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I am trying to some simulation of cantilever beam bending in abaqus.

Magdalena dj

I set the deflection at the free-end as the boundary condition, and try to solve the reaction force perpendicular to the beam longitudinal axis. But I get in trouble to calculate the total reaction force at the free-end. I know abaqus can do some operations on existing output data. I tried to sum the reaction forces of all nodes in the free-end plane, but the result did not agree with the Timoshenko beam equation.

At first check if you are properly recovering the total reaction force: just load the beam model at the end using a vertical force instead of using a prescribed deflection and recover the total reaction. A Coupling Constraint couples the motion of a surface to the motion of a single point, which is the reference point.

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Clamp the reference point. The reaction is all concentrated at the reference point. Are you sure that you have a sufficiently refined mesh; i. Also note that Timoshenko beam theory is for thick beams, but that doesn't mean you can use it to solve a solid section e.

How can I get contact force in abaqus?

So check your problem parameters and make sure you are satisfying tenoshenko beam theory assumptions to a reasonable extent. Skip to main content. Search form Search. Secondary menu recent posts user list about contact Main menu research education mechanician opinion software industry conference job video. Create new account Request new password.

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Dear all, This is my first post in iMechanica forum. If anyone can give some suggestions, that would be great.

abaqus reaction force

Thanks in advance. Ping Du. Free Tags:. Permalink Submitted by Wieslaw Beres on Sun, There could be hundreds of reasons why you are not getting the correct answer. I have the same problem,do you understand what to do? Are you sure that you have Permalink Submitted by Akumar on Sat, Output variables are available for: element integration points, element section points, whole elements, and element sets.

The following sections discuss the input file syntax for requesting output to the data and results files. Element output, nodal output, contact surface output, energy output, fastener interaction output, modal output, and section output are available. Element output, nodal output, contact surface output, energy output, modal output, and section output are available.

A results file output request can appear only once per step but remains in effect in subsequent steps unless it is redefined. You can convert the selected results file job-name. The data are always written at the start and end of each step in which a results file output request is active. The times at which the results are written are referred to as time marks. The specified number of intervals must be a positive integer.

Find Reaction forces for a Beam

By default, results will be written at the increment ending immediately after each time mark. Alternatively, you can choose to have the time increment size adjusted so that an increment will end exactly at each of the time marks calculated by dividing the step into n equal intervals. You can output element variables stresses, strains, section forces, element energies, etc.

The output requests can be repeated as often as necessary within a step to define output for different types of element variables, different element sets, etc. The same element or element set can appear in several output requests. In general, element output requests remain in effect for subsequent steps unless they are redefined; the appearance of a single element output request in a step removes all element output requests from a previous step.

For first-order heat transfer elements the integration points are located at the corners of the element in heat capacitance calculations. Individual variables such as a particular stress component cannot be selected and must be obtained by postprocessing.

You can specify the element set for which output is being requested. You can request output for a particular rebar. If you do not specify the name of a rebar, output will be given for all rebars in the specified element set or in the whole model, if you have not specified an element set. In shell, membrane, and surface elements rebar output is available at the integration points and at the element's centroid.

By default, output is provided at the integration points. By default, the variables are output at the integration points where they are calculated. You can choose to output the variables at the centroid of each element the centroid of the reference surface of a shell element or the midpoint between the end nodes of a beam element.

Centroidal values are obtained by interpolation of the integration point values if the integration scheme for the element does not include a centroidal integration point. You can choose to extrapolate the variables to the nodes, then average them over all of the elements in the set that contribute to each node.

The partitioning is based upon the structure of the elements: element type, number of section points, type of material, single layer or composite, etc. Partitioning is not based upon the values of element properties such as thicknessmaterial orientations, or material constants. Averaging will occur only over elements that contribute to a node and belong to the same averaging region.

