The analysis is performed using the commercial available software ansys. The resulting plot can then be used to pick off the response of any linear system, given its natural frequency of oscillation. Oct 31, 2016 download seismic analysis and design of structures using response spectra or time history motions by ed wilson professor emeritus of civil engineering university of california, berkeley february 24, 2010. For the free online simulation course from cornell university, ansys student 2019 r3 is recommended. After each spectrum analysis, you can use rappnd to write the results to an rst file. Ansys response spectrum analysis tutorial pdf best of all, they are entirely free to find, use and download, so there is no cost or stress at all. Oct 17, 20 for response spectrum analysis you need to fulfill one requirement. Theory of response spectrum analysis new mexico tech. Apply a force in single point response spectrum analysis using ansys workbench mechanical. The equivalence is restricted to a single mode of vibration.
Drop a response spectrum system onto the solution cell of the modal system. Response spectrum analysis of building frame ansys student. The maximum modal responses are determined from the base excitation response spectrum. Response spectrum analysis rsa isnt like doing a simple static fe analysis, it is actually quite involved, and can require a lot of interpretation. Ansys program may also be called from anseismic if apdl file is available. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the. I would like to do frequency response analysis of a nonlinear system. Response spectrum results in ansys response spectrum results in ansys shakenbake444 mechanical op. The psd response graph is shown below graph variables enter reference number 4 ok example 6. The accelerograph records three orthogonal components of ground acceleration. Methodology the design lateral shear force at each floor in each mode is computed by staad in accordance with the is. Response spectra can also be used in assessing the response of linear systems with multiple modes of oscillation multidegree of freedom systems, although they are only accurate for low levels of damping.
Modeling and analysis of prestressed concrete u section girder bridge. Base reactions for responsespectrum analysis technical. The seismic records are loaded from peer and earthquake analysis files are produced in ansys parametric design language apdl. Mar 11, 2017 a response spectrum analysis calculates the maximum response of a structure to transient loads such as displacement,velocity or acceleration, that are forced into vibration by a base vibration or shock. Modified response spectrum analysis to compute shear force. Response spectrum analysis perform the following operations. What is difference between time history analysis and.
Summary of presentation on advanced numerical modeling and analytical techniques. Dynamic analysis using response spectrum seismic loading before the existence of inexpensive personal computers, the response spectrum method was the standard approach for linear seismic analysis 15. Ansys mechanical workbench supports response spectrum analysis. Theoretical basis for response spectrum calculations in spectral analysis understand that the method of determining response spectrum sasat for a given diagram of accelerations ft, where t refers to period, sa refers to acceleration spectrum, t refers to time, while ft is a. Ansys student is used by hundreds of thousands of students globally. Two point weights of 10 lbf each are attached at midpoint and end point of the beam.
The response spectrum method of analysis is developed using the following steps. Singlepoint response spectrum a single response spectrum excites all specified points in the model. Why are responsespectrum base reactions different from the sum of individual reactions. Responsespectrum base reactions will not match the sum of individual joint reactions because their formulations differ. The full mechanical apdl interface also supports the. Nuclear power plant buildings and components, for seismic loading airborne electronic equipment for shock loading commercial buildings in earthquake zones types of response spectrum analysis. Mechanical enterprise can cover all of your needs for dynamic analysis, including for linear dynamics modal, harmonic, spectrum response and random. Apply a force in single point response spectrum analysis using.
The first data reported from an earthquake record is generally the peak ground acceleration pga which expresses the tip of the maximum spike of the acceleration ground motion figure 1. Depending on the results requested in analysis settings for a response spectrum solution, velocity and acceleration results can be obtained, in addition to deflection, stress and strain. The total response is then derived by srss for each modal response. Ansys response spectrum analysis tutorial pdf download. Modified response spectrum analysis to compute shear force in. Earthquake analyses in ansys workbench free download as word. How to apply a force in single point response spectrum. Response spectrum analysis civil engineering community. A responsespectrum analysis calculates the maximum response of a structure to transient loads such as displacement,velocity or acceleration, that are forced into vibration by a base vibration or shock. Xansys view topic xansys single point response spectrum. Pdf spectrum analysis with ansys apdl researchgate.
