stress. It was found that the optimum solution for minimum residual stress was at 450 Amp welding current, 34 volt arc voltage, 38 cpm welding speed, and 60? included angle. Where, the optimum value of residual stress was (-88.4 MPa). Finally, the predicted and experimental results of residual stress were in agreement with a maximum error of 1.8%.
thetic socket, is due to its fiber strength and hardness, and low cost, but there are other more important things which must be considered than these specifications which are1the health1and safety. In this research fiberglass is replaced with monofilament fiber in order to be safe to on makers and users of this socket. In this paper two models of lamination manufacturing have been made and compared in terms of mechanical properties and fatigue life. The first is available and consists of: (4 perlon, 2 fiberglass and 4 perlon), The second is proposed lamination which consists of: (4 perlon, 1 cotton, 1 monofilament and 4 perlon). Simulations were conducted on the made socket made of two types of lamination by using ANSYS 14.5 to show the distribution of stresses, the amount of deformation and less safety factor for both cases. The results show an increase of 42% in the Young's modulus and a decrease in tensile stress and yield stress by 10.8% and 46% respectivel, As for the stress endurance it witnessed an increase of 140%.The simulation results show a decrease in the deformation by 40.7% and an increase in the minimum value of the safety factor of 0.323 to 1.05.
The field of mechanics concerned with studying the propagation of cracks in materials is Fracture Mechanics. Technology systems are meant to withstand the loads to which they are likely to be exposed when in use. Material imperfections arising at the time of production or use of the material are, however, unavoidable and must therefore be taken into account. A stress intensity factor is a fracture parameter that defines the part failure. This paper study’s the effect of cracks on the stresses of rectangular plates having a hole in the center. The plate was subjected to tensile pressure at the top side while maintaining the bottom side fixed. The plate had four cracks distributed around the centered hole at 45o at each side. The effect of the length of the cracks on the resulted stresses and strains was investigated. Also, the effect of the position of the crack on the resulted stresses and strains was studied. Finite element models for the different plate cases were built using ANSYS software. The results showed that increasing the crack length resulted to increase the stresses and strains. The dimension of the plate width, height and thickness were 150 mm, 300 mm and 1 mm respectively, and the crack position was investigated for different crack lengths (5, 10, 15, 20, 25 mm) however the results were not steady as it looks that the crack lengths have changed the stress distribution over the plate.
Most researches have predicted soil erosion of cohesive riverbanks using linear (excess shear stress model) and non-linear (Wilson model) models based on two soil parameters (detachment coefficient, kd, and critical shear stress, ?c) of the linear model and two soil mechanistic parameters (mechanistic detachment parameter, b0, and threshold parameter, b1) of the non-linear model. The goal of this research was to quantify the soil erodibility parameters of Tigris Riverbanks on Nu’maniyah-Kut Barrage reach using linear and non-linear models through the model parameters at three different water contents: dry side, optimum side, and wet side of water contents. Soil samples were collected from three locations south of Baghdad city on Nu’maniyah-Kut Barrage reach of Tigris Riverbanks. Six soil samples acquired from these sites were laboratory tests achieved using a miniature version of Jet Erosion Test device (“mini” JET) to determine the erodibility parameters of both linear and non-linear models. Blaisdell solution (BL) and scour depth solution (SD) were applied to determine (kd and ?c) of linear model from JETs data. Physical soil characteristics; including bulk density, particle size distribution (sand%, silt%, and clay%), average particle size (D50), and angle of repose were reported for six samples acquired from the three sites. The results showed lower value of kd of toe in compared with bank side for some specific sites as observed for both BL and SD solutions of excess shear stress model especially at wet side of water content. No general pattern of ?c related to different water content were observed. The parameters (b0 and b1) of non-linear model have the same behavior of linear model parameters (kd and ?c), but with different magnitude related to different water contents, respectively.
The aim of this study was to support surgeons to decide where to place the screws in order to achieve an optimal fracture healing and to prevent implant failure after a femoral shaft fracture So this paper focus on the analysis of bone-plate construct by using Finite element Analysis (FEA), comminuted femur fractured bone fixed with Dynamic Compression Plate (DCP) 16 holes by 4.5 Cortex screws, to investigate the effects of screws configuration on the mechanical behavior of different seven model as Interfragmentary strain which is the most important factor for femur fracture healing. The results state the relationships between the Von-Mises stress, Total deformation and Interfragmentary strain with respect to the screws configuration. The study shows the regions of maximum stress from stress distribution and also founded that we can decrease the Interfragmentary strain by increasing the number of screws.
