A Study on the Combined Effect of Axle Friction and Rolling Resistance

2003 ◽  
Vol 31 (2) ◽  
pp. 101-107 ◽  
Author(s):  
Murat Sönmez
Keyword(s):  
Dry Friction ◽  
Engineering Students ◽  
Rolling Resistance ◽  
Combined Effect ◽  
Synthesis Problem ◽  
Free Body Diagram ◽  
Free Body ◽  
The Given ◽  
Diagram Analysis

Many textbooks on mechanics for engineering students and engineers consider the concepts of rolling resistance and axle friction separately, expecting readers to combine the given analysis for each of them in determining, for instance, the magnitude of the force needed to move a railroad car. However, this requires a thorough free-body diagram analysis and, since examples are not typically included in the textbooks, students may have difficulty solving such problems. This study represents the solution of the problem in terms of both the dry axle friction and the rolling resistance. It is also suggested as a good synthesis problem that may be considered in teaching the effect of dry friction to engineering students.

Mechanix: A natural sketch interface tool for teaching truss analysis and free-body diagrams

2014 ◽  
Vol 28 (2) ◽  
pp. 169-192 ◽  
Author(s):  
Olufunmilola Atilola ◽  
Stephanie Valentine ◽  
Hong-Hoe Kim ◽  
David Turner ◽  
Erin McTigue ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Engineering Students ◽  
Online Courses ◽  
Teaching Method ◽  
Tutoring Systems ◽  
Online Systems ◽  
Constructive Feedback ◽  
Domain Specific ◽  
Free Body Diagram ◽  
Free Body

AbstractMassive open online courses, online tutoring systems, and other computer homework systems are rapidly changing engineering education by providing increased student feedback and capitalizing upon online systems' scalability. While online homework systems provide great benefits, a growing concern among engineering educators is that students are losing both the critical art of sketching and the ability to take a real system and reduce it to an accurate but simplified free-body diagram (FBD). For example, some online systems allow the drag and drop of forces onto FBDs, but they do not allow the user to sketch the FBDs, which is a vital part of the learning process. In this paper, we discuss Mechanix, a sketch recognition tool that provides an efficient means for engineering students to learn how to draw truss FBDs and solve truss problems. The system allows students to sketch FBDs into a tablet computer or by using a mouse and a standard computer monitor. Using artificial intelligence, Mechanix can determine not only the component shapes and features of the diagram but also the relationships between those shapes and features. Because Mechanix is domain specific, it can use those relationships to determine not only whether a student's work is correct but also why it is incorrect. Mechanix is then able to provide immediate, constructive feedback to students without providing final answers. Within this manuscript, we document the inner workings of Mechanix, including the artificial intelligence behind the scenes, and present studies of the effects on student learning. The evaluations have shown that Mechanix is as effective as paper-and-pencil-based homework for teaching method of joints truss analysis; focus groups with students who used the program have revealed that they believe Mechanix enhances their learning and that they are highly engaged while using it.

Method for Estimating Speed of the Out-of-Control Tractor-Semitrailer on Downhill Grades

2021 ◽  
pp. 036119812110242
Author(s):  
Menghua Yan ◽  
Jinliang Xu ◽  
Shuo Han ◽  
Yaping Dong ◽  
Leyu Wei
Keyword(s):  
Traffic Safety ◽  
Rolling Resistance ◽  
Road Surface ◽  
Independent Variables ◽  
Free Body Diagram ◽  
Newton’S Laws ◽  
Laws Of Motion ◽  
Free Body ◽  
Safety Features ◽  
Truck Weight

Speed estimation for the out-of-control truck on a downhill grade is essential for passive safety features like truck escape ramps to promote traffic safety. This paper presents a method for estimating the speed of out-of-control trucks based on Newton’s Laws of Motion. First of all, we analyze gravity effort, aerodynamics, and rolling resistance through a free body diagram of an out-of-control truck on a downhill grade. Further, we select the speed as the dependent variable, with the following road and vehicle characteristics as independent variables: road surface type, grade, grade length, truck size, truck weight, and tire type. Finally, we estimate the speed and acceleration according to Newton’s Laws of Motion. The results show that the factors that significantly affect the out-of-control truck’s speed include tire type, road surface coefficient, grade, and grade length. TruckMaker simulation results demonstrate that the model is valid at a 99% confidence level.

scholarly journals Synthesizing Argumentation Frameworks from Examples

2019 ◽  
Vol 66 ◽  
pp. 503-554 ◽  
Author(s):  
Andreas Niskanen ◽  
Johannes Wallner ◽  
Matti Järvisalo
Keyword(s):  
Natural Extension ◽  
Research Abstract ◽  
Expressive Power ◽  
Synthesis Problem ◽  
Constraint Optimization ◽  
Abstract Argumentation ◽  
Central Notion ◽  
Definition Of ◽  
The Given ◽  
Representation Formalism

