How to Perform Time-History Analysis?

October 21, 2021
BLOG NEWS & TRENDS

Introduction of Functions for Time-History Analysis in midas Gen

 

Process in midas Gen

 

 

time history analysis Process in midas Gen

time-history analysis

Time history analysis has a procedure similar to Pushover analysis.  After running the analysis, the member force, hinge status, and story drift results should be checked.

 
 
 
 
 
TABLE OF CONTENTS
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 

Member Type for Time History & Definition of Hinge


 

 

3For member type, unlike pushover analysis, the point spring and masonry are not provided.

 

 

 

Hinge Models

 

4

 

- Kinematic Hardening Hysteresis Model

 

Kinematic Hardening hysteresis model

- Origin-Oriented Type Hysteresis Model

 

Origin-oriented type hysteresis model

- Clough Type Hysteresis Model

 

Clough type hysteresis model

- Takeda Type Hysteresis Model

 

Takeda type hysteresis model

- Normal Bilinear Type Hysteresis Model

 

Normal Bilinear Type hysteresis model

 

- Slip Bilinear Type hysteresis model

 

Slip Bilinear Type hysteresis model

 

 

 

 

 

Hinge Model – Fiber Model


A structural model that includes nonlinearity in a distributed fashion, using finite fiber elements, is able to characterize in higher detail the reinforced concrete elements and is thought to capture more accurately response effects on such elements.

 

hinge model-fiber model- Section Division for Fiber Model Definition

It supports generating a Mesh shape and arranging rebar automatically.

fiber division of section dialog box- Inelastic Material Properties (Stress-Strain Curve)

 

Concrete > Kent & Park Model

 

Inelastic Material PropertiesRebar > Menegotto-Pinto Model

 

Inelastic Material Properties

- Fiber Cell Result Plotting

 

analysis result of fiber section dialog box

 

 

 

 

Define Time-History Load


In order to define Time History Load, the Analysis Method, Initial Load Consideration, and Damping Method should be selected as shown below.

 

 

define time history load

 

 

 

 

 

Result of Time-History Loads


It provides Hinge Status, Member Force/Deformation, and Energy Graph.

 

- Hinge Status

hinge status

- Member Force/Deformation

 

Member Force andDeformation

- Energy Result

 

Energy Result

 

 

 

 

 

Analysis Results (Graph & Text Output)


Gen supports to check the results of deformation, velocity, and acceleration by time at specific node or hinges in graph and text report.

 

- Result Curve : Force-Deformation Curve for Each Members

 

Result Curve

 

- Result Curve: Time(sec)-Deformation Curve

 

Result Curve

 

 

 

 

 

Load Combinations for Time-History


Gen is supporting to convenient function for checking the results of member force and deformation.
Maximum and average values for multiple selected ground waves are provided in the result table.

 

create load combinations dialog box

- Beam force table for Max. result

 

13- Beam force table for an average result

 

14

 

Consider Time History results in the design by inputting the load combinations.

 

load combinations dialog box

 

 

 

 

 

Analysis Time


As test result, In the case of the model with 4000-analsys steps, about 5000 elements and 4000 hinges, it took about 7 minutes. And, in the case of the model with 3000 analysis steps, about 1500 elements and 6000 hinges, it took about 5 minutes. Recently, the analysis speed has been improved by 2 times.

 

analysis time

 

 

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Young-il Seo
Young-il Seo | Principal Structural Engineer

Young-il has over 13+ years of experience in building design, especially high-rise buildings with column reduction analysis, plant structures, pushover analysis, health monitoring, and vibration control projects. Since 2016, he is planning and providing technical supports for midas building products such as midas Gen, nGen, and Design+.

E-BOOK Fundamentals of
Time-History Analysis

This material provides basic concepts of time-history analysis by performing
in midas Gen. It is helpful to analyze regarding simple building, machine vibration,
floor vibration, and seismic control devices.