scholarly journals Harmonic-Modal Hybrid Reduced Order Model for the Efficient Integration of Non-Linear Soil Dynamics

2020 ◽  
Vol 10 (19) ◽  
pp. 6778 ◽  
Author(s):  
Claudia Germoso ◽  
Jean Louis Duval ◽  
Francisco Chinesta
Keyword(s):  
Site Response ◽  
Laboratory Data ◽  
Nonlinear Behavior ◽  
Forced Response ◽  
Equivalent Linearization ◽  
Response Analysis ◽  
Damping Factor ◽  
Alternative Analysis ◽  
Soil Response ◽  
Non Linear

Nonlinear behavior of soils during a seismic event has a predominant role in current site response analysis. Soil response analysis, and more concretely laboratory data, indicate that the stress-strain relationship of soils is nonlinear and exhibits hysteresis. An equivalent linearization method, in which non-linear characteristics of shear modulus and damping factor of soils are modeled as equivalent linear relations of the shear strain is usually applied, but this assumption, however, may lead to a conservative approach of the seismic design. In this paper, we propose an alternative analysis formulation, able to address forced response simulation of soils exhibiting their characteristic nonlinear behavior. The proposed approach combines ingredients of modal and harmonic analyses enabling efficient time-integration of nonlinear soil behaviors based on the offline construction of a dynamic response parametric solution by using Proper Generalized Decomposition (PGD)-based model order reduction technique.

Comparison Study of One-Dimensional Site Response Analysis Methods

2016 ◽  
Vol 32 (2) ◽  
pp. 1075-1095 ◽  
Author(s):  
Chi-Chin Tsai ◽  
Chun-Way Chen
Keyword(s):  
Amplification Factor ◽  
Site Response ◽  
Nonlinear Behavior ◽  
Response Analysis ◽  
Comparison Study ◽  
Soil Response ◽  
One Dimensional ◽  
Site Factor ◽  
Nonlinear Properties ◽  
Numerical Approaches

The ground responses computed via frequency domain (FD) equivalent linear (EQL) and time domain (TD) nonlinear (NL) methods can considerably differ because of the constitutional differences in numerical approaches, damping formulations, and modeling of nonlinear soil response. To systematically evaluate the TD-NL and FD-EQL approaches, this study performs TD-NL, TD-EQL, and FD-EQL site response analyses considering different input motions, intensities of input motions, depths of soil columns, and nonlinear properties. Results show that the differences in the site responses calculated by the two approaches are highly influenced by dynamic soil properties, the significant nonlinearities of which (e.g., sand) tend to magnify such differences and the high damping of which tend to mitigate the differences. An amplification factor by TD-NL exhibits more nonlinearity than that by FD-EQL but agrees well with the nonlinearity in the 2015 NEHRP site factor, indicating that TD-NL is a better method than FD-EQL for modeling soil nonlinear behavior.

scholarly journals Seismic hazard on West Bandung district using non-linear earthquake response analysis

2021 ◽  
Vol 331 ◽  
pp. 07003
Author(s):  
Anggun Mayang Sari ◽  
Afnindar Fakhrurrozi ◽  
Arifan Jaya Syahbana ◽  
Dwi Sarah ◽  
Bambang Setiadi ◽  
...  
Keyword(s):  
Scientific Information ◽  
Earthquake Ground Motion ◽  
Response Analysis ◽  
Building Structures ◽  
Tourist Attractions ◽  
Soil Response ◽  
Non Linear ◽  
The Government ◽  
Retail Company ◽  
Earthquake Response Analysis

West Bandung District is one of the government areas that grow rapidly in West Java. Here several infrastructures such as Highspeed Rail Development, Modern Residences, Tourist Attractions Area, and International Retail Company supply major contributions to economic development. Rapid construction in Bandung Basin caused the government to pay attention to risk factors, especially building structures. One of the natural hazards that must be considered is the presence of an active Lembang fault. Therefore, there is a need for a study that takes into account how the earthquake waves damaged the buildings. In this study, an analysis of the soil dynamics due to earthquake ground motion from bedrock was carried out. The analysis is carried out using the wave propagation method, which is a non-linear analysis of the soil response. The research was conducted at 12 points locations in West Bandung District. As the result, the location with the highest PGA surface value is in the Mekar Jaya area, while the lowest risk is found in the Cililin area. Furthermore, this study provides scientific information on seismic hazards to support government disaster risk reduction programs.

