Dynamic analysis of swivel construction method under multi-variable coupling effects

2019 ◽  
Vol 10 (4) ◽  
pp. 580-598
Author(s):  
Wang Jiawei ◽  
Sun Quansheng
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Static Analysis ◽  
Friction Stress ◽  
Construction Method ◽  
Coupling Effects ◽  
Content Type ◽  
Multiple Factors ◽  
Real State ◽  
Variable Coupling

Purpose Swivel construction is a new bridge construction method, which can minimize the impact on railway and highway traffic. Previous studies were based on single factor and static analysis, which cannot reflect the real state of structures. The purpose of this paper is to establish a dynamic model of the structure and to analyze the situation under multi-variable coupling effects to accurately simulate the real state of the structure. Design/methodology/approach Finite element software ANSYS was used to establish dynamic model of turntable structure and then to analyze the effects of multiple factors on total stress, friction stress and slipping distance of the turntable structure. Findings It is concluded that the unbalanced weight and radius of spherical hinges have great influence on the turntable structure, so the design should be strictly considered. Friction stress and angular acceleration have little effect on the turntable structure. Originality/value This paper provides simulation of the whole process of swivel construction method. Whereas previous studies focused on static analysis, this paper focuses on the dynamic analysis of swivel construction method. The mechanics of the swivel structure under multiple factors was analyzed. According to the analysis results, the design parameters of the turntable structure are optimized.

Fatigue assessment based on hot-spot stresses obtained from the global dynamic analysis and local static sub-model

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Cristiane Oliveira Viana ◽  
Hermes Carvalho ◽  
José Correia ◽  
Pedro Aires Montenegro ◽  
Raphael Pedrosa Heleno ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Modal Analysis ◽  
Static Analysis ◽  
Structural Model ◽  
Hot Spot ◽  
Superposition Method ◽  
Hot Spot Stress ◽  
Content Type ◽  
Global Dynamic ◽  
Critical Detail

Purpose The purpose of this paper is to evaluate the fatigue process through the dynamic analysis of the global structural model and local static sub-modelling in a critical detail using the hot-spot stress approach. The detail was studied in three different positions at the “Alcácer do Sal” access viaduct, and the methodologies from the IIW and Eurocode EN 1993-1-9 were compared. Design/methodology/approach In this study, the fatigue life process based on the hot-spot stress approach was evaluated using a global dynamic analysis and a local sub-modelling based on a static analysis of welded connections in the “Alcácer do Sal” railway structure, Portugal, taking into consideration the recommendations from IIW and Eurocode EN 1993-1-9. The hot-spot stresses were calculated through the static analysis of the sub-model of the welded connection for each vibration mode with the aim to obtain the temporal stresses using the modal coordinates and modal stresses of the extrapolation points. The Ansys® and Matlab® softwares were used for the numerical analysis and the hot-spot stress calculations, respectively. Findings The proposed methodology/approach to obtain fatigue assessment is based on the modal analysis of the global structural model and local static sub-modelling. The modal analysis was used to extract the boundary conditions to be used in the local model to determine the temporal stresses of the extrapolation points. Based on the modal superposition method, the stresses as function of time were obtained for fatigue life evaluation of a critical detail by the hot-spot stress approach. The detail was studied in three different positions. Originality/value In the present study, a global-local fatigue methodology based on dynamic analysis of the global structural model and local static sub-modelling of the critical detail using the hot-spot stress approach is proposed. Herein, the modal analysis of the global structural model supported by the modal superposition method was used to obtain the matrix of modal coordinates. The static analysis of the local sub-model for each mode from the modal analysis of global structural model was done to estimate the hot-spot stresses. The fatigue damage calculation was based on S-N curve of the critical detail and rainflow method. The IIW recommendation proved to be more conservative compared to the proposed rules in the Eurocode EN 1993-1-9. The global-local modelling based on dynamic analysis is an important and effective tool for fatigue evaluation in welded joints.

Structural and Dynamic Behavior of Pretwisted Rods and Beams

1991 ◽  
Vol 44 (12) ◽  
pp. 483-515 ◽  
Author(s):  
Aviv Rosen
Keyword(s):  
Composite Materials ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Static Analysis ◽  
High Temperatures ◽  
The Other ◽  
Present Review ◽  
Structural Elements ◽  
Coupling Effects ◽  
Very High

Because of being important structural elements in many engineering applications on one hand, and presenting inherent complicated coupling effects on the other hand, pretwisted rods have attracted the interest of many researchers. During the years, as a result of engineering breakthroughs, like the introduction of composite materials or operating at very high temperatures, the problems associated with pretwisted rods became more complicated. The present review will present the research during the last fifty years. It will be divided into three main subjects: static analysis, dynamic analysis and stability problems. The review will concentrate on the structural and dynamic aspects of pretwisted rods. Derivations of models and solution techniques will be addressed.

