Force Diagram Research Articles

Experimental study on skew inverted-T bent caps with minimum traditional and skew transverse reinforcing

In this paper, the shear behavior of six full-scale Inverted-T Bent Caps (ITBC) specimens with skew angles of 30°, 45°, and 60° are reported to study the effect of skew angle and rebar arrangement on structural performance. The transverse reinforcement in skewed ITBCs is designed as per the traditional methods the TxDOT Bridge Design Manual LRFD, which conform to the AASHTO LRFD Bridge Design Specifications. The traditional design of flaring the transverse rebar in skew ITBCs brings notable difficulty in manufacturing. An alternative way is to apply uniform skewed reinforcing, which is compared to traditional design in this research. The minimum ratio of transverse reinforcement required by AASHTO LRFD specifications was adopted in this research to investigate the most unfavorable design. The load–displacement curves, the internal force diagrams, the strength and displacement capacity, and the strain measuring results are reported in detail. The specimens with a skew angle of 30° or 45° fail in shear-critical mode, while the specimens with a skew angle of 60° fail in torsion-critical mode. The experimental results show that replacing the traditional reinforcement with the skew reinforcement does not reduce the capacity of ITBCs. The cracking behavior of ITBCs with skew rebar are better than the ITBCs with traditional rebar. Based on the extensive experimental study on ITBCs, general design guidelines for the design and construction of the skewed reinforcing in ITBCs are provided.

Modelling and analysis of knee and hip joints in human being

The present work aims at developing a model of knee and hip joint which represents all the forces, by using 'free body diagrams'. In order to do force analysis one needs to study knee and hip anato...

Fracture parameters of alkali-activated aluminosilicate composites with ceramic precursor: durability aspects

Four sets of alkali-activated aluminosilicate (AAAS) composites based on ceramic precursors were studied in terms of their characterization by mechanical fracture parameters as a basis for considerations of durability. AAAS composites made of brick powder as a precursor and alkaline activator with various silicate moduli (Ms = 0.8, 1.0, 1.2, 1.4, and 1.6) were investigated. The sets of AAAS composites differed in terms of the used filler: quartz sand or brick rubble. Two different precursor particle size ranges of 0–1 mm and 0–0.3 mm were used for both types of filler. The test specimens had nominal dimensions of 40 × 40 × 160 mm and were provided with a notch at midspan after 28 days of hardening. The notches were cut up to 1/3 of the height of the specimens. The specimens were subjected to three-point bending fracture tests during which force vs. deflection (F–d) and force vs. crack mouth opening displacement (F–CMOD) diagrams were recorded. Tensile strength ft,ID and specific fracture energy GF,ID values were identified using the inverse method based on a neural network ensemble. The obtained F–CMOD diagrams were subsequently evaluated using the double-K fracture model supported by the ft,ID and GF,ID values. The double-K model allows the quantification of two different levels of crack propagation: initiation, which corresponds to the beginning of stable crack growth, and unstable crack propagation.

Doubts and Amendments to Newton's Third Law

Doubts and Amendments to Newton's Third Law LIM Sau Kong Abstract This article first raises the doubts that scholars have about Newton’s third law, particularly pointed out Newton did not clarify the perspectives of "action" and "reaction" in the third law; do these two words really mean "force" and whether the object in "action" or "reaction" will move. The main purpose of this article is to rectify the third law, and then apply the rectified third law to explain three common cases in physics with the help of free body diagram. Full Text: PDF DOI: 10.15640/ijpa.v9n2a1

Operation modes of frequency converter in the rotor circuit of induction motor drive of a mine hoist

The electric drive of a hoist must ensure the formation of the required tachogram and the diagram of driving forces. The tachogram depends on the type of lifting vehicles. For hoist electric drives based on a wound-rotor induction motor, it is possible to use a frequency converter in the rotor circuit to control the motor speed and torque. When designing a converter, the problem arises of determining the operating modes of its bridges and the current direction between them. The article analyzes the operating modes of the hoisting motor in accordance with various sections of the tachogram of the unit and the connection between the mechanical and electrical coordinates of the drive. The analysis carried out in the work makes it possible to obtain and implement methods for determining the parameters of the frequency converter in the rotor circuit and developing an algorithm for controlling the converter bridges to ensure the required tachogram and driving force diagram.