In some situations you may want the averaging regions to take into account the values of element properties. For example, since variables may be discontinuous between elements with different material constants, you may not want elements with different property definitions included in the same averaging region. You can choose to extrapolate the element integration point variables to the nodes of each element independently, without averaging the results from adjoining elements.

The shape functions of the element are used for purposes of extrapolation and interpolation of output variables. Extrapolated values are generally not as accurate as the values calculated at the integration points in the areas of high stress gradients, particularly in the case of modified triangles and tetrahedra.A linear constraint equation is defined in Abaqus by specifying:. Either node sets or individual nodes can be specified as input. If node sets are used, corresponding set entries will be matched to each other.

If sorted node sets are given as input, you must ensure that the nodes are numbered such that they will match up with each other correctly once sorted.

The nodes in an unsorted node set will be used in the order that they are given in defining the set see Node definition. If the first entry is a single node, subsequent entries must be single nodes. If the first entry is a node set, subsequent entries can be either node sets or single nodes. The latter option is useful if a degree of freedom at each of a set of nodes depends on a degree of freedom of a single node, such as may occur in certain symmetry conditions or in the simulation of a rigid body.

The nodes must be specified as sets. The first set can contain one or more points. Subsequent sets must contain only a single point. In addition, the coefficient A 1 should not be set to zero. If a local coordinate system Transformed coordinate systems is defined for any node involved in the equation, the variables at that node appear in the equation in the local system.

abaqus reaction force

If an equation constraint is defined at the part or part instance level, the nodal variables are transformed initially according to the positioning data given for each instance of the part see Assembly definition.

This is easily done by rewriting the equation as.

Extracting Reaction force from Field output

Linear constraint equations introduce constraint forces at all degrees of freedom appearing in the equations. These forces are considered external, but they are not included in reaction force output. Therefore, the totals provided at the end of the reaction force output tables may reflect an incomplete measure of global equilibrium. To illustrate this behavior, consider a spring-supported beam subjected to a concentrated load as shown in Figure 1.

These reaction forces produce a global force balance in the Y-direction, but since the constraint forces are not included in reaction force output, the global moment balance about point A cannot be verified. The global force balance can also be incomplete.

abaqus reaction force

The constraint forces at the pulley, F x and F yare not included in the reaction force output, producing incomplete global force balances in both the X - and Y -directions. The linear constraint generates constraint forces at all the degrees of freedom involved in the equation. For a given constraint equation these forces are proportional to their respective coefficients.

To find the constraint forces, introduce a node Z that is not attached to any element in the model; rewrite the constraint equation as. The reaction force obtained at node Z will be equal to the constraint force acting at node P in degree of freedom i. For example, if the equation is. Since the coefficient of u 3 5 is the opposite of the coefficient of u 3the constraint force at node 5 is the same as the reaction force at node Since the coefficient of u 3 6 is the same as the coefficient of u 3the constraint force at node 6 is the opposite of the reaction force at node The equation can be rewritten as.

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Prior to time t 0 which is assumed to be at the end of a stepdegree of freedom m of node Z is left unrestrained. Defining a linear constraint equation A linear constraint equation is defined in Abaqus by specifying: the number of terms in the equation, N ; the nodes, Pand the degrees of freedom, icorresponding to the nodal variables u i P ; and the coefficients, A n.

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Use with transformed coordinate systems If a local coordinate system Transformed coordinate systems is defined for any node involved in the equation, the variables at that node appear in the equation in the local system. Use within a part If an equation constraint is defined at the part or part instance level, the nodal variables are transformed initially according to the positioning data given for each instance of the part see Assembly definition.

Constraint forces and global equilibrium Linear constraint equations introduce constraint forces at all degrees of freedom appearing in the equations.

Figure 1. Beam with no linear constraints.Log In. Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action. Click Here to join Eng-Tips and talk with other members! Already a Member? Join your peers on the Internet's largest technical engineering professional community. It's easy to join and it's free. Register now while it's still free! Already a member? Close this window and log in.

