![]() Omit theįrequency-spectra pairs are entered rather than period-spectra pairs.ĭata is part of input, immediately following 1 = print beginning 54 values and last 54.Print the time history that is generated. Will be used to perfect the computed time history. NF equally spaced frequencies by interpolation.ĭefault is the greater of 35 or the number of points in the input spectrum. History generated with the prior seed value)" but Value when you want to produce a "different (from the time Time history will be produced for each seed value. Used as a unique random number generation "seed." A unique This value must beĪ positive integer (in the range of 1 to 2,147,483,647) to be This value mustīe greater than zero and greater than f12Įnding time of the acceleration decay. This valueĮnding time of the steady acceleration. This value must be greater than f14 (T3).Ġ.05) associated with the input spectrum.Įnding time of the acceleration rise time. time (in seconds) in the generated time history. With the spectrum time history load Variable or Command Starting on the next line, enter Spectra in the following Spectrum-spec = SPECTRUM ( TMAX f9) ( DTI f10) ( DAMP f11) ( T1 f12) ( T2 f13) ( T3 f14) ( SEED f15) OPTIONS NF f16 NITR f17 ( THPRINT f18 ) ( SPRINT f19 ) ( FREQ ) Enter f12,į13, and f14 to indicate the rise, steady, & decay Time history based on the following specifications. The program will automatically calculate the acceleration The spectrum-spec option can be used to specifyĪ synthetic ground motion acceleration time history based statistically on a MDAMP is specified, then modal damping isĭEFINE DAMPING INFORMATION command, which must be ![]() TR.26.2 Specifying Constants for Members and Specify a value of exactly 0.0000011 to ignore damping.ĬDAMP is specified, then composite damping is usedĪs determined by the values for material damping (and spring damping, if More subdivisions or smaller step size will make the digitizedįorce curve more closely match a sine wave. It is not the DT used to integrate for the Used to subdivide a ¼ cycle into this manyĭigitize the forcing function. With function time history load Variable or CommandįREQUENCY, then cyclic frequency (cycles / Load types are used to create the load vector needed for each time step of theĪnalysis for information on input specification forĪpplication of the forcing function and/or ground motion loads. The arrival times and the time-force pairs for the TR.32.10.2 Time Varying Load for Response HistoryĪnalysis). Pairs will be added to get the times for a particular set of joints in the TIME The arrival times and the times from the time-force The same load type may have different arrival timesįor different joints and hence all those values must be specified here. Arrival time is the time at whichĪ load type begins to act at a joint (forcing function) or at the base of the (seconds) of the various dynamic load types. Values of the various possible arrival times Nonzero force, there will be a sudden application of that force over a single If the first point is not at zero time, then theįorces before the first time (but after the arrival time) will be determined byĮxtrapolation using the first two points entered. (current force unit) or acceleration (current length unit/sec 2)ĭepending on whether the time varying load is a forcing function or a ground Values of time (in sec.) and corresponding force FRC file contains the history of the 12 endįorces of every member of the structure at every time step, and the 6 reactions History of the displacements of every node. The save option results in the creation of two Primarily used to convert acceleration in g’s to current units This number should be sequential.Īll forces, accelerations, and amplitudes entered, read or generated within Step-by-step integration of the uncoupled equations. Explicitly defined time history load Variable or Command
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