Bayesian Estimation of Cumulative Damage From Seismic Response Records of Buildings

2001 ◽  
Author(s):  
Ernesto Heredia-Zavoni ◽  
Antonio Zeballos ◽  
Roberto Montes-Iturrizaga ◽  
Luis Esteva
Keyword(s):  
Mechanical Properties ◽  
Probability Distributions ◽  
Damage Function ◽  
Cumulative Damage ◽  
Degree Of Freedom ◽  
Inelastic Behavior ◽  
Concrete Frames ◽  
Inelastic Response ◽  
Bayesian Formulation ◽  
Secant Stiffness

Abstract This paper discusses the estimation of probability distributions of damage using response records from instrumented buildings subjected to seismic excitations. The objective of the paper is to show how the information on the evolution of the mechanical properties of a system can be used to assess the state of cumulative damage. This implies expressing damage on the structural members in terms of its influence on the residual mechanical properties of the system. The information on the inelastic behavior from response records is used in a bayesian formulation along with a damage function to update prior probability distributions of damage. The damage function models the hysteretic cycles of inelastic response in terms of an initial damage and of the displacement amplitudes of the response cycles. It describes the evolution of the secant stiffness through the cycles of inelastic response as a function of cumulative damage and displacement amplitudes. The updating of probability distributions of damage for single degree of freedom systems is presented first. Extensions to the case of non-linear multi-degree of freedom systems are discussed next. Examples of reinforced concrete frames are given for illustrative purposes.

Behavior of Congruent Tessellation Stacks Under Torsional Loading

2016 ◽  
Author(s):  
Yves Klett ◽  
Fabian Muhs ◽  
Peter Middendorf
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Degree Of Freedom ◽  
Simple Solution ◽  
Torsional Loading ◽  
Element Analysis ◽  
Torsional Loads ◽  
Structural Mechanisms ◽  
Potential Use

The combination of several layers of rigidly foldable tessellations into can produce cellular material stacks with interesting properties, especially if the resulting stack preserves the mobility of its constituting layers. To achieve this, the construction of functional joining and hinging concepts need to be developed. This paper presents a simple solution to effectively joining different 1-DOF (degree of freedom) tessellation layers. The mechanical properties of the resulting structures under torsional loads are evaluated using finite element analysis, and their potential use as structural mechanisms is discussed.

The Research on Hysteretic Energy in the Equivalent System Schemes between Multi Degree of Freedom System and Single Degree of Freedom System

2012 ◽  
Vol 166-169 ◽  
pp. 2177-2181
Author(s):  
Ming Qiang Sheng ◽  
Ying Liu
Keyword(s):  
Seismic Design ◽  
Seismic Waves ◽  
Good Alternative ◽  
Cumulative Damage ◽  
Degree Of Freedom ◽  
Equivalent System ◽  
Single Degree Of Freedom ◽  
Hysteretic Energy ◽  
Single Degree ◽  
Comparison And Analysis

The cumulative damage produced by severe earthquake is significant to the structural dilapidation and collapse. Most design methods based on force or displacement can’t reflect the effect of cumulative damage. Energy-based seismic design is known as a good alternative design. At present the research on the hysteretic energy of single-degree of freedom system(SDOF) is abundant, but real buildings can only be simplified as multi-degree of freedom systems(MDOF) mostly. Therefore how to acquire suitable equivalent single-degree of freedom system(ESDOF) is a key program. In this paper 12 equivalent system schemes(ESS) have been put forward, then the ratio of hysteretic energy(RH) of 6-floors framework was calculated with 30 typical seismic waves. Based on the comparison and analysis between calculations of 3 typical ESS, by the way of envelope fitting, the expression of RH related to earthquake characteristic value a/v was established.

scholarly journals Degradation and erosion mechanisms of bioresorbable porous acellular vascular grafts: an in vitro investigation

2017 ◽  
Vol 14 (132) ◽  
pp. 20170102 ◽  
Author(s):  
Piyusha S. Gade ◽  
Keewon Lee ◽  
Blaise N. Pfaff ◽  
Yadong Wang ◽  
Anne M. Robertson
Keyword(s):  
Mechanical Properties ◽  
Mass Loss ◽  
Mechanistic Model ◽  
Vascular Grafts ◽  
Damage Function ◽  
Surface Erosion ◽  
Outer Diameter ◽  
In Vitro Investigation

