In this study, the Transient dynamic analysis of grid-stiffened composite conical shells is discussed. The Transient dynamic response of the composite conical shell with simply supported boundary conditions under the lateral impact load, which is applied extensively and uniformly on a certain surface, is obtained using the convolution integral and based on the method of addition of modes. The validation of the obtained results has been done with the help of references and ABAQUS finite element software. The effects of various parameters such as fiber angle, geometric ratios, type, etc. have been investigated in forced vibrations. Finally, the effect of reinforcing the conical shell with the help of grid-stiffened structures has been studied.

A novel semi analytical method is developed for Transient analysis of single-lap adhesive joints with laminated composite adherends subjected to dynamical loads. The presented approach has the capability of choosing arbitrary loadings and boundary conditions. In this model, adherends are assumed to be orthotropic plates that pursuant to the classical lamination theory. Stacking sequences can be either symmetric or asymmetric. The adhesive layer is homogenous and isotropic material and modelled as continuously distributed normal and shear springs. By applying constitutive, kinematics, and equations of motions, sets of governing differential equations for each inside and outside of overlap zones are acquired. By solving these equations, the time dependent shear and peel stresses in adhesive layer as well as deflections, stress resultants, and moment resultants in the adherends are computed. The developed results are successfully compared with the experimental research presented in available literates. It is observed that the time variations of adhesive peel and shear stress diagrams are asymmetric for the case of symmetric applied load with high variation rate. Moreover, it is reported that although the magnitude of applied transverse shear force is reduced to 10% of applied axial force, however a significant increase of 40% in the maximum peel stress attained.

In this paper for handling improvement and lateral stability increment of a four-wheeled vehicle a new robust active control system is proposed. First, to establish an accurate model of the vehicle, a fourteen-degrees-of-freedom nonlinear dynamic model is developed. model of the vehicle, a fourteen-degrees-of-freedom nonlinear dynamic model is developed. Then, the nonlinear dynamic model is validated using CarSim software in a standard maneuver. Next, a new active steering control system was designed based on a simplified two-degrees-of-freedom dynamic mode to control the lateral motion of the vehicle. Two state variables, namely the vehicle’ s yaw rate and the vehicle’ s lateral velocity, are controlled using the control system. Also, the sliding mode control method is used to eliminate the error between the actual response and the desired response. Moreover, a complete stability analysis is presented based on the Lyapunov theory to guarantee closed-loop stability. Simulation results show that the controller is able to increase the vehicle’ s maneuverability, especially during severe double lane change maneuver in which intense instability occurs. More investigations demonstrate that the proposed control system can considerably improve the vehicle’ s path tracking under uncertainties.

dynamic compaction in urban areas has great potential to damage nearby structures and their occupants due to induced vibrations. One common approach to keeping these vibrations in a safe range is installing a barrier crossing the wavefronts. Previous studies have largely focused on evaluating the effectiveness of trench barriers in reducing continuous vibrations, while the efficiency of boreholes as an alternative approach with a lower volume of excavation has not been thoroughly investigated. This study uses ABAQUS software to compare the efficiency of borehole and trench barriers in reducing vibrations induced by the dynamic compaction (DC) process using a 3D model validated by in-field study results. The study uses a row of hollow boreholes with varying diameters, depths, and center-to-center distances located at a fixed location from the tamping point to investigate the efficiency of borehole barriers based on their geometrical parameters. Open trenches with varying lengths, depths, and distances from the tamping point are also used for comparative investigations. The results indicate that the trenches have overall better performance than borehole barriers, However, properly designed boreholes can still reduce vibrations to an acceptable extent. Finally, the study presents design guidelines for further practical applications.

Due to the lack of measurements in many regions, wave characteristics are estimated using different methods. Wave climate hindcasting/forecasting is mostly conducted by numerical models or empirical methods. Until now, different empirical methods have been developed for wave hindcasting. However, with the development of high speed processors, several sophisticated numerical models have been developed for wave prediction. These models are mostly phase-averaged spectral wave models developed in three generations. In the last two decades, third generation wave models have been used widely in academic and practical projects. In this regard, Port and Maritime Organization has produced his own model, PMO dynamic. This model has been developed as a part of first three phases of Monitoring and Modeling of Study of Iranian Coasts project. PMO dynamic package is a software available for engineering purposes. It has several modules that have been developed for different objectives. Wave model is the module which is used for the generation and transformation of wind waves in coastal areas. In this paper, in order to test the PMO dynamic model capabilities, it has been applied for the prediction of wave parameters in Bushehr Bay and the results have been compared with MIKE21 SW model and measured data.

In this study, dynamic response of an articulated vehicle carrying liquid in a circular cylindrical tank at steady state and Transient maneuvers has been investigated. A sixteen degree-of-freedom nonlinear dynamic model of an articulated vehicle was initially developed, then it was validated using TRUCKSIM software for standard maneuver. dynamic interaction between the vehicle and the liquid is studied using potential function method. In potential function method, the liquid free surface gradient subjected to roll angle and lateral acceleration of the semi-trailer can be determined with assumptions of non-viscous fluid flow and calculation the pressure gradient. The simulation results show the interaction between the vehicle dynamic and liquid. Further research shows that roll stability of the articulated vehicle carrying liquid is intensely affected by sloshing of the liquid and lower rollover stability limit is observed for this vehicle than the same vehicle carrying rigid cargo, especially under lane change maneuver.