Reflective cracking is a serious issue that Adversely influences the performance and longevity of asphalt overlays over deteriorated pavements. This review Looks for the Technologies which used to reduce the reflection cracks propagation by insert a new Strategies and different design materials. This research dealt with many treatments such as: increasing the layer thickness of Hot Mix Asphalt (HMA), creating modified asphalt by adding polymers to asphalt, rubberizing asphalt, carbon black, sulfur and other different materials. Geosynthetic materials were studied and analyzed to evaluate their ability to increase the layer tensile strength and minimize the effect of reflection cracks such as geotextiles, geogrids, and Stress Absorbing Membrane Interlayers (SAMI). The research shows that the increasing of overlay asphalt layer thickness leads to durability development. On the other hand, using developed materials like Polymer-Modified Asphalt and Stress Absorbing Membrane Interlayers (SAMI) Strategies leads to increasing the service life of the repaired pavement. The conclusion indicated that the development of overlay asphalt layer thickness and layer reinforcement and applying advanced environmental systems can be improving the pavement performance. These Strategies can produce a perfect solution to prevent or reduce the reflection cracks in rigid and flexible pavement.
Specimens with the structure of a face-centered cubic were produced using several sets of printing conditions. An experimental testing is conducted to carefully evaluate the microstructural analysis and compressive strength of this structure. The results include the measurement of mechanical properties, such as the peak stress. Fused deposition modeling is employed for the additive manufacturing of experimental specimens made from shape memory polymer thermoplastic polyurethane (MM-3520). We take into account the impact of printing factors on lattice structures, such as layer thickness, printing temperature, and printing speed. Analyzing the microstructure of the printed specimens exhibits that the specimens with highest printing temperature, lowest printing speed and thinner printing layer have better layers adhesion and lower porosities. All the mechanical tests are performed on specimens with the same structure and at a relatively constant density. Among the tested printing parameters, using a layer height of 0.1 mm, a printing temperature of 230 °C, and a printing speed of 20 mm/s yields the highest strength in the specimens. However, specimens printed with a layer height of 0.2 mm, a printing temperature of 220 °C, and a printing speed of 30 mm/s also exhibit good strength, albeit slightly lower than the maximum values. Additionally, when using these specific settings (0.3 mm – 210 °C – 40 mm/s), the mechanical qualities are minimized, yet the stress-strain curves exhibit characteristics similar to elastomers.
One of the health issues that many people encounter on a daily basis is bone fracture, which can happen for a number of reasons, such as arthritis, sprains, or external trauma . The patient experiences instability as a result of these issues . Internal fixation is a type of surgery used to support and mend a damaged bone Treatment options include ankle joint fixation, a surgical procedure employing pins, plates, rods, or screws. This study uses gait analysis methods to assess lower limb biomechanics . Gait analysis is vital for understanding walking patterns and intervention effectiveness. The impact of different shoe designs on ankle mechanics, using the finite element method and ANSYS, is investigated The results of the EMG and the GRF were discussed._x000D_ This research deepens our understanding of lower limb biomechanics and ankle joint health. By evaluating stress effects and designing custom shoes, it enhances ankle injury treatment and management strategies._x000D_ The patient, a 70-year-old woman with an internal fixation on her ankle joint, underwent a CT scan of her ankle. The patient underwent a number of experiments to evaluate her stability. EMG was used to determine the muscle stress for a brief period of time, and ground reaction force was then used to determine the pressure of walking. Both EMG and GRF have two walking speeds of1.5and 2 km/h while wearing four different types of shoes. The behavior of the EMG demonstrates that the stress on the muscle increases as walking speed increases, and the results varies depending on the shoe. The patient is afraid to apply pressure to the injured foot, so the health foot has better pressure over the entire foot_x000D_
Many joints in the body depend on cartilage for their mechanical function. Since cartilage lacks the ability to self-heal when injured, treatments and replacements for damaged cartilage have been created in recent decades. The mechanical tests had an important role in the treatment and designing of the replaced cartilage. There are two types of cartilages in the knees: fibrocartilage (the meniscus, it is a special type of cartilage) and hyaline cartilage. Its mechanical properties are important because structural failure of cartilage is closely related with joint disorders. This study aimed to determine the stress-strain curve to give broader understanding of the material’s properties. The results of this study could help to develop computational models for evaluating mechanics of knee joint, predicting possible failure locations and disease progression in joints.The study involved two specimens taken from bovine, the first was the articular cartilage with subchondral bone and the second was the meniscus cartilage each one loaded on a compressive testing machine to compute the displacement, and the force applied, enabling the calculation of the stress-strain curve of the material.Specimen failure occurred in the articular cartilage surface at a force break of 73.8N and get force peak about 87.2 N. The meniscus cartilage failure had occurred at a force break of 29.2 N and get force peak about 34.9 N.