Introduction to structural dynamics and earthquake engineering module 9 response spectrum modal analysis prof. Equivalent lateral force for an earthquake is defined as a set of lateral force which will produce the same peak response as that obtained by dynamic analysis of structures. What is difference between time history analysis and response. Response spectrum analysis provides insight into dynamic behavior by measuring pseudospectral acceleration, velocity, or displacement as a function of structural period for a given time history and level of damping. Analysis procedure response spectrum analysis solidworks.
To overcome the difficulty of performing multipoint response spectrum analysis for engineering structures under spatially varying. Seismic analysis for a 12m antenna structure single point response spectrum sprs analysis in ansys figures courtesy of vertex antennentechnik gmbh your contact person. You will be glad to know that right now ansys response spectrum analysis tutorial pdf is available on our online library. In a response spectrum analysis, the results of a modal analysis are used in terms of a known spectrum to calculate displacements and stresses in the model. Anseismic seismic analysis of structures with ansys and. It is a great choice if your professor is already using it for your course or if you are already familiar with the ansys workbench platform. Try restructuring your deck so that you have only modal analysis solv save fini response spectrum analysis solv save fini dont forget to include the correct modal expansion and rs options e. It is practical to envelope response spectra such that a smooth curve represents the peak response for each realization of. Acceleration maximum response computationally efficient time history analysis can be nonlinear requires time vs. Xansys view topic xansys shock response spectrum analysis. Ansys apdl commands objects after response spectrum analysis.
If you have an input of this kind quite common for most earthquake type analysis than you should be able to perform eigen valueeigen vector derivation followed by response spectrum analysis. The student community is a public forum for authorized ansys academic product users to share ideas and ask questions. Finally, you can use a load case combination to srss the results from the two response spectrum analysis to calculate the combined result for the full modal range. Johnson department of earth and environmental science, new mexico tech 1.
Take the time to talk to someone about this, do some background reading read the ansys manual i think youll find its excellent if you take the time to go through it, and then run a simple. Nov 16, 2015 the seismic records are loaded from peer and earthquake analysis files are produced in ansys parametric design language apdl. The earthquake ground acceleration in each direction is given as a digitized response spectrum curve of pseudo spectral acceleration response versus period of the structure. As harmonic response in for linear system, i am doing the transient response analysis now.
Shock response spectrum analysis approach for optimal design of. Single point response spectrum sprs analysis in ansys. Response spectrum analysis is linear while contact is nonlinear. Summary of presentation on advanced numerical modeling and. Since one is the inverse of the other, the two graphs are just mirrored when plotting on a logarithmic scale. How can i do a response spectrum analysis using more than. Responsespectrum analysis is a lineardynamic statistical analysis method which measures the contribution from each natural mode of vibration to indicate the likely maximum seismic response of an. Structural safety analysis based on seismic service conditions for.
Response spectrum analysis with ansys workbench youtube. This tutorialcourse is created by sseacademy perform thermal and structural analysis on 3d models with ansys. A response spectrum is a plot of the peak or steadystate response displacement, velocity or acceleration of a series of oscillators of varying natural frequency, that are forced into motion by the same base vibration or shock. Jan 30, 2018 the interface of ansys workbench mechanical enables the input of base excitation at all supports in a single point response spectrum analysis. The study approach is applicable for packaging design of wide range of electronic. Table 2 summarizes representative modal analysis results obtained from the 2 and 3layered model. A comparative analysis on absolute and srss methods of response spectrum using staadpro written by a. Ansys workbench with the boundary conditions applied to the modal analysis.
I wanted to do a response spectrum analysis of a building frame. Ansys mechanical enterprise is the flagship mechanical engineering software solution that uses finite element analysis fea for structural analysis using the ansys mechanical interface. Nov 03, 2004 which is not the standard way of doing this type of analysis in ansys. A comparative analysis on absolute and srss methods of. Response spectrum analysis can be used to estimate the peak response displacement, stress, etc. Base reactions are calculated for each mode before modes are combined using the cqc or srss modalcombination rule. Two modified response spectrum analysis mrsa methods to compute design shear forces in tall rc shear wall buildings, together with a novel method to compute strain to predict locations of yielding of vertical reinforcement and possible crushing of concrete in rc walls and columns are proposed in this study. Is there any way to convert the transient response output. The earthquake ground acceleration in each direction is given as a digitized responsespectrum curve of pseudo spectral acceleration response versus period. Number of modes used in the response spectrum analysis has to cover that the missing mass is less than 10% of the total system mass. Responsespectrum analysis seeks the likely maximum response to these equations rather than the full time history. The method is only approximate, but it is often a useful, inexpensive method for preliminary design studies.