Dynamic Behavior of an Iron Particle in (Iron-Air) Dust Suspension Crossing the Flame Zones of Combustion

At present article we work on physics and dynamics of iron particles in combustion chamber crossing the flame zones of (iron- air) suspension. In this article we focus on an iron dust free body diagram and forces on it. Gravity forces, drag force from gas and thermopherotic force are these forces on an iron particle. By existing of these forces on a particle, acceleration will be inducted to a particle in flame zones and by solving the differential equation of dynamic equation for a particle with continues boundary condition in velocity curve of dusts in dust- air suspension we can estimate the velocity profile across the flame zones. Theoretical estimation of velocity profile in this study has been compared to an experimental study on velocity and concentration profile of iron particles across the flame propagating through the particles cloud.

Visualization of the Process of Static Buckling of a Micropolar Meshed Cylindrical Panel

Process visualization of static stability loss in mechanics is shown by the micropolar meshed cylindrical panel example with two families of mutually perpendicular ribs. The mathematical model of the panel's behavior is based on the Kirchhoff-Love hypotheses. The micropolar theory is applied to ac-count for scale effects. Geometric nonlinearity is taken into account according to the theory of Theodor von Karman. The mesh structure is taken into account based on the Pshenichnov I. G. continuum model. Visualization of numerical results using Autodesk 3ds Max software made it possible to more clearly assess the phenomenon of static buckling of the shell in question. Visualization of the results using 3D made it possible to establish that an in-crease in the distance between the edges of the mesh panel and an increase in the parameter depending on the size does not change the bending shape of the panel, as well as the diagrams of moments and forces at subcritical and supercritical loads.

Relation of the average interaction field with the coercive and interaction field distributions in First order reversal curve diagrams of nanowire arrays

First-order reversal curve diagrams, or FORC diagrams, have been studied to determine if the widths of their distributions along the interaction and coercivity axes can be related to the mean-field magnetization dependent interaction field (MDIF). Arrays of nanowires with diameters ranging from 18 up to 100 nm and packing fractions varying from 0.4 to 12% have been analyzed. The mean-field MDIF has been measured using the remanence curves and used as a measuring scale on the FORC diagrams. Based on these measurements, the full width of the interaction field distribution and the full width at half maximum (FWHM) of the FORC distribution profile along the interaction field direction are shown to be proportional to the MDIF, and the relation between them is found. Moreover, by interpreting the full width of the coercive field distribution in terms of the dipolar induced shearing, a simple relation is found between the width of this distribution and the MDIF. Furthermore, we show that the width of the FORC distribution along the coercive field axis is equal to the width of the switching field distribution obtained by the derivation of the DC remanence curve. This was further verified with the switching field distribution determined using in-field magnetic force microscopy (MFM) for very low density nanowires. The results are further supported by the good agreement found between the experiments and the values calculated using the mean-field model, which provides analytical expressions for both FORC distributions.

Momentum Vector Diagrams

Collisions are real-world situations from everyday life (such as car crashes, playing billiards, etc.) that can be described and understood by the principle of conservation of momentum. One might expect that learning from simple collisions might help students understand more complicated physical phenomena. However, from our teaching experiences we often find that even in a physics problem involving a simple physics collision, students have trouble arriving at the correct answer. Multiple representations are tools to help students think and act like physicists when solving problems. Examples of these representations are motion diagrams, free-body diagrams, energy bar charts, impulse-momentum bar charts, and impulse-momentum diagrams. Impulse-momentum diagrams were designed to help students understand the principle of conservation of momentum. They effectively show the magnitude of the momentum but are limited to only problems in one dimension. In this paper we will show a structured teaching method using momentum vector diagrams (MVD) as a tool. The MVD method is developed to help students understand the principle of conservation of momentum and vector property of momentum, and to be able to use it to solve collision problems especially in two dimensions.

The role of FeCo and FeCoCr nanowires array on the formation of single phase bi-magnets

