In this study an attempt is made to derive governing equations satisfying equilibrium and compatibility, for multi-layer composite simply supported beam under blast loading , for linear material and shear connector behavior in which the slip (horizontal displacement) and uplift force (vertical displacement) are taken into consideration. The analysis is based on an approach presented by Roberts, which takes into consideration horizontal and vertical displacements in interfaces. The model consists of a simply supported beam with three layers having a cross-sectional area ,different dimensions and material properties. The analysis led to a set of six differential equations containing derivatives of the fourth and third order. The blast loading was considered as a function of time. Explosions have different effects including blast, penetrations and fragmentation. The blast is the main effect which hits the structure in short duration. Multi –layer composite construction is the best type of constructions to resist the blast loading ; according to this , multi-layer composite construction is used for air-craft and marine industries. Analysis of composite beam under blast load , taking in consideration vertical and horizontal displacements, leads to six differential equations , the load is taken as a function of time.
In this study an attempt is made to develop a method of analysis dealing with a multi-layer composite continuous beam , for linear material and shear connector behavior in which the slip (horizontal displacement) and uplift force (vertical displacement) are taken into consideration. The cross-sectional area for the beam consists of three layers varying in thickness and shear stiffness. The analysis is based on a approach presented by Roberts[1], basically for two layer simply supported beam, under uniform and point loads , which takes into consideration horizontal and vertical displacement in interfaces. The analysis led to a set of eight differential equations containing derivatives of the fourth and third order. A program based on the present analysis is built using finite difference method using boundary conditions. A comparison between the present analytical solution and previous studies shows close agreement. Continuous composite beams are very important element in construction of high rise buildings , multi-story frames and bridges, due to great advantages that can be obtained by using this sort of structural elements, such as reducing the beam moments, suitable reduction in deflections. The model deals with continuous beam consisting from three layers as a cross-sectional area with inter-layer slip. The cross-sectional area consist of composite material including intermediate layer from concrete and an upper and lower material with high strength in tension and compression ( i.e. steel plates or steel beams )
The convergence of cloud and edge computing in smart manufacturing offers significant potential for improving efficiency in Industry 4.0. However, task scheduling in this context remains a complex, multi-objective challenge. This study introduces a novel Cloud-Edge Smart Manufacturing Architecture (CESMA), leveraging a hybrid approach that integrates NSGA-II and the Improved Monarch Butterfly Optimization (IMBO) algorithms. The combination utilizes NSGA-II's global search and non-dominated solution capabilities with IMBO's fine-tuning and local optimization strengths to enhance task scheduling performance. Where CESMA combines the scalability and analytics power of cloud computing with edge-based real-time decision-making to address the dynamic demands of smart manufacturing. Through extensive simulations and experiments, the feasibility and effectiveness of CESMA are validated, showing improved task scheduling quality, resource utilization, and adaptability to changing conditions. This research establishes a robust platform for managing the complexities of task scheduling in cloud-edge environments, advancing intelligent manufacturing processes, and contributing to the integration of evolutionary algorithms for real-time industrial decision-making
Responding quickly and economically to the diversification of customer needs has forced manufacturing companies adopting approaches to delivering low cost, high quality sustainable products based on finding a link between the design or the manufacturing processes and other key elements of sustainability; economic, environmental, and social. However, these approaches had limited success. The most likely reason for the lack of integration between the design and manufacturing stages of the product and complexity of addressing the above mentioned three key elements of sustainability due to existing of many variables in relation to design, manufacturing, locations, logistic operations and so on. Taking into account the required integration as well as the associated complexity of considering sustainability elements can lead to large space alternative solutions and it is more difficult to use only exact methods to the optimization of such problem. This paper presents a genetic algorithm (GA) approach aiming to optimize a high sustainability performance by designing a product and the corresponding manufacturing processes for that product. Process optimization is carried out in terms of the highest fitness function achieved where different objectives are to be optimized simultaneously. The proposed GA approach is applied to the industrial case example. The proposed approach can assist decision makers to help explain when justifying their decision on what are the best product design and its manufacturing processes to obtain high sustainability performance.