Orthoses and prostheses were Chosen and laminated based on their high Yield, ultimate stresses, bending stresses, and fatigue limit. Response Surface Methodology (RSM) was utilized to find the best values for two parameters reinforcement perlon fiber and percent of Titanium Nanoparticle coupled with the matrix resin during optimization. The response surface methodology combined the expertise of mathematicians and statisticians to construct and analyze experimental models. Using this method, we identified 13 different lamination samples comprising a wide range of perlon number and Ti nano Wt% in their Perlon layer composition. All lamination materials defined by RSM methods and produced by a vacuum system were subjected to a battery of tests, with fatigue tests performed on the ideal laminating material in contrast to laminations created in the first study (Tensile test, Bending test, and Fatigue tests according to the ASTM D638 and D790 respectively). In comparison to the other 12 laminations tested using Design Expert version 10.0.2, the lamination with ten perlon layers and 0.75 percent Ti nano proved to be the strongest overall in terms of Yield, ultimate, and bending loads. This study used composite materials and titanium nanoparticles to characterize and fabricate ankle foot orthoses. Strength in bending should amount to about 70 MPa, around 85 MPa in tensile tension. Two empirical quadratic equations for the models of peak bending strength and maximum tensile stress with 95% confidence were created using the response surface approach and analysis of variance within the design of experiments software.
This work involved two major parts: the first one is the experimental part which included treatment of scoliosis deformity by manufacturing thoracolumbosacral orthosis, measuring the cobb angle of deformity, measuring the gait cycle data and walk path for both legs and suggesting a composite material to improve the mechanical properties of the orthosis and finally the interface pressure between trunk and orthosis is measured for twelve points covering of the total TLSO surface area by using f-socket devise. The second part of this study is the numerical simulation part during which the stresses are calculated using Ansys software for calculating stresses due to interface pressure loading boundary condition. The result shows no deference in gait cycle phases but the clear difference noted in walking path due to deviate center of mass, maximum pressure recorded left thoracic region with 900KPa due to correct spinal deformity while the minimum pressure recorded at right chest with l40KPa because of it is tissue region and Maximum value of stress was recorded at the left thoracic region with 2.81MPa due to Maximum interface pressure at this point.
The study here under describes the impact of adding a nano-scaled ceramic particles on the mechanical and fatigue behaviors of aluminum matrix composites AMCs containing 0.5 ,1.0 ,1.5, and 2 % wt. of nano-scaled B4C and Al2O3 particles were dispersed in molten aluminum by the stir-casting process. Vickers, tensile, and fatigue devices were utilized to evaluate the mechanical behavior of composites in the fabrication process. The results show that increasing the weight percentage of nano-ceramic particles increased the hardness, maximum tensile stress, and fatigue strengths of the base alloy. Furthermore, all of the above behaviors of AMCs reinforced with B4C particles are better than those of AMCs reinforced with Al2O3 particles.
Pressure vessels are the heart of plants and oil refineries stations. In many engineering applications such vessels can be subjected to periodic loading either internally due to the charging and discharging process or externally due to the excitation from other nearby components such as pumps, compressors or from seismic. So that in spite of a good design according static assumption it may be critical in dynamics. In this work a horizontal pressure vessel with accessories subjected to liquefied petroleum gas pressure LPG is considered. Three models of different head types are investigated herein namely; Deep torispherical, Elliptical 2:1 and Hemispherical. The design and material selections are chosen as per ASME. For practical service many accessories are attached to the vessel such as manhole, supports, inlet and outlet opining. Finite Element method via ANSYS R18.2 is introduced for the numerical analysis. The fatigue life in case of fully reversed cyclic loading are estimated and located. Vibration characteristics such as mode shapes and natural frequencies for the lowest five modes are evaluated and compared. It is found that the fatigue life can be increased as higher as 180% for hemi- spherical head as compared with deep torispherical head pressure vessel and the lowest four natural frequencies are nearly identical for all models, however significant change observed in the fifth natural frequency.