A fundamental mechanism of in situ tissue regeneration from biodegradable synthetic acellular vascular grafts is the effective interplay between graft degradation, erosion and the production of extracellular matrix. In order to understand this crucial process of graft erosion and degradation, we conducted an in vitro investigation of grafts ( n = 4 at days 1, 4, 7, 10 each) exposed to enzymatic degradation. Herein, we provide constitutive relationships for mass loss and mechanical properties based on much-needed experimental data. Furthermore, we formulate a mathematical model to provide a physics-based framework for understanding graft erosion. A novel finding is that despite their porous nature, grafts lost mass exponentially via surface erosion demonstrating a 20% reduction in outer diameter and no significant change in apparent density. A diffusion based, concentration gradient-driven mechanistic model of mass loss through surface erosion was introduced which can be extended to an in vivo setting through the use of two degradation parameters. Furthermore, notably, mechanical properties of degrading grafts did not scale with mass loss. Thus, we introduced a damage function scaling a neo-Hookean model to describe mechanical properties of the degrading graft; a refinement to existing mass-dependent growth and remodelling (G&R) models. This framework can be used to improve accuracy of well-established G&R theories in biomechanics; tools that predict evolving structure–function relationships of neotissues and guide graft design.

scholarly journals Effect of degeneration on the six degree of freedom mechanical properties of human lumbar spine segments

2016 ◽  
Vol 34 (8) ◽  
pp. 1399-1409 ◽  
Author(s):  
Dhara B. Amin ◽  
Dana Sommerfeld ◽  
Isaac M. Lawless ◽  
Richard M. Stanley ◽  
Boyin Ding ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lumbar Spine ◽  
Degree Of Freedom ◽  
Human Lumbar Spine ◽  
Six Degree Of Freedom

The Relationship Between Microstructure and Mechanical Properties of Late 19th/Early 20th Century Wrought Iron Using the Generalized Method of Cells Model

2002 ◽  
Vol 712 ◽  
Author(s):  
Jennifer J. Hooper ◽  
Lori Graham ◽  
Tim Foecke ◽  
Timothy P. Weihs
Keyword(s):  
Mechanical Properties ◽  
20Th Century ◽  
Mechanical Response ◽  
Early 20Th Century ◽  
Inelastic Behavior ◽  
Silicate Slag ◽  
Wrought Iron ◽  
Generalized Method Of Cells ◽  
The Relationship

ABSTRACTThe discovery of the RMS Titanic has led to a number of scientific studies, one of which addresses the role that the structural materials played in the sinking of the ship. Chemical, microstructural, and mechanical analysis of the hull steel suggests that it was state-of-the-art for 1912 with adequate fracture toughness for the application. However, the quality of the wrought iron rivets may have been an important factor in the opening of the steel plates during flooding. Preliminary studies of Titanic wrought iron rivets revealed an orthotropic, inhomogeneous composite material composed of glassy iron silicate (slag) particles embedded in a ferrite matrix. To date, very little is understood about the properties of wrought iron from that period. Therefore, in order to assess the quality of the Titanic material, contemporary wrought iron was obtained from additional late 19th/early 20th century buildings, bridges, and ships for comparison. Image analysis completed on the Titanic wrought iron microstructure showed a high slag content that is very coarse and unevenly distributed. To investigate how microstructure impacts the mechanical properties, and hence the quality of late 19th/early 20th century wrought iron, a detailed analysis of the relationship between the microstructural features and the mechanical behavior was completed. Here we present the first step in that process: the use of the Generalized Method of Cells (GMC) to predict the mechanical response of composites with variable microstructural properties. The GMC tool is used to generate the effective inelastic behavior of the composite from the individual constituent properties.

Development of Seated Human Model With Uncertain Parameters and Estimation of the Ride Comfort

2018 ◽  
Author(s):  
Jong-Jin Bae ◽  
Namcheol Kang
Keyword(s):  
Ride Comfort ◽  
Probability Distributions ◽  
Equations Of Motion ◽  
Degree Of Freedom ◽  
Human Model ◽  
Whole Body ◽  
Mode Shapes ◽  
Comfort Index ◽  
Parametric Studies ◽  
Nonlinear Equations Of Motion

This study deals with the biodynamic responses of the 5-degree-of-freedom mathematical human model to whole-body vibrations in a vehicle. The nonlinear equations of motion of the human model were derived, and the spring constants and damping coefficients were extracted from the experimental data in the literature using optimization process. The natural frequencies and mode shapes were also calculated using linearized human model. In order to examine the effects of the variations of the human parameters, the parametric studies with respect to the stiffness values were performed. The mode veering phenomenon was observed between fourth and fifth mode of the linearized human model. In addition, the frequency responses of the nonlinear 5-degree-of-freedom model were also obtained, and the frequency shift and jump phenomena were observed. Furthermore, the estimation of the ride comfort was performed using CarSim and Matlab/Simulink with several road profiles according to ISO classification. Besides, we also calculated the ride comfort index using BS 6841 standard. In order to calculate the statistical responses of human model, the Monte-Carlo simulation applied to the nonlinear human model having uncertain stiffness assuming Gaussian distribution. These stochastic approaches enable the proposed human model to estimate probability distributions of the ride comfort index.

