Dynamic Force and Torque Analysis of a Spherical Four-Bar Mechanism

1995 ◽  
Author(s):  
J. R. Dooley
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Force ◽  
Accurate Model ◽  
Dynamic Analyses ◽  
Torque Analysis

Abstract Spherical four-bar linkages are compact mechanisms capable of motion outside the plane and transmission between intersecting shafts. Dynamic analyses of spherical four-bar linkages are complicated by the fact that they are statically indeterminate. Previous solutions have used an RCCC approximation to model the 4R linkage. This paper extends previous results to include the material elasticity in the dynamic analysis. The results of this more accurate model are compared to those obtained from the RCCC model and it is shown that the RCCC approximation yields significant errors.

Dynamic Force and Torque Analysis of Spherical Four Link Mechanisms

1983 ◽  
Vol 105 (3) ◽  
pp. 492-497 ◽  
Author(s):  
A. T. Yang ◽  
Sun Zhishang
Keyword(s):  
Dynamic Analysis ◽  
Optimum Design ◽  
Mass Distribution ◽  
High Speed ◽  
Dynamic Force ◽  
Arbitrary Mass ◽  
Link Mechanism ◽  
Torque Analysis ◽  
Analytical Expressions

In this paper we present a dynamic analysis of a general spherical four-link mechanism whose links have arbitrary mass distribution. Results, which are in explicit analytical expressions in terms of inertia-induced forces and moments in links, are useful for optimum design of the mechanism under high-speed operation.

Dynamic Force and Torque Analysis of Mechanisms Using Dual Vectors and 3 × 3 Screw Matrix

1972 ◽  
Vol 94 (2) ◽  
pp. 738-745 ◽  
Author(s):  
Cemil Bagci
Keyword(s):  
Rate Of Change ◽  
Inertia Force ◽  
Dynamic Force ◽  
Equilibrium Equations ◽  
Force Vector ◽  
Time Rate ◽  
Output Force ◽  
Dynamic Analyses ◽  
Torque Analysis ◽  
Space Mechanisms

The method of determining dynamic force and torque distributions in mechanisms by using dual vectors and 3 × 3 screw matrix is presented. The dual equilibrium equations for each moving link of a mechanism are written as a null resultant dual force vector in a reference system located on the link. The resulting 6 × (n – 1) equilibrium equations for an n-link mechanism are solved for the unknown force and torque components at the pair locations, and for the input force or torque required to drive the mechanism to produce the specified dual output force. The dynamics of the mechanism is governed by introducing the dual inertia force acting on a link, which is determined as the negative of the time rate of change in the dual momentum of the link due to its own mass and mass moments of inertia, in the dual equilibrium equation for that link. Dynamic analyses of the 4R plane and the RCCC space mechanisms are performed. Dynamic transmissivities are defined. The RCCC mechanism is analyzed in a numerical example and the results of the dynamic distributions are compared with those of static distributions.

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.

Dynamic Shock Analysis of Shipboard Equipment

1967 ◽  
Vol 4 (04) ◽  
pp. 331-354
Author(s):  
R. L. Harrington ◽  
W. S. Vorus
Keyword(s):  
Mathematical Models ◽  
Dynamic Analysis ◽  
Analysis Method ◽  
Dynamic Analyses ◽  
Shock Resistance ◽  
Computational Procedures

A description and evaluation of the dynamic analysis method of determining the shock resistance of shipboard equipment is given. Development of equipment mathematical models is treated in detail, and the computational procedures used in conducting dynamic analyses are illustrated. Considerations in the preparation of dynamic-analysis reports are discussed. Discussers R. S. Adelizzi G. W. Bishop V. T. Boatwright K. J. Calvin C. Dotson Capt. H. C. Field, Jr., USND. W. Ginter O. Gould D. M. Gray K. Gyswyt R. T. Hawley RADM L. V. Honsinger, USN(Ret.) C. Lee J. C. Lester C. Li W. A. Littlejohn N. J. Monroe A. Morrone B. Novak E. W. Palmer C. G. Puffenburger L. L. Salter H.M. Schauer J. R. Sullivan J. D. Swannack C. Y. Tiao H. H. Ward W. P. Welch J. B. Woodward, III

Dynamic Analysis of Slider Mechanisms With Consideration of Frictional Effect in the Slider

2018 ◽  
Author(s):  
Jianyou Han ◽  
Yang Cao ◽  
Penghao Li
Keyword(s):  
Dynamic Analysis ◽  
Friction Force ◽  
Center Of Mass ◽  
Frictional Effect ◽  
Hinge Point ◽  
Shear Mechanism ◽  
Dynamic Analyses ◽  
Rotation Motion ◽  
Application Scope

This paper deals with dynamic analysis of three methods for the slider in mechanisms. Three methods are introduced under three conditions (the influence of friction force is considered, the slider’s center of mass is not coincide with the hinge point, the slider and its guide have rotation motion). The dynamic analyses of the crank slider mechanism and the flying shear mechanism are given as examples by a developed software based on Visual C++ environment, and application scope of the three methods is concluded at the end of the paper. These results are useful for analyzing and designing mechanisms with sliders, such as choosing suitable slider materials or actuators.