Prosthetic is an artificial tool that replaces part of the human frame absent because of ailment, damage, or distortion. The current activities in Iraq draw interest to the upper limb discipline because of the growth in variety of amputees and. It is necessary to do extensive researches in this subject to help lessen the struggling of patients. This paper describes the design and development of low-cost prosthesis for people with transradial amputations. The presented design involves a hand with five fingers moving by means of a gear box mechanism. The design of this artificial hand allows five degrees of freedom(5DOF), one degree of freedom for each finger. The artificial hand works by an actuation system (6V) Polou motor with gear ratio equal to 50:1 due to its compactness and cheapness. The designed hand was manufactured by a 3D printing process using polylacticacid material (PLA). Some experimental were accomplished using the designed hand for gripping objects. Initially the EMG signal was recorded when the muscle contracted in one second, two seconds, three seconds. The synthetic hand was able to produce range of gesture and grasping moves separately just like the actual hand by using KNN classification which are complete hand Pinch, fist, and jack chuck. The simulation of the fingers movements was achieved using ANSYS software to analysis the movement (pinch, fist, and jack chuck), obtain bested of stress influencer at each finger, and maximum deformation at each movement.
The process of placing the brackets in their proper positions in the field of orthodontics is consider one of the main steps in orthodontic treatment. In order to achieve high accuracy placements for the brackets, many methods are available today, starting from direct and indirect methods, each of them has advantages and disadvantages regarding the accuracy and the time for patient treatment. In this study, a new mechanism is introduce with its mechanical behavior in order to reduce the time required for patient treatment and to increase the accuracy for bracket placements. The newly mechanism was designed using Solidworks CAD software with a total Virtual functionality for all of the parts of the assembly, then a simulation was carried out to find the stress distribution, deformation, and strain on the main parts of the proposed assembly. The finished design shows a high precision mechanism that is able to place brackets one by one on the teeth.
This study implements the soft computing techniques such as Artificial Neural Network (ANN) and an adaptive Neuro-Fuzzy (ANFIS) approach. Thus to model the rutting prediction with the aid of experimental uniaxial creep test results for asphalt mixtures. Marshall samples, having Maximum Nominal Size of 12.5 mm, have been selected from previous studies. These samples have been prepared and tested under different conditions. They were also subjected to different loading stress (0.034, 0.069, 0.103) MPa, and tested at various temperature (10, 20, 40, and 55) °C. The modeling analysis revealed that both approaches are powerful tools for modeling creep behavior of pavement mixture in terms of Root Mean Square Error and Correlation Coefficient. The best results are obtained with the ANFIS model.
Friction Stir Welding is one of the most practical welding process at the solid state. Friction Stir Processing is used to enhance the microstructure of FSW welded zone. The present study investigates the effect of welding parameters on the tensile properties of FSW and FSP joining 3 mm AA 5083 - H111 aluminum alloy by means of stress – strain curve with a uniaxial tensile test and by comparing the efficiency between FSW , FSP and base metal .The experiments were conducted with 1000,1500 and 2000 rpm rotation speeds ,and 20,40 and 60 mm/min travel speed. The best result of the welding joint was shown at the 20 mm/min feed speed and 1500 rpm rotational speed for FSW, and 40 mm/min feed speed and 1500 rpm rotation speed for FSP. The efficiency of ultimate tensile strength reaches to 92% for FSW and 94% for FSP.
The effects of the ultrasonic peening treatment (UPT) on the rotating bending fatigue behavior and the behavior of the vibrations of alloy steel DIN 41Cr4 were studied. Hardness test, Tensile test, Constant amplitude fatigue tests, and the vibrations measurements have been carried out on the specimens. Also, the fracture surface was examined and analyzed by a Scanning Electron Microscope (SEM). The results of the investigations, e.g. stress to number of cycles to failure (S-N) curves, fatigue strength improvement factor was 7%. The decreasing percentage of maximum Fast Fourier Transform (FFT) acceleration of the ultrasonic peened condition compared to the untreated conditions was 45%.