scholarly journals Hypervisor-assisted dynamic malware analysis

Cybersecurity ◽  
2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Roee S. Leon ◽  
Michael Kiperberg ◽  
Anat Anatey Leon Zabag ◽  
Nezer Jacob Zaidenberg
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Cyber Security ◽  
Malware Analysis ◽  
Analysis Tools ◽  
Significant Performance

AbstractMalware analysis is a task of utmost importance in cyber-security. Two approaches exist for malware analysis: static and dynamic. Modern malware uses an abundance of techniques to evade both dynamic and static analysis tools. Current dynamic analysis solutions either make modifications to the running malware or use a higher privilege component that does the actual analysis. The former can be easily detected by sophisticated malware while the latter often induces a significant performance overhead. We propose a method that performs malware analysis within the context of the OS itself. Furthermore, the analysis component is camouflaged by a hypervisor, which makes it completely transparent to the running OS and its applications. The evaluation of the system’s efficiency suggests that the induced performance overhead is negligible.

Real-time trajectory tracking control of Stewart platform using fractional order fuzzy PID controller optimized by particle swarm algorithm

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zafer Bingul ◽  
Oguzhan Karahan
Keyword(s):  
Dynamic Model ◽  
Fractional Order ◽  
Trajectory Tracking ◽  
Tracking Control ◽  
Fuzzy Pid ◽  
Simulation Environment ◽  
Trajectory Tracking Control ◽  
Content Type ◽  
Control Approach ◽  
Coupling Dynamic

Purpose The purpose of this paper is to address a fractional order fuzzy PID (FOFPID) control approach for solving the problem of enhancing high precision tracking performance and robustness against to different reference trajectories of a 6-DOF Stewart Platform (SP) in joint space. Design/methodology/approach For the optimal design of the proposed control approach, tuning of the controller parameters including membership functions and input-output scaling factors along with the fractional order rate of error and fractional order integral of control signal is tuned with off-line by using particle swarm optimization (PSO) algorithm. For achieving this off-line optimization in the simulation environment, very accurate dynamic model of SP which has more complicated dynamical characteristics is required. Therefore, the coupling dynamic model of multi-rigid-body system is developed by Lagrange-Euler approach. For completeness, the mathematical model of the actuators is established and integrated with the dynamic model of SP mechanical system to state electromechanical coupling dynamic model. To study the validness of the proposed FOFPID controller, using this accurate dynamic model of the SP, other published control approaches such as the PID control, FOPID control and fuzzy PID control are also optimized with PSO in simulation environment. To compare trajectory tracking performance and effectiveness of the tuned controllers, the real time validation trajectory tracking experiments are conducted using the experimental setup of the SP by applying the optimum parameters of the controllers. The credibility of the results obtained with the controllers tuned in simulation environment is examined using statistical analysis. Findings The experimental results clearly demonstrate that the proposed optimal FOFPID controller can improve the control performance and reduce reference trajectory tracking errors of the SP. Also, the proposed PSO optimized FOFPID control strategy outperforms other control schemes in terms of the different difficulty levels of the given trajectories. Originality/value To the best of the authors’ knowledge, such a motion controller incorporating the fractional order approach to the fuzzy is first time applied in trajectory tracking control of SP.

Research on mechanism configuration and dynamic characteristics for multi-split transmission line mobile robot

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wei Jiang ◽  
Yating Shi ◽  
Dehua Zou ◽  
Hongwei Zhang ◽  
Hong Jun Li
Keyword(s):  
Mobile Robot ◽  
Transmission Line ◽  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Transmission Lines ◽  
Dynamic Models ◽  
Working Environment ◽  
Joint Torque ◽  
Content Type ◽  
Working Space

Purpose The purpose of this paper is to achieve the optimal system design of a four-wheel mobile robot on transmission line maintenance, as the authors know transmission line mobile robot is a kind of special robot which runs on high-voltage cable to replace or assist manual power maintenance operation. In the process of live working, the manipulator, working end effector and the working environment are located in the narrow space and with heterogeneous shapes, the robot collision-free obstacle avoidance movement is the premise to complete the operation task. In the simultaneous operation, the mechanical properties between the manipulator effector and the operation object are the key to improve the operation reliability. These put forward higher requirements for the mechanical configuration and dynamic characteristics of the robot, and this is the purpose of the manuscript. Design/methodology/approach Based on the above, aiming at the task of tightening the tension clamp for the four-split transmission lines, the paper proposed a four-wheel mobile robot mechanism configuration and its terminal tool which can adapt to the walking and operation on multi-split transmission lines. In the study, the dynamic models of the rigid robot and flexible transmission line are established, respectively, and the dynamic model of rigid-flexible coupling system is established on this basis, the working space and dynamic characteristics of the robot have been simulated in ADAMS and MATLAB. Findings The research results show that the mechanical configuration of this robot can complete the tightening operation of the four-split tension clamp bolts and the motion of robot each joint meets the requirements of driving torque in the operation process, which avoids the operation failure of the robot system caused by the insufficient or excessive driving force of the robot joint torque. Originality/value Finally, the engineering practicability of the mechanical configuration and dynamic model proposed in the paper has been verified by the physical prototype. The originality value of the research is that it has double important theoretical significance and practical application value for the optimization of mechanical structure parameters and electrical control parameters of transmission line mobile robots.