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Join Us! By joining you are opting in to receive e-mail. Promoting, selling, recruiting, coursework and thesis posting is forbidden. Students Click Here. Related Projects. Hi, I am working on large I-girder steel structure with different openings in its web, I have attached four springs on four corners of the structure when looking from front.

I need to verify the forces in the spring, for stiffness I used 1, I also dont know about its exact units, as maual calls it N per relative displacement. How can I see magnitude of the force in springs. See section Regarding the units, what unit system did you use to build your model? How did you define the spring stiffness? If you have used SI units metres, Newtons, seconds.

Hi, I don't konow if I understand exactly the geometry but I think you can just look at the RF reaction forces at one of the spring extreme that is fixed if it is.

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For further information, including about cookie settings, please read our Cookie Policy. By continuing to use this site, you consent to the use of cookies. We value your privacy. Asked 2nd Feb, Mohammed Al-Fasih. How can I get contact force in abaqus? Mechanical Behavior of Materials. Computational Mechanics. Structural Analysis.

Most recent answer. Anahita Khooban. Amirkabir University of Technology. If you need the exactly force between 2 surfaces that you defined interaction between them. All Answers Shahram A. TED Universitesi. Universiti Tun Hussein Onn Malaysia. Hamed Saghafi. Hi, you can easily find the acceleration of impactor. Zhong Chen. Ford Motor Company.

Or, you can go mechanical analysis-whole surface quantities such as CFN total force due to contact pressureetc. Ali Al-Rifaie.

How to get Nodal point force?

Al Muthanna University.Log In. Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action.

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Related Projects. Hello everyone, I am running a load controlled spherical ball contact on a plate. I am using an axisymmetric model of the plate and axisymmetric analytical rigid ball.

I have a RP reference point at the center of the ball where I am applying a small displacement at first to establish contact and then load after removing the initial displacement. The analysis is running till completion but I want to extract Reaction Force at RP, which is always 0!

Obviously that is not possible.

abaqus reaction force

What am I doing wrong? Thank you for your help! Check the reaction force at the restraint as that will be equal to the reaction force of the RP. What do you mean by "at the restraint"? The reaction force at the RP is 0 and also at the contact point i. Thank you so much! The RF at the restraint is exactly equal to the applied load.

I am happy now :. The reaction force at the contact point is also 0, which was throwing me off. I guess if I want to calculate the reaction force at the contact, I have to calculate the contact stresses and work it out from there. It is probably treating it as internal nodes and not showing any RF. Red Flag This Post Please let us know here why this post is inappropriate.Log In. Thank you for helping keep Eng-Tips Forums free from inappropriate posts.

The Eng-Tips staff will check this out and take appropriate action. Click Here to join Eng-Tips and talk with other members! Already a Member? Join your peers on the Internet's largest technical engineering professional community.

It's easy to join and it's free. Register now while it's still free! Already a member? Close this window and log in. Are you an Engineering professional? Join Eng-Tips Forums! Join Us! By joining you are opting in to receive e-mail. Promoting, selling, recruiting, coursework and thesis posting is forbidden. Students Click Here. Related Projects. Hi everybody! I've got a problem in calculating the reaction forces in Abaqus. I created a set based on the geometry that consist of this surface, to have the possibility of examine the results and plot them on a graph.

When I check the results, the program shows me the value of the reaction forces in every node that lie on the surface, but I'm not able to calculate the global force, resultant of all the forces that the constraint exerts on the surface. How I can calculate the resultant? Because the surface is cylindrical, I can't use the "view cut" tool. I attached a photo of the geometry of the system I'm studying.

Hey I would suggest the history output feature. In its domain field, hover down to Set and select the set whose resultant you want to see. Assign the type of results you want for that node. In here, select the type of result of nodes whose resultant you want to observe. Finally, click on Save As and select Sum out of the options given.