WMAN (wireless metropolitan area network) technology is based on the IEEE 802.16 air interface standard suite, which provides the wireless technology for fixed and nomadic data access. WMAN employs orthogonal frequency division multiplexing (OFDM), and supports adaptive modulation and coding depending on the channel conditions. The objective of this paper is to study the performance of the IEEE 802.16d WMAN physical layer under Nakagami model as a Multi-path and frequency-selective fading channel beside the additive white Gaussian noise (AWGN) and Doppler. Finally, we compared it with the Rayleigh fading model. The transmission bit rate, Probability of Error ( ) and estimated SNR have been compared under single/multi path propagation conditions.
This research presents a mathematical model of feed-interval scallop height, where in a machined surface there are two types of scallop height, the pick(path)-interval scallop and the feed-interval scallop. The pick-interval scallop is generated by the finite pick offset between the successive cutting paths, while the feed-interval scallop is generated by the finite increment between the successive tooth feeds. New model that describes and predicts the geometric generating mechanisms of the feed-interval scallop height have been derived using torus cutter which is commonly used in multi-axis milling machine. The machining parameters (effective tool cutter radius, feed per tooth and the magnitude of tool axis inclination angles) have been considered in theoretical and experimental work to study the effect of these parameters on this type of scallop height. From theoretical and experimental work it was found that at high-speed machining, the feed-interval scallop is more important to the surface roughness than the path-interval scallop, and the feed-interval scallop is very sensitive to the tool-axis inclination angle. The feed-interval scallop height decreased sharply and quickly within a few degrees of the tool-axis inclination to the normal workpiece surface. In general, an inclination angle equal to is good enough for all tool diameters used in the present work, namely (6,8,10 12 mm).
In this research a simply supported beam is used as a master structure with unknown number of attachments (fuzzy substructure) which is modeled as a system of 1-DOF attachments. Two types of attachments models were studied, namely 1-DOF mass attachment model and 1-DOF mass-spring attachment model. It is shown that the effect of attachments on the master structure natural frequencies when modeled as (mass-spring substructure) is larger than that when modeled as (mass substructure) for the same attachment mass. Engineering Statistics and normal distribution were used to find the values of the attachments to be added to the simply supported beam to improve the dynamical properties of the master structure and to find the best distribution of the attachment. The results also show that the distribution of the additional substructure can produce a great change in the natural frequencies so that the proposed statistical approach can be used to find the best distribution of attachments and number, value and location of the additional substructure .
The behaviour of multiple cracked cantilever composite beams is studied when subjected to moving periodic force. In this investigation a new model of multiple cracked composite beams under periodic moving load is solved. Three cracks are considered at different position of the beam for numerical solution. The results from experimental work compared to numerical solution. The multiple cracks are identified easily from the deflection graphs at different force speed. Influences of crack depth at different load speed are investigated
Free vibration analysis of a cracked cantilever beam with two types of additional substructure attachment is investigated using ANSYS program. The cantilever beam is used as a master structure with single substructure attachment in various locations (as 1-DOF mass attachment and 1-DOF mass-spring attachment) with influence of crack in different location and depths. The results for the changes of the natural frequencies of a cracked beam are compared with the results produced by Vahit et al [1]. So the same geometrical properties have been studied. In additional work a cracked beam carrying two types of substructure attachment are compared with the results of the beam without a crack and with multi crack depth. In all calculations the beam has a uniform cross-section and the crack was modeled by reduction in the modulus of the beam. The reducing effects of the cracked beam on the natural frequencies had been more apparent with the substructure attached to the beam in different situations. The effect of mass-spring substructure is larger than the effect of the attachment when modeled as mass substructure for the same mass, with 17% for the first natural frequency and 2% for the second and third natural frequencies. The results can be used to identify cracks in simple beam structure; cracks have a clearer decreasing impact on the natural frequencies.