Experimental Studies on the Buckling Under Axial Compression of Integrally Stringer-Stiffened Circular Cylindrical Shells

1977 ◽  
Vol 44 (4) ◽  
pp. 721-730 ◽  
Author(s):  
T. Weller ◽  
J. Singer
Keyword(s):  
Mechanical Properties ◽  
Linear Theory ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
Experimental Studies ◽  
Inelastic Behavior ◽  
Shell Material ◽  
Stiffened Shells ◽  
Circular Cylindrical Shells ◽  
Shell Geometry

An experimental study of the buckling of closely spaced integrally stringer-stiffened circular cylindrical shells under axial compression was carried out to determine the influence of stiffener and shell geometry, as well as mechanical properties of shell material, on the applicability of linear theory. Tests included 84 shells made of two different kinds of steel with completely different mechanical properties and 74 shells made of 7075-T6 Aluminum alloy. Agreement between linear theory and experiments was found to be governed primarily by shell geometry, Z, where for Z > 1000 values of “linearity” (ratio of experimental buckling load to the predicted one) of 70 percent and considerably above were obtained. Correlation with linear theory was also found to be affected by stringer area parameter (A1/bh) where for (A1/bh) > 0.45 the values of linearity obtained exceeded 65 percent and usually were much higher. No significant effect of other stiffener and shell parameters on the applicability of linear theory could be discerned for the specimens tested. The boundary conditions were found to be of importance and for some steel shells the inelastic behavior of the shell material was found to have a considerable effect on the linearity. Predictions of imperfection sensitivity studies could not be correlated with test results. By a conservative structural efficiency criterion all the tested stringer-stiffened shells were found to be more efficient than equivalent weight isotropic shells.

Inelastic Seismic Test of the Small Bore Piping and Support System: Part 3 — Simulation Analysis for the Piping Seismic Test

2008 ◽  
Author(s):  
Eiji Shirai ◽  
Kazutoshi Eto ◽  
Akira Umemoto ◽  
Toshiaki Yoshii ◽  
Masami Kondo ◽  
...  
Keyword(s):  
Support System ◽  
Simulation Analysis ◽  
Local Strain ◽  
System Model ◽  
System Response ◽  
Piping System ◽  
Inelastic Behavior ◽  
Inelastic Response ◽  
Strain Behavior ◽  
Safety Margins

Seismic safety is one of the major key issues of nuclear power plant safety in Japan. It is demonstrated that nuclear piping possesses large safety margins through the small bore piping and support system test, consisted of three dimensional piping, supports, U-bolts, and concrete anchorages, using the E-defense vibration table of National Research Institute for Earth Science and Disaster Prevention, Hyogo Earthquake Engineering Research Center at Miki city, by the extremely higher seismic excitation level [1, 2]. A simulation analysis for the piping system is described with a focus on the inelastic behavior of the support to the whole piping system response, and the subsequent interaction when both piping and support shows inelastic behavior. The analysis for the inelastic response of the piping seismic test was conducted using the FEM program ABAQUS. It requires a large amount of time to carry out a strain behavior analysis of the localized piping element and also calculate the dynamic inelastic response of the whole piping system, simultaneously. Therefore the following two steps analysis method is proposed. (Step 1) Seismic response analysis of the piping system. (Step 2) Evaluation for local strain of elbows. The simplified piping system model is adopted to solve the non-linear dynamic response both of the supports and elbows of the piping system in (Step 1). On the other hand, the piping system model with partially detailed elbow shell elements is applied to evaluate local strain behavior of the elbow in (Step 2).

Damage Function for the Mechanical Properties of Steels

1977 ◽  
Vol 36 (3) ◽  
pp. 336-346 ◽  
Author(s):  
A. Alberman ◽  
J. P. Genthon ◽  
L. Salon ◽  
G. Allegraud
Keyword(s):  
Mechanical Properties ◽  
Damage Function
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