Kids carrying heavy loads as a part of everyday activity may be related to bend their trunks forward to maintain body posture and balance while walking. This study was to determine a correlation between the weight of a child's backpack, their body weight, and certain features of their body posture. The study group consisted of 6 children, in age of primary school. The anthropometry (age, length, weight) were taken for each volunteers. A school backpack was specially built for the present study. Walking gait was filmed in three cases: (zero kg, 3 kg and 6 kg) backpack.Posture was analyzed by using (Kenova and MATLAB) computer programs.The results show that the forward inclination of the trunk increases when the load and the walking distance are increased, this forward inclination segment may impose greater stress over the vertebral column (ligaments and intervertebral disks) and increase the risk of back problems.Spine and back health may be adversely affected by load carriage and it may be important to use spinal curvature as a measure of posture for load carriage. This study shows that the backpack load cause a lumbar asymmetry by 10 to 20 degree according to the load which has a significant amount of back pain in kids.
In this work chopped carbon fibers are used to improve tensile strength of Porcelanite lightweight aggregate concrete. Silica fume was added in order to improve the mixes compressive strength. Silica fume increase water demand and using fibers reduce workability, to improve workability and decrease water demand high rang super plasticizers are used. The results showed that compressive strength, splitting tensile strength, modulus of elasticity of carbon fibers Porcelanite lightweight aggregate concrete increase with increasing of carbon fiber up to 2% compared to reference Porcelanite lightweight aggregate concrete without fibers. The percentages of increasing were 14.40%, 68.00%, and 10.66% for compressive strength, splitting tensile strength, and modulus of elasticity, respectively. Flexural Strength continues in increase with increase of fibers. The dry unite weight of mixes with chopped fiber decrease with increase of fiber percentage. Besides the chopped carbon improved the ductility of Porcelanite lightweight aggregate concrete and that clear from stress-strain relationship.
The finite element method is one of the important methods in analyzing geotechnical engineering problems; its main advantage is the ability to apply for the materials exhibiting non-linear stress-strain behavior. In this study the finite element program PLAXIS 3D 2013 is used to study the behavior of the piles under the influence of seismic waves in saturated sandy soil and the effect of adding geogrid with the pile foundation. The program has been used to facilitate the representation of the real model, input the required soil parameters and implementation of seismic data. Seismic wave, the soil geometry and the pile dimensions were fixed in all models, while dimension and depth of the geogrid used were varied to study the influence of different depth and dimension in reducing the pile displacements and the pore water pressure of soil. The results show that The reduction in settlement ratio (the difference between settlement of pile without and with using geogrid to the settlement without using geogrid) for ( ×L/2), (L×L) and (2L×2L) are 10.6%, 17% and 21.3% respectively. And the settlement ratio for geogrid at depths 8.33% and 12.5% of pile length are 9.6% and 17% respectively.
Three decades of empirical research have proven that well-being in humans is stimulated by designs that link people to natural elements and landscapes. Environmental psychology research also revealed that these characteristics can lower stress and anxiety while having a positive impact on human productivity. therefore, there were more recent interest from theorists and architects to discover approaches to re-connect the constructed environment with the natural components. One of the most current theories of re-communication and its use in architecture is called "biophilia.". Therefore, the research problem is the lack of knowledge of biophilic architecture and what are the most prominent features affecting the user. the research aims to shed light on the basics of this design theory as well as testing its design patters in the educational environment to find out which attributes are most effective for users in improving productivity and well-being By adopting the quantitative descriptive approach and based on a questionnaire for the purpose of adopting it in design and to aid in the practical application of the Biophilia idea by designers and architects. The research concluded that there are design features that are more important than others for educational buildings, such as (day light, water, air, plants, landscapes, mobility, integrating the parts to create the whole).
The present work deals with direct diffusion bonding welding without interlayer of austenitic stainless steel type AISI 304L with Oxygen Free High Conductivity pure copper (OFHC) in vacuum atmosphere (1.5 *10-5 mbr.). The optimum bonding conditions are temperature of 650 ?C, duration time of 45 min. and the applied stress of 30 MPa, in order to secure a tight contact between the mating surfaces. The corrosion behavior of diffusion bonding joints in 3.5% Nacl is studied to evaluate the corrosion resistance of welding joints by using Potentiodynamic method. The observed microstructure of corroded specimen of optimum diffusion bonding joint shows that the corrosion current density has low value as compared with base materials used. During polarization, galvanic coupling is observed between two materials used. At passivity region, inverse polarity is occurred at 450mV. Therefore, passive stainless steel 304 L behaves as cathode respective to pure copper, the corrosion behavior of the diffusion bonding joint was mostly by copper side. The corrosion results indicate the presence of galvanic effect. The corrosion current density of copper, stainless steel 304L and bond joints condition were (3.66 µA/cm2, 1.62 µA/cm2 and 1.85µA/cm2) respectively. A SEM examination of corroded diffusion bonding joint indicates that the galvanic corrosion happened on copper side. The corrosion rate of bonding joint conditions was 0.85 mpy, which is less than 1%. This means that corrosion resistance of bond joint is more than excellent.