Nanowire (NWs) arrays of FeCo and FeCoCr were prepared by AC pulsed electrodeposition embedded into an alumina template. They were then employed as an underlayer to provide the dot array of cobalt ferrite thin films. Highly ordered arrays of NWs with the diameter of 30 nm and length of 10 µm were fabricated and then annealed in various environments. The cobalt ferrite thin films were deposited by the sputtering approach with the almost constant thickness of 70 nm as the hard magnetic phase. The combination of FeCo and cobalt ferrite could provide an exchange spring magnet with the magnetic coupling feature. X-ray diffraction (XRD) patterns of the NW arrays indicated the formation of the body centered cubic (bcc) FeCo phase with [110] texture. Field emission electron microscopy (FESM) equipped by EDS also characterized the morphological features and elemental composition. Magnetization and coercivity of NWs were examined using the vibrating sample magnetometer. The maximum coercivity of NWs array is 2950 Oe which is related to H2 annealing FeCo NWs array. The magnetization reversal process of the as-deposited and annealed FeCo and FeCoCr NWs arrays was performed by angular dependence coercivity and squareness. Further, FORC diagrams indicated an interacting single domain behavior for as-deposited FeCo NWs and a weakly-interacting single domain state for the annealed samples. The morphological and structural features of cobalt ferrite were also studied by XRD, FE-SEM and AFM techniques. It was found that the cobalt ferrite dot array with a uniform chemical composition and structure was formed. The inter-diffusion of atoms between underlayer and thin films was confirmed by EDS. The maximum coercivity of the nanocompsite was 5800 Oe that is obtained for FeCoCr underlayer with argon annealing. The VSM analysis showed that sufficient exchange coupling was formed by using the FeCoCr underlayer in hydrogen annealing, while argon annealing provided a kink in the hysteresis loops. The obtained nanocomposites could be, therefore, considered as the potential candidate for use in the exchange spring magnet.

Geometry for design: approaches to the study of representation and dimension and their contributions to the modeling of phenomena

The difficulties of representation and understanding of the dimension are evident in the different educational levels. University education is no stranger to this situation. This communication was developed within the framework of the graphic design course. This course was designed under the use of specialized software in geometry, which was freely available and intuitive. It should be remembered that the adequate use of representations and attributes proper to the dimension aids in the representations of movement phenomena, as well as in the representations in force diagrams in the teaching of physics. This qualitative research aims to address aspects of representation and dimensionality from the description of some selected tasks of the group participants, who contrast the first representations, with their final activities. That is, these representations showed their evolution in construction, to the extent that the flat representations of objects in the portfolio were built in real dimensions, keeping the proportional relationship between its parts.

A Graphical Method for Determining Truss Stability

Graphic statics has been used for over 150 years, having been pioneered by the likes of Maxwell, Cremona, Culmann and Rankine, and has recently seen a resurgence in popularity because of its use in design. However, it is only concerned with equilibrium; as any engineer will testify, whilst equilibrium is necessary, it is not sufficient and stability must also be obtained. This paper develops a novel graphical method for determining the stability and stiffness of prestressable structures. By considering the weighted sum of the Maxwell-Minkowski diagram, the stiffness and stability of the structural mechanisms can be determined. This work extends to cover structures with multiple mechanisms and has been compared to results obtained through experimentation and the finite element method. Furthermore, it extends the work on stiffness to provide a graphical method to estimate the natural frequency of a truss. Whilst this method accurately determines the stiffness of structures, it represents a significant development in the field of graphic statics as it allows an engineer to 'eye-ball' the stability of a given truss. Engineers can also manipulate the form and force diagrams, as desired, to adjust the stiffness of their structure accordingly, whilst being able to visualise the process. Much of the previous work in this area relies heavily upon large matrices, while this method allows a more intimate and hands-on alternative.

РАСЧЕТ РЕЙСОВОГО ГРУЗОВОГО ПЛАНА КОНТЕЙНЕРОВОЗА

The questions of drafting of cargo plan of containership on a voyage are considered in work, duting of which the reception and unloading of parties of containers is produced in a few ports. Forming of loading of the ship «Sky Gemini », which can adopt containers in eight holds and on their lids is considered. Placing of containers can be produced in 16 cargo apartments, thus in each of cargo apartment it is possible to place 192 twenty foot container. The voyage of ship with arrival in five ports is considered in the article, thus in the first port the complete loading of ship is produced 3072 containers, gross weight of which makes 45000 т. A load consists of three parties which are addressed accordingly in fifth, fourth and second ports. In the second port the second party and ship unloads with two remaining parties follows in the third port, where fourth party of containers for fourth port is loaded. Unloading of the third and fourth parties is produced in fourth port, and a ship with the unique first party accomplishes transition in the last fifth port. As a result of every loading of parties of containers list of ship must be in limits from 0 to -2,0 м. List, which placing of containers, suiting longitudinal durability, corresponds to, gets out from the indicated interval. Therefore, for every party of loading it is necessary to find the scope values of static moments which provide list of ship accordingly 0 and -2,0 м. The results of imitation design of four loads of ship are represented. As the conducted imitation design showed, the computer program formed the loads of ship, the feature of which there is their admission on the requirements of his landing, stability and general longitudinal durability. Minimization of forces of inertia at tossing of ship during transition is attained by the order of piling of containers in every tier: containers with greater mass are disposed nearer to the diametric plane of ship. In the imitation program is present module of estimation of parameters of landing, stability and longitudinal durability of the ship «Sky Gemini», using his hydrostatical tables and information about durability. Taking into account distributing of weight of containers of parties of loading, the criteria of nautical safety of ship, which are represented as the diagram of static stability, shire forces and bending moments, settle accounts by the program.