This article examines the simulation, optimization and dynamic modeling of a multi-source energy production system. This system includes solar panels and CCHP devices as the main energy production equipment and the target functions also include: total electricity consumption, total gas consumption, CCHP fuel consumption as well as return on investment, as the economic and energy response of the system. Further analysis of the dynamic results of the system includes: temperature changes, efficiency and average daily electricity produced by solar panels, average daily absorbed energy in solar collectors, hourly changes in electricity demand, electricity produced by solar panels and electricity produced by CCHP, the hourly changes in electricity demand, the total electricity produced and the hourly changes in gas consumption demand of the system and the complex will be investigated throughout the year. The results show that the utility distribution in the optimization section is 0. 735. This number showes that the system is in a suitable and ideal state and the return on investment can be justified with 1. 64 years. Also, even though the amount of solar radiation is higher in the hot months of the year, but due to the increase in the temperature of the solar cell, the efficiency of the solar panel decreases. These systems are also able to use solar energy to provide part of the heating needs of the complex’s hot water system. The design and use of the combined optimal system of CCHP and solar panels allow the complex to fully and sustainably supply its electricity needs provide and even sell the excess amount of electricity to the public power grid and use it as a source of additional income.

Background: In intertrochanteric fractures، dynamic hip screw (DHS) is the most frequently used tool، but several studies did not give good results for this device in reverse-oblique and transverse fractures. Current study aimed to compare fixation results of reverse-oblique intertrochanteric and short-segment subtrochanteric fractures using dynamic condylar screw (DCS) and DHS in patients referred to Alzahra and Kashani Hospitals in Isfahan, Iran.Methods: In a cross-sectional study، medical files of the patients referred to emergency units of the two hospitals who were diagnosed with intertrochanteric or subtrochanteric fractures and underwent DHS or DCS surgery more than 6 months before were assessed; they were invited for follow-up visit and examination. Written consent forms were taken from all the patients upon their entry; and they were examined in terms of complications including nonunion and failure of device and level of fracture improvement. These cases were evaluated by simple radiography ,too. Results obtained from examination of patients in addition to demographic information were recorded in the data collection form for each patient.Findings: Perfect union was observed in 14 (of 25) patients in DHS group and 21 (of 25) patients in DCS group (56% vs. 84%) six months after the surgery. Bone union was significantly better in DCS group (P=0.031). In addition, six months after the surgery, the devices used in 14 people in DHS group and 24 people in DCS group were fixed and the difference between the two groups was significant (P=0.001). 14 and 24 patients had total recovery in DHS and DCS groups، respectively (20% vs. 44%) with a significant difference (P=0.020).Conclusion: Considering obtained results, it can be concluded that using DCS is recommended over DHS due to severity of pain, bone union and fixation of the device.

Demand increase for reduction of fuel consumption and emissions of internal combustion engines has caused technology development in the automobile industry. A successful solution is downsizing the internal combustion engines and adding turbochargers to them. One of the consequences of adding turbocharger to the engine is slower Transient response of the engine in comparison to the naturally aspirated engines. In this paper, the engine simulation is done in one-dimensional software GT-POWER and the torque Transient response is being focused. For optimization, the coupling between two software of GT-POWER and MATLAB SIMULINK is used to find a rapid way for calculation of a proper strategy in order to utilize variable valve timing (VVT) technology during the Transient. Variable valve timing in this study refers to opening and closing timing of inlet and exhaust valves. The optimization target is to maximize the torque integral during time interval of the Transient. The Transient in this paper is the one in which the engine speed is constant and the load increases rapidly and suddenly to a special value (step increase of load). Improved genetic algorithm is used for optimization. The studied engine is 1. 65 liters EF7-TC which is a spark ignition engine equipped with turbocharger.

Plastic pipes are widely used in pressurized water systems. The analysis of Transient flow and estimation of maximum and minimum pressure wave propagation in pipeline and pipe networks is required for design and practice of piping systems, pumping stations, and dam water conveyance tunnels. The viscoelastic properties of the polyethylene pipes have significant effect on the estimation of pressure wave speed and attenuation in Transient flow. The use of polymeric pipes such as polyethylene and polyvinyl chloride has recently increased due to their technical and economic advantages over steel and concrete pipes. Due to viscoelastic behavior, polymeric pipes have a significant impact on Transient flows (Pezzinga, 2002). In a fast Transient flow event like water hammer, viscoelastic properties of polymeric materials cause a residual stress in the pipe wall. These deformations will not return to their original state immediately after unloading (Covas, 2003). This viscoelastic behavior also affects the intensity, shape, and dampening of pressure oscillation in Transient flows. Covas (2003) developed a numerical model to simulate the viscoelastic behavior of the pipe wall in Transient flow events. In this study, the results of a linear viscoelastic model were compared with experimental results in the presence and absence of unsteady friction loss. Soares et al., (2008) also considered Transient flow in PVC pipes, and their results were in good agreement with those obtained by Ramos et al. (2004). Evangelista et al., (2015) studied water hammer phenomenon in a Y-shaped system both experimentally and numerically. According to their results, the linear viscoelastic model was able to simulate the water hammer phenomenon in this system...