scholarly journals Investigation of Data Dependencies by Dynamic Analysis of Sapfor

2020 ◽  
Vol 23 (3) ◽  
pp. 473-493
Author(s):  
Nikita Andreevich Kataev ◽  
Alexander Andreevich Smirnov ◽  
Andrey Dmitrievich Zhukov
Keyword(s):  
Dynamic Analysis ◽  
Programming Languages ◽  
Static Analysis ◽  
Automatic Parallelization ◽  
Parallel Execution ◽  
Control Flow ◽  
Analysis Tool ◽  
Data Dependencies ◽  
Program Parallelization ◽  
Memory Accesses

The use of pointers and indirect memory accesses in the program, as well as the complex control flow are some of the main weaknesses of the static analysis of programs. The program properties investigated by this analysis are too conservative to accurately describe program behavior and hence they prevent parallel execution of the program. The application of dynamic analysis allows us to expand the capabilities of semi-automatic parallelization. In the SAPFOR system (System FOR Automated Parallelization), a dynamic analysis tool has been implemented, based on on the instrumentation of the LLVM representation of an analyzed program, which allows the system to explore programs in both C and Fortran programming languages. The capabilities of the static analysis implemented in SAPFOR are used to reduce the overhead program execution, while maintaining the completeness of the analysis. The use of static analysis allows to reduce the number of analyzed memory accesses and to ignore scalar variables, which can be explored in a static way. The developed tool was tested on performance tests from the NAS Parallel Benchmarks package for C and Fortran languages. The implementation of dynamic analysis, in addition to traditional types of data dependencies (flow, anit, output), allows us to determine privitizable variables and a possibility of pipeline execution of loops. Together with the capabilities of DVM and OpenMP these greatly facilitates program parallelization and simplify insertion of the appropriate compiler directives.

scholarly journals Hybrid-Based Analysis Impact on Ransomware Detection for Android Systems

2021 ◽  
Vol 11 (22) ◽  
pp. 10976
Author(s):  
Rana Almohaini ◽  
Iman Almomani ◽  
Aala AlKhayer
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Hybrid System ◽  
State Of The Art ◽  
Detection System ◽  
Detection Accuracy ◽  
Accuracy Rate ◽  
Hybrid Detection ◽  
Dynamic Analyses ◽  
Data Files

Android ransomware is one of the most threatening attacks that is increasing at an alarming rate. Ransomware attacks usually target Android users by either locking their devices or encrypting their data files and then requesting them to pay money to unlock the devices or recover the files back. Existing solutions for detecting ransomware mainly use static analysis. However, limited approaches apply dynamic analysis specifically for ransomware detection. Furthermore, the performance of these approaches is either poor or often fails in the presence of code obfuscation techniques or benign applications that use cryptography methods for their APIs usage. Additionally, most of them are unable to detect ransomware attacks at early stages. Therefore, this paper proposes a hybrid detection system that effectively utilizes both static and dynamic analyses to detect ransomware with high accuracy. For the static analysis, the proposed hybrid system considered more than 70 state-of-the-art antivirus engines. For the dynamic analysis, this research explored the existing dynamic tools and conducted an in-depth comparative study to find the proper tool to integrate it in detecting ransomware whenever needed. To evaluate the performance of the proposed hybrid system, we analyzed statically and dynamically over one hundred ransomware samples. These samples originated from 10 different ransomware families. The experiments’ results revealed that static analysis achieved almost half of the detection accuracy—ranging around 40–55%, compared to the dynamic analysis, which reached a 100% accuracy rate. Moreover, this research reports some of the high API classes, methods, and permissions used in these ransomware apps. Finally, some case studies are highlighted, including failed running apps and crypto-ransomware patterns.

Analysis and Control of Unknown In-Vehicle Network System

2012 ◽  
Vol 184-185 ◽  
pp. 1521-1525
Author(s):  
Yu En Wu ◽  
Yu Hui Hu ◽  
Ya Ying Jin ◽  
Jun Qiang Xi
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Effective Control ◽  
Hybrid Powertrain ◽  
Verification Method ◽  
Gateway System ◽  
Powertrain System ◽  
Analytical Protocol ◽  
Key Aspects ◽  
And Control

A CAN-Bus protocol analysis and verification method with three key aspects which are static analysis, dynamic analysis and verification &control is put forward. Static analysis ascertains the communication information of each node by bus residual method; Synchronous contrast method is put in use to obtain practical and effective control protocol in the dynamic analysis; Verification &control is to verify the correctness of the analytical protocol and to achieve the control of the critical subsystems by bus gateway system. This scheme has been used to analyze a foreign parallel hybrid powertrain system, and it proves the correctness of the designed static analysis and dynamic analysis, the applicability of verification &control.

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