Optimum path planning of elliptic and cubic nanoparticles using one and dual probe atomic force microscopes

In this article, optimum path planning of elliptic and cubic nanoparticles by one and dual probe atomic force microscopes is investigated. Four different parameters are considered in the cost function, including area under critical time–force diagram, critical indentation depth, path smoothness and area under force–time diagram of primary impact of nanoparticles. Also three different obstacles are added to process to make it more real. The layout of obstacles are various in each geometry. Since surfaces are rough, the effects of roughness (surface and particle) are considered in process. Genetic algorithm method has been used for path planning.

Diagnosing Soft Tissue Sub-Surface Masses Using the XCS Classification System

Introduction: One of the most common types of cancer is breast cancer, which is considered as the second leading cause of death in women in Iran. Due to the fatality of this type of cancer, it is very important to diagnose the disease in the early stages and starting the treatment process. One of the methods to diagnose breast cancer is using mechanical arms (robot manipulator) to touch and measure the force in terms of displacement at the site of the breast touch by the robot. The hardness of the cancer tissue can affect the force diagram in terms of displacement, which can be used as a diagnostic method. The present study was performed to prepare a simulation model of breast soft tissue behavior considering subsurface masses. Then, a proposed classification system was designed to fit it.Material and Methods: In this section, first, the soft tissue behavior of the breast is simulated by considering sub-surface masses. The simulations are performed for a piece of tissue that is in the shape of a rectangular cube, as well as different dimensions of a spherical mass that is located at different depths and coordinates. Using simulation, various force-displacement diagrams have been obtained, based on which a data network.Results: The displacement force diagram for different modes is obtained using simulation. By giving the resulting diagrams to the trained system, the size and depth of the mass is determined. By comparing the obtained results with the initial model and the actual size and depth of the mass, a very good conformity is observed, which indicates the correct operation of the designed system and the performed simulation process.Conclusion: The proposed design system was used to diagnose the presence of tumors in tissue with sub-surface mass. The results show a high percentage of this method in diagnosis. However, the accuracy of this method can be greatly increased by increasing the amount of data given to the XCS system for training. On the other hand, instead of simulation data, test data on healthy and unhealthy people can be used for training.

Interpreting Inverse Magnetic Fabric in Miocene Dikes From Eastern Iceland

AbstractAnisotropy of Magnetic Susceptibility (AMS) is a valid tool to investigate magma flow direction within dikes. However, geometrically inverse magnetic fabric characterized by maximum magnetic susceptibility axis (kmax) perpendicular to the dike wall may complicate the interpretation of flow trajectories. To better understand the nature of this fabric, we present a multiscale study on 19 dikes (383 samples) in the Miocene Alftafjordur volcanic system (Iceland), where 80% of the samples show a geometrically inverse magnetic fabric. We carried out (1) AMS measurements at different magnetic fields and temperatures, along with Anisotropy of Anhysteretic Remanent Magnetization (AARM) analysis; (2) hysteresis loops and FORC diagrams; (3) thin section analysis; (4) structural fieldwork. A variable Ti‐content (0.1 < x < 0.6, Fe3‐xTixO4) titanomagnetite is the main magnetic carrier, and the contribution of the paramagnetic elongated crystals to the magnetic fabric is negligible. Single domain is not the prevailing domain state of the magnetic particles, suggesting that its occurrence cannot be the main cause for the inverse fabric. AMS analysis at different fields and temperatures along with AARM allow us to exclude any mineral phase change of the titanomagnetite across the dike. Nevertheless, kmax is parallel to a diffuse horizontal column‐like fracture pattern perpendicularly oriented with respect to the dike strike. This suggests that the Ti‐magnetite mineral orientation during dike cooling was affected by the fracture network progressively developing columnar basalts. This study demonstrates that the interpretation of AMS data on old and deep volcanic bodies is not straightforward and observations at different scales are required.