It covers an enormous range of applications and comes complete with everything you need from geometry preparation to optimization and all the steps in between. This toolbox is suitable for carrying dynamic response spectrum analysis drsa for a given structure, as well as producing linear elastic response spectra and elastoplastic response spectra, using elasticideally plastic forcedeformation relation. Anyone who modeled a structure in ansys can use the analysis files produced with anseismic by just calling them. Seismic analysis response spectrum analysis linear requires frequency vs.
What is response spectrum structural dynamics civil. In this case ansys treats contact elements as linear in their initial state e. Ansys response spectrum analysis tutorial pdf ansys response spectrum analysis tutorial pdf are you looking for ebook ansys response spectrum analysis tutorial pdf. You can use the file command to toggle between the two spectrum rst files within post1. Get the maximum response of each modal of the structure under a given excitation with specific frequency. Originally, when we were studying the dynamics of a simple single degree of freedom structure, we noticed that given one type of earthquake, we dont have to keep solving the equat. Modal analysis is performed to identify the modes, and the response in that mode can be picked from the response spectrum. Response spectrum analysis is a lineardynamic statistical analysis method which measures the contribution from each natural mode of vibration to indicate the likely maximum seismic response of an. Preethi published on 20180730 download full article with reference data and citations. For response spectrum analysis you need to fulfill one requirement. Two modified response spectrum analysis mrsa methods to compute design shear forces in tall rc shear wall buildings, together with a novel method to compute strain to predict locations of yielding of vertical reinforcement and possible crushing of concrete. Presentation on response spectrum analysis as per indian code. Seismic analysis and design of structures using response. Responsespectrum analysis provides insight into dynamic behavior by measuring pseudospectral acceleration, velocity, or displacement as a function of.
The interface of ansys workbench mechanical enables the input of base excitation at all supports in a single point response spectrum analysis. Analysis procedure response spectrum analysis the normal modes are calculated first to decouple the equations of motion with the use of generalized modal coordinates. Earthquake analyses in ansys workbench normal mode spectral. Theoretical basis for response spectrum calculations in spectral analysis understand that the method of determining response spectrum sasat for a given diagram of accelerations ft, where t refers to period, sa refers to acceleration spectrum, t refers to time, while ft is a given time analysis function. Download seismic analysis and design of structures using response spectra or time history motions by ed wilson professor emeritus of civil engineering university of california, berkeley february 24, 2010. Introduction the basis of engineering seismology is the need to quantify how a given structure will respond to. Dec 11, 2012 response spectrum analysis seeks the likely maximum response to these equations rather than the full time history.
Sep 10, 20 equivalent lateral force for an earthquake is defined as a set of lateral force which will produce the same peak response as that obtained by dynamic analysis of structures. Modal and response spectrum analyses of an iter divertor. Response spectrum method of analysis with simplified. Details title what is response spectrum structural dynamics duration 12 mins language english format mp4 size 19 mb download method direct download. Seismic analysis single point response spectrum analysis of.
Either singlepoint or multipoint response spectrum analysis can be performed. Introduction the most direct description of an earthquake motion in time domain is provided by accelerograms that are recorded by instruments called strong motion accelerographs. Design response spectra are often provided in terms of the period, rather than the frequency. For each mode, a response is read from a design spectrum based on the modal frequency and a given damping ratio.
How can i do a response spectrum analysis using more than 10,000 modes. The design response spectrum is the actual input to the response spectrum analysis. The full mechanical apdl interface also supports the input of a force in such an analysis. Set the displacement in the z direction to zero to make a look a like 2d analysis. This is done i believe using modal superpositioning in ansys. Apply a force in single point response spectrum analysis.
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