An Efficient Response Analysis Method for a Non-Linear/Parameter Changing System Using Sub-Structure Modes

1993 ◽  
Vol 207 (1) ◽  
pp. 41-52
Author(s):  
H K Kim ◽  
Y-S Park
Keyword(s):  
Equations Of Motion ◽  
Forced Response ◽  
Suggested Method ◽  
Response Analysis ◽  
Synthesis Methods ◽  
Lumped Mass ◽  
State Equations ◽  
Mass Model ◽  
Non Linear ◽  
Forced Responses

An efficient state-space method is presented to determine time domain forced responses of a structure using the Lagrange multiplier based sub-structure technique. Compared with the conventional mode synthesis methods, the suggested method can be particularly effective for the forced response analysis of a structure subjected to parameter changes with time, such as a missile launch system, and/or having localized non-linearities, because this method does not need to construct the governing equations of the combined whole structure. Both the loaded interface free-free modes and free interface modes can be employed as the modal bases of each sub-structure. The sub-structure equations of motion are derived using Lagrange multipliers and recurrence discrete-time state equations based upon the concept of the state transition matrix are formulated for transient response analysis. The suggested method is tested with two example structures, a simple lumped mass model with a non-linear joint and an abruptly parameter changing structure. The test results show that the suggested method is very accurate and efficient in calculating forced responses and in comparing it with the direct numerical integration method.

Response Analysis of Secondary Systems With Nonlinear Supports

1991 ◽  
Vol 113 (4) ◽  
pp. 524-531 ◽  
Author(s):  
T. Igusa ◽  
R. Sinha
Keyword(s):  
Random Vibration ◽  
Natural Frequencies ◽  
Hysteresis Loops ◽  
Nonlinear Behavior ◽  
Equivalent Linearization ◽  
Response Analysis ◽  
Analysis Method ◽  
Secondary System ◽  
Secondary Systems ◽  
Insight Into

This paper introduces a simplified random vibrations analysis method of linear secondary systems with nonlinear supports. The method separates, as much as possible, the nonlinear analysis of the supports from the linear analysis of the remainder of the secondary system. Equivalent linearization is used to generate response-dependent linear properties of the supports directly from hysteresis loops. These properties are then combined with the properties of the secondary system, and a response analysis is performed using mode combination. The analysis procedure is simpler than standard random vibration methods, and for narrow-band responses, it accurately models nonlinear behavior. In addition, the procedure uses equivalent modal quantities, such as natural frequencies and damping ratios, which provide insight into the effects of the nonlinear supports on the secondary system.

Conceptual Analysis of the Non-Linear Forced Response of Aerodynamically Unstable Bladed-Discs

2013 ◽  
Author(s):  
Roque Corral ◽  
Juan Manuel Gallardo ◽  
Rahul Ivaturi
Keyword(s):  
Time Domain ◽  
Linear Response ◽  
Harmonic Excitation ◽  
Friction Model ◽  
Forced Response ◽  
Response Analysis ◽  
Non Linear ◽  
Aerodynamic Instability ◽  
Time Domain Response ◽  
The Time Domain

The response of aerodynamically unstable tuned bladed-discs with non-linear friction dissipation at blade-root attachments due to harmonic external excitation is studied. The bladed-disc is modeled using a simple mass-spring system and the effect of friction is modeled using a micro-slip friction model. The response is computed in time domain using a Runge-Kutta scheme. The time domain response is decomposed to obtain the evolution of traveling waves in the bladed-disc. Parametric studies have been conducted to study the non-linear response at different vibration amplitudes at high and low engine orders of excitation. It is seen that the non-linearity due to friction gives rise to a complicated interaction between the synchronous response of the system due to harmonic excitation and the non-synchronous response of the system due to aerodynamic instability. For low excitation levels the system behaves as in the pure flutter regime where a single, or at most a few, aerodynamically unstable modes may be found in the final state when a limit cycle is reached. When the forcing is large enough the aerodynamic instability is suppressed and only the non-linear response of the excited mode may be seen. It is concluded that the superimposition of the flutter and forced response analysis in terms of vibration amplitude is not valid and leads to prediction of vibration amplitudes significantly larger than that obtained when both phenomena are simulated together.

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