The Cooper-Harper rating of aircraft handling qualities has been adopted as a standard for measuring the performance of aircraft. In the present work, the tail plane design for satisfying longitudinal handling qualities has been investigated with different tail design for two flight conditions based on the Shomber and Gertsen method. Tail plane design is considered as the tail/wing area ratio. Parameters most affecting on the aircraft stability derivative is the tail/wing area ratio. The longitudinal handling qualities criteria were introduced in the mathematical contributions of stability derivative. This design technique has been applied to the Paris Jet; MS 760 Morane-Sualnier aircraft. The results show that when the tail/wing area ratio increases the aircraft stability derivative increases, the damping ratio and the natural frequency increases and the aircraft stability is improved. Three regions of flight conditions had been presented which are satisfactory, acceptable and unacceptable. The optimum tail/wing area ratio satisfying the longitudinal handling qualities and stability is (0.025KeywordsLongitudinal Handling---Stability---Tail Design
In a Mobile Ad hoc Network (MANET), routing protocols rely on asymmetric links so the received information for one connection is not useful at all for the other one. In this paper there are two approaches put under considerations; the first approach is a simulation of MANET with many nodes in one network based FTP traffic. The second approach is a simulation of the combination between WiFi and WiMax wireless technologies in one network based on the IEEE 802.11 and IEEE 802.16 standards respectively. For these two approaches, the simulation considers the situation that the MANET receives traffic from another network via a common gateway. In addition, the mobile nodes are randomly placed in the network that will provide the possibility of multihop routes from a node to another. The standard MANET’s routing protocol is Ad hoc On-demand Distance Vector routing (AODV), whose performance is evaluated in this work with respect to routing overhead, throughput and end-to-end delay. Several scenarios' simulations using WLAN technology were tested to investigate the behavior of the network performance for logical and office applications with fixed and mobile workstations. These networks are considered to operate on a single-hop or multi-hop basis where nodes in the network are able to act as intermediaries (routers) for communications of other nodes. Nodes in these networks are forced to operate with power limited batteries for power saving goal as well as the bandwidth constrained is considered.
The Cross-Rolling (CR) process is a severe plastic deformation technique that was used to roll aluminum alloy 6061. However, this process is accompanied by many disadvantages, such as spring back due to elastic recovery. This research aims to investigate the effect of cross-rolling on the spring back phenomenon by examining the main parameters that affect the forming process. Two different routes of cross-rolling were used: the first route, called two-step cross-rolling (TSCR), and the second, multi-step cross-rolling (MSCR), were employed to achieve high deformation and superior mechanical properties. The samples were bent using the V-bending process at three different speeds (5, 10, and 15 mm/min). The results showed that the rolling route and the change in cutting direction led to increased plastic deformation, thus increasing the spring-back factor. The type of route and cutting direction significantly impacted both the maximum load and the springback results.
Materials selection is a multi-criteria decision-making (MCDM) problems because the large numberof factors affecting on decision making. The best choice of available material is critical to thecompetitiveness and success of the manufacturing organisation. The analytical hierarchy process(AHP) is an important tool to solve MCDM problems. The choosing process of suitable material(such as a refrigerant fluid) for the Air Condition System (ACS) is faced with challenges such aslack of a systematic approach in setting the optimal performance in terms of its impact on theenvironment and operation. Selecting process for the one refrigerant from a range suitable ofsuitable refrigerant is complex process. The study presents a comparative performance analysisof ACS for using four alternative refrigerants R290, R410, R404 and R22. Then, one of these suitablerefrigerant is selected. The comparison is based on three criteria system operation, environmentand maintenance.Novels ACS performance assessment model is proposed based on an analytical hierarchy process(AHP). The model is based on two main criteria of ACS, quantitative criteria, cooling capacity(CC), coefficient of performance (COP), etc.).And qualitative criteria (Ozone Depletion Potential (ODP), Global Warming Potential (GWP) andmaintenance cost (MC)). It is necessary to look for new technique help decision making to selectalternative refrigerants, to fulfill the goals of the international protocols (Montreal and Kyoto)and optimum operation, to satisfy the growing worldwide demand, in addition the increase outdoortemperature in some countries.This study provides a developed methodology for evaluating ACS performance. Moreover, it helpsto select a robust decision. The results obtained from AHP process that the best rank of the suitablerefrigerant was R404 (0.3763) followed by R22 (0.3657) and so on for the other. Therefore,the proposed methodology can help the decision maker to select the best alternative for bothcriteria (qualitative and quantitative) in complex selecting process.