The effect of fines content (material finer than 0.075 mm) on the mechanical properties of subbase course aggregate is studied in this paper. a laboratory tests were carried out using percentage of fines material 5%, 10% and 15% by weight adding to the original subbase aggregate class B according to Iraqi specification (SCRB) which the specification limit the range of fines between 5-15%. The repeated load CBR test was done to study the mechanical properties; accumulative permanent, elastic deformation and equivalent elastic modulus.The RL CBR test was useful technique to assess the influence of fines material and stress level on the equivalent elastic modulus, and on the evolution of deformation. The equivalent modulus increase when adding 5% of fines material in case of plastic fines, but in case of non-plastic the increase continues until adding 10% fines material. Adding fines material also led to change in accumulative permanent deformation, where adding 5% fines material increase the permanent deformation by 36%, 5% for material with plastic fines and 20% for material with non-plastic fines for unsoaked samples. In case of soaked samples permanent deformation increase by 28% and 25% at adding fines material for material with plastic fines where decrease by 1% at adding 5% fines to original granular material with non-plastic fines. The theoretical modeling show that the deformation increase by increasing number of loads repetitions.
The traditional electric poles in Iraq are usually made from steel materials. Such materials induced high weight, corrosion, permanent deformation caused by high wind speed, etc. The study aimed to numerically examine the strength of few poles made from different materials. The pole subjected to pressure developed by actual measured wind speed of 140 km/h. The numerical model of different materials and cross sections, an octagonal section electric pole made from composite material FRP–HDPE–FRP is suggested to replace the traditional one. The results showed high safety factor, approximately 5.51 besides the low ratio of high strength to weight as compared to steel materials. Using HDPE as reinforced material resulted in pole elastically deformed with only 0.222 mm. Therefore, it can be assumed that the suggested pole acts partially as a damper. Straight octagonal cross - section of pole promoted high reduction (74.22%) in maximum Von–Misses stress of that obtained in cylindrical three-stage pole. High reduction (5.87 times) in maximum deformation value was obtained when composite octagonal pole was used as compare to tapered pole made from steel.
The present investigation looked at whether the Bailey approach to aggregate gradation could be used to construct Superpave HMA blends. It also looked at how this approach influenced the rutting performance associated with these mixes and compared it to mixes of asphalt created by Superpave gradations. The current research included four aggregate gradations: both fine and coarse gradations for the Superpave and Bailey gradation procedures. The repeated loading test was utilized to assess the rutting performance. The findings indicated that temperature, stress level, and aggregate gradation all had a significant impact on rutting performance. In contrast to the other three gradations, the third mixture gradation exhibited the least amount of non-reversible deformation. It translates to pavement that is more resistant to rutting and less susceptible to it.
Recently, considering polymer composite in manufacturing of mechanical parts can be caused a fatigue failure due to the very long time of exposure to cyclic loading and may at environmental temperatures higher than their glass transition temperature; therefore, in this paper, a comprehensive investigation for bending fatigue behavior at room and elevated temperatures equal to 60 °C, 70°C, and 80 °C will be done. Rotating bending test machine was manufactured for this purpose supplied with a connected furnace to perform fatigue tests at elevated temperatures. The obtained results appeared that the increase in applied stress and temperature caused a clear reduction in fatigue life; also the addition of carbon nanotubes enhanced the fatigue life at different temperatures by 183%, 205%, 218%, and 240%, respectively while the addition of short carbon fibers improved fatigue life by 324%, 351%, 387%, and 415%, respectively. As well as, Polyamide 6,6/carbon fiber composite appeared fatigue limit at temperatures equal to 20°C and 60°C and stresses approximately equal to 55 MPa and 38 MPa respectively.