Argumentation is today a topical area of artificial intelligence (AI) research. Abstract argumentation, with argumentation frameworks (AFs) as the underlying knowledge representation formalism, is a central viewpoint to argumentation in AI. Indeed, from the perspective of AI and computer science, understanding computational and representational aspects of AFs is key in the study of argumentation. Realizability of AFs has been recently proposed as a central notion for analyzing the expressive power of AFs under different semantics. In this work, we propose and study the AF synthesis problem as a natural extension of realizability, addressing some of the shortcomings arising from the relatively stringent definition of realizability. In particular, realizability gives means of establishing exact conditions on when a given collection of subsets of arguments has an AF with exactly the given collection as its set of extensions under a specific argumentation semantics. However, in various settings within the study of dynamics of argumentation---including revision and aggregation of AFs---non-realizability can naturally occur. To accommodate such settings, our notion of AF synthesis seeks to construct, or synthesize, AFs that are semantically closest to the knowledge at hand even when no AFs exactly representing the knowledge exist. Going beyond defining the AF synthesis problem, we study both theoretical and practical aspects of the problem. In particular, we (i) prove NP-completeness of AF synthesis under several semantics, (ii) study basic properties of the problem in relation to realizability, (iii) develop algorithmic solutions to NP-hard AF synthesis using the constraint optimization paradigms of maximum satisfiability and answer set programming, (iv) empirically evaluate our algorithms on different forms of AF synthesis instances, as well as (v) discuss variants and generalizations of AF synthesis.

Dynamics of Mechanical Systems and the Generalized Free-Body Diagram—Part I: General Formulation

2008 ◽  
Vol 75 (6) ◽  
Author(s):  
József Kövecses
Keyword(s):  
Configuration Space ◽  
Dynamic Equilibrium ◽  
Mechanical Systems ◽  
Constrained Systems ◽  
Dynamic Equations ◽  
Analytical Mechanics ◽  
Constrained Motion ◽  
Equilibrium Equations ◽  
Free Body Diagram ◽  
Free Body

In this paper, we generalize the idea of the free-body diagram for analytical mechanics for representations of mechanical systems in configuration space. The configuration space is characterized locally by an Euclidean tangent space. A key element in this work relies on the relaxation of constraint conditions. A new set of steps is proposed to treat constrained systems. According to this, the analysis should be broken down to two levels: (1) the specification of a transformation via the relaxation of the constraints; this defines a subspace, the space of constrained motion; and (2) specification of conditions on the motion in the space of constrained motion. The formulation and analysis associated with the first step can be seen as the generalization of the idea of the free-body diagram. This formulation is worked out in detail in this paper. The complement of the space of constrained motion is the space of admissible motion. The parametrization of this second subspace is generally the task of the analyst. If the two subspaces are orthogonal then useful decoupling can be achieved in the dynamics formulation. Conditions are developed for this orthogonality. Based on this, the dynamic equations are developed for constrained and admissible motions. These are the dynamic equilibrium equations associated with the generalized free-body diagram. They are valid for a broad range of constrained systems, which can include, for example, bilaterally constrained systems, redundantly constrained systems, unilaterally constrained systems, and nonideal constraint realization.

scholarly journals Modeling and Validation of 2-DOF Rail Vehicle Model Based on Electro–Mechanical Analogy Theory Using Theoretical and Experimental Methods

2018 ◽  
Vol 8 (6) ◽  
pp. 3603-3608
Author(s):  
F. Pehlivan ◽  
C. Mizrak ◽  
I. Esen
Keyword(s):  
Degrees Of Freedom ◽  
Similarity Theory ◽  
Equations Of Motion ◽  
Vehicle Model ◽  
Rail Vehicle ◽  
Free Body Diagram ◽  
Model Transfer ◽  
Simulation Results ◽  
Free Body ◽  
Secondary Suspension

This paper presents theoretical and experimental results on modeling and simulation of two degrees of freedom rail vehicle by using electro-mechanical similarity theory. In this study, the equations of motion were derived using Newton’s second law of motion and then mechanical and equivalent electrical circuits were obtained with the help of a free body diagram. A schema in Simulink allowing analyzing of the behavior of the primary and secondary suspension was created. In order to verify the electrical model, transfer function and schema were developed in Simulink. The simulation results were compared with the experimental data and the comparison showed that the results of the mechanical experiments were close to the simulation results, but the electrical results showed better periodic behavior.

scholarly journals The Visualizations Methods of Geometrical Forms in teaching of Civil Engineering Students

2015 ◽  
Vol 2 ◽  
pp. 312 ◽  
Author(s):  
Zoja Veide ◽  
Veronika Strozheva
Keyword(s):  
Engineering Students ◽  
Civil Engineering ◽  
Three Dimensional ◽  
Practical Experience ◽  
Spatial Skills ◽  
Three Dimensional Objects ◽  
Geometric Problems ◽  
Compulsory Subject ◽  
The Given ◽  
Spatial Problems

<p class="R-AbstractKeywords"><span lang="EN-US">Development of spatial representation (the ability to imagine three-dimensional objects using flat pictures or drawings), skills of the intuitive decision of spatial problems and more meaningful use of CAD software are essential for qualified education of students. Visualization of geometric problems helps students to understand and to solve the given geometric tasks. The paper describes types of visualization of geometrical objects from graphic exercises of compulsory subject “Civil Engineering</span><span lang="EN-US">Graphics”. This course is specified for Civil engineering undergraduate 2nd year students of Riga Technical university.</span></p><p class="R-AbstractKeywords"><span lang="EN-US">Performance of a breadboard model, creation of the given model using ArchiCAD and using augmented reality (AR) software are included in the course "Civil Engineering Graphics” assignments. The examples of the tasks of 3D modeling in learning process are presented in this article. AR application allows faster understanding of complicated spatial problems and relationships and was used to entertain the students during the studies. Before mentioned approach was enabled to develop spatial skills of students, facilitate the students to obtain more practical experience in solving graphic exercises and was supposed enhance the quality of graphic education</span><span lang="EN-US">. </span></p><p class="R-AbstractKeywords"><span lang="EN-US"> </span></p>

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