The Impact of Nudging in the Meteorological Model for Retrospective Air Quality Simulations. Part II: Evaluating Collocated Meteorological and Air Quality Observations

2008 ◽  
Vol 47 (7) ◽  
pp. 1868-1887 ◽  
Author(s):  
Tanya L. Otte
Keyword(s):  
Air Quality ◽  
Dynamic Analysis ◽  
Air Quality Modeling ◽  
Shortwave Radiation ◽  
Error Patterns ◽  
Ozone Prediction ◽  
Quality Modeling ◽  
Dynamic Analyses ◽  
The Impact ◽  
Over Time

Abstract For air quality modeling, it is important that the meteorological fields that are derived from meteorological models reflect the best characterization of the atmosphere. It is well known that the accuracy and overall representation of the modeled meteorological fields can be improved for retrospective simulations by creating dynamic analyses in which Newtonian relaxation, or “nudging,” is used throughout the simulation period. This article, the second of two parts, provides additional insight into the value of using nudging-based data assimilation for dynamic analysis in the meteorological fields for air quality modeling. Meteorological simulations are generated by the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) using both the traditional dynamic analysis approach and forecasts for a summertime period. The resultant meteorological fields are then used for emissions processing and air quality simulations using the Community Multiscale Air Quality Modeling System (CMAQ). The predictions of surface and near-surface meteorological fields and ozone are compared with a small network of collocated meteorological and air quality observations. Comparisons of 2-m temperature, 10-m wind speed, and surface shortwave radiation show a significant degradation over time when nudging is not used, whereas the dynamic analyses maintain consistent statistical scores over time for those fields. Using nudging in MM5 to generate dynamic analyses, on average, leads to a CMAQ simulation of hourly ozone with smaller error. Domainwide error patterns in specific meteorological fields do not directly or systematically translate into error patterns in ozone prediction at these sites, regardless of whether nudging is used in MM5, but large broad-scale errors in shortwave radiation prediction by MM5 directly affect ozone prediction by CMAQ at specific sites.

Translation Motion and Dynamic Analysis of Ancient Architecture

2012 ◽  
Vol 253-255 ◽  
pp. 3-7
Author(s):  
Tie Cheng Wang ◽  
Liang Zhang ◽  
Hai Long Zhao
Keyword(s):  
Energy Dissipation ◽  
Free Vibration ◽  
Dynamic Analysis ◽  
Dynamic Force ◽  
Vibration Period ◽  
Translation Motion ◽  
Energy Dissipation Capacity ◽  
The Right ◽  
Jacking Force ◽  
The Temple

Reasonable formula of jacking force and scientific dynamic analysis has an important contribution to guide the building monolithic moving Engineering. In this paper, take the temple as an example to study building monolithic movement. It is shown in the analysis results of SAP2000 that the mortise-tenon joints (in the wooden structure) has a significant influence in improving the energy dissipation capacity, prolonging the structural free vibration period,minimizing the dynamic response of structure. The acceleration of all the joints tends to be in consistent under the dynamic force effect. The structure has enough safety capacity within the right displacement margin for joints.

Stress Analysis on an Automotive Coil Spring Driven on Flat, Uphill, and Downhill Road Surfaces

2021 ◽  
Vol 892 ◽  
pp. 124-128
Author(s):  
Harahap Jagodang ◽  
Husaini ◽  
Edisah Putra Teuku ◽  
Dieter Schramm
Keyword(s):  
Carbon Steel ◽  
Dynamic Analysis ◽  
Stress Analysis ◽  
Maximum Stress ◽  
Road Surface ◽  
Coil Spring ◽  
Vehicle Load ◽  
Road Surfaces ◽  
Dynamic Analyses

This study aims to analyze the stress that occurred on the automotive coil spring made of SAE 5160 carbon steel due to various types of road surfaces. The 60-second strain signals measured on a coil spring of a car being driven on a flat, uphill, and downhill road surface were used as the loads in these dynamic analyses. The analysis results showed that the maximum stress occurred on the inside of the spring in the second coil from the top. The results of this dynamic analysis also showed that the three types of road surfaces provided almost the same stress. The downhill road surface gave the highest stress, which was 0.622 GPa, followed by flat road (0.621 GPa) and uphill road (0.62 GPa). The reasons for this are the shifting of the vehicle load to the front wheels together with the braking effect when driving downhill.

Dynamic Analysis of FRP-Reinforced Masonry Arches via a No-Tension Model with Damage

2014 ◽  
Vol 624 ◽  
pp. 619-626 ◽  
Author(s):  
Massimiliano Lucchesi ◽  
Barbara Pintucchi ◽  
Nicola Zani
Keyword(s):  
Dynamic Analysis ◽  
Beam Model ◽  
Normal Stresses ◽  
Masonry Arches ◽  
Irreversible Damage ◽  
Static And Dynamic Analysis ◽  
Reinforced Masonry ◽  
Composite Interface ◽  
Dynamic Analyses

A FE beam model to perform static and dynamic analysis of fiber-reinforced masonry arches is presented. Based on a constitutive equation formulated for no-tension masonry beams, the model accounts for a limit to the material deformability and provides for irreversible damage occurring under compression. In order to capture any possible FRP debonding, a procedure is also formulated to reduce the performance of the fiber when the tangential and normal stresses at the masonry-composite interface reach a critical value. Some dynamic analyses are performed on a case study with the aim of evaluating the effectiveness of FRP-retrofitting in improving seismic performances.

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