Dynamic Simulation of a Hydraulic Excavator to Determine the Joint Reaction Forces of Boom, Stick, Bucket, and Driving Forces of Hydraulic Cylinders

To optimize the dimensions of the boom, stick of the hydraulic excavator and select the suitable hydraulic bucket, stick, and boom cylinders, the designer must determine the joint reaction forces and driving forces. These forces always alter in an excavator's working cycle. They are conventionally calculated by mathematical method. This conventional method is complicated and challenging to determine the maximum reaction forces, which can break the stick and boom. This article builds a 3D model and simulates a working cycle of the hydraulic excavator to find the reaction force diagrams of boom and stick as well as driving forces of hydraulic cylinders by using computer software PTC Creo Parametric. Based on these results, the designer easily calculates the maximum tensions of the dimensions of boom and stick in a working cycle to optimize their dimensions as well as selects suitable hydraulic cylinders.

A Novel Strategy for the Fabrication of High-Performance Nanostructured Ce-Fe-B Magnetic Materials via Electron-Beam Exposure

Low magnetocrystalline anisotropy and energy product of the Ce 2 Fe 14 B compound severely restrict its application in permanent magnet applications, in spite of its potential as a novel permanent magnet alternative based on a widely abundant and inexpensive rare-earth (Cerium). A novel strategy combining melt-spinning and electron-beam exposure (EBE) aiming for fabricating high-performance Ce-Fe-B magnet is reported in this work. Remarkably, this strategy facilitates developing a suitable grain boundary configuration without using any additional heavy rare-earth element. Under the optimal EBE condition, the maximum energy product ( (BH) max ) of pure Ce-Fe-B alloy is 6.5 MGOe, about four times higher than that obtained after conventional rapid thermal process (RTP) method for the same precursor . This suggest that CeFeB materials using EBE could be a promising candidate after further processing, such as hot deforming or sintereing, to fill the performance “gap” between hexaferrite and Nd-Fe-B-based magnets. The enhanced intergranular magnetostatic coupling effect in EBE sample is further validated by mapping FORC diagrams. The in-situ observation of magnetic domain wall motion for Ce-Fe-B alloy using Lorentz transmission electron microscopy reveals that the boundary layers are very effective in pinning the motion of domain walls, leading to the increased coercivity under EBE. Micromagnetic simulations are also performed to verify the pinning effect of grain boundary configuration in the Ce-Fe-B system.

Beyond Recurring Free-Body Force Diagrams: Educational Pros and Cons of Alternative Means of Representing Forces and Interactions

Despite the fact that the free-body diagram is the most common method of representing forces in physics education, alternative means have been proposed over the years. Here we present a summary of the proposals found in the literature on physics education. We aim to discuss the pros and cons of these proposals, examine their degree of iconicity, and analyze their suitability for helping students understand the sum of forces (Newton’s second law), the action-reaction principle (Newton’s third law), and the nature of interaction (fundamental forces).

New Idea to Enhance Better Understanding of Free Body Diagrams in Solid Mechanics Course

Historically, majority of students taking solid mechanics course at my university find it confusing and even challenging to draw free body diagrams (FBDs) and to compute the internal forces correctly. Many instructors teach those topics in typical statics course and review the same principles in solid mechanics and design courses. However, many students either do not still fully understand the topic or have forgotten the concepts during the time gap between taking statics and the follow on courses. This is also true for colleges such as ours with mandatory co-op education in which students alternate between school and work terms. With incorrect calculation of internal loads (or load in each section of a member), the next steps of calculating the stress and deflection of members will go wrong. In a recent solid mechanics course taught by the author, 60 to 70 percent of the students could not correctly compute the internal forces within each section of an axially loaded member. Although majority of students drew the free body diagram of the entire system correctly, only a few could realize or interpret the correct values of forces within each section of a member. Others drew incorrect FBDs that do not satisfy static equilibrium.The author came up with an idea (alternative approach or method) to teach free body diagrams that partially address the above-mentioned difficulties that many students face. Similar to axial loading, students find it difficult to determine the internal loads for torsional members. Determining the internal loads for beams subjected to complex loading is even more confusing and challenging to these students. Although the new method proposed in this paper is not fully assessed for its effectiveness, it was used during the Fall 2018 (September to December) and Winter 2019 (January to March) solid mechanics classes. The total number of students was around 50 in both academic terms. The students viewed this new method as one of the potential approaches to understand the equilibrium concepts. Same course will be taught by the author during Spring 2019 term to assess the effectiveness of the proposed method 'before and after' by giving the same problems to students using the old approach and to students using the new approach. Preliminary assessment results based on the students' performance on in-class, homework, quizzes and exams will be available by the end of Winter 2019 term. Active learning activities are being used to help teach the method. It is hoped that this alternative method will be an effective approach for instructors teaching statics and solid mechanics courses to make the struggling students better understand the concepts of static equilibrium. Details of this approach will be discussed in detail in this paper along with several numerical examples.