scholarly journals Parameter identification of the elastic modulus of ground rock based on blasting using the first order adjoint method

2008 ◽  
Author(s):  
T. Ishimoto ◽  
M. Kawahara
Keyword(s):  
Elastic Modulus ◽  
Parameter Identification ◽  
Adjoint Method ◽  
First Order

Parameter Identification of Elastic Modulus of Rock Based on Blasting Waves in Tunnel Excavation

2011 ◽  
Vol 403-408 ◽  
pp. 75-79
Author(s):  
Yuto Motoyama ◽  
Mutsuto Kawahara
Keyword(s):  
Elastic Modulus ◽  
Parameter Identification ◽  
Elastic Moduli ◽  
Adjoint Equation ◽  
Measured Data ◽  
Blasting Vibration ◽  
Tunnel Excavation ◽  
First Order ◽  
Identification Method ◽  
Identification Technique

The objective of this research is to present an identification method for elastic moduli of ground rock, through the first-order adjoint equation method using the measurements of the blasting vibration in tunnel excavation. Parameter identification is a minimization problem of the square sum of discrepancy between the computed and observed velocities. For the identification of these parameters, the magnitudes of the blasting force should be identified beforehand. In this study, propagation of an elastic wave is assumed because the amplitude of such a wave is infinitesimal. After the identification of the blasting force, the elastic moduli of three layers are identified simultaneously. We assume that the damping of vibration is linear. By applying the identification technique at the Ohyorogi tunnel site, we verify that the method is useful for tunnel excavation. Using measured data from actual tunnel excavation sites, the numerical identification method presented in this paper is shown to be useful for practical tunnel excavation.

First-order adjoint method: nonlinear dynamics

2009 ◽  
pp. 401-421
Author(s):  
John M. Lewis ◽  
S. Lakshmivarahan ◽  
Sudarshan Dhall
Keyword(s):  
Nonlinear Dynamics ◽  
Adjoint Method ◽  
First Order

Probabilistic Analysis on the Uncertainty in Natural Frequency of Functionally Graded Material Beams

2019 ◽  
Vol 889 ◽  
pp. 484-488
Author(s):  
Van Thuan Nguyen ◽  
Duy Liem Nguyen
Keyword(s):  
Elastic Modulus ◽  
Natural Frequency ◽  
Functionally Graded Material ◽  
Functionally Graded ◽  
Order Perturbation ◽  
First Order ◽  
Graded Material ◽  
Natural Frequency Analysis ◽  
Mcs Method ◽  
First Order Perturbation

This paper applies the stochastic finite element method (SFEM) to perform the natural frequency analysis of functionally graded material (FGM). It is assumed that the elastic modulus and width of the FGM beam vary along the thickness and width directions following exponential functions. The stochastic eigenvalue problem is solved independently by first-order perturbation and Monte Carlo simulation (MCS) method through changing elastic modulus as spatial randomness. The results show that the first-order perturbation method based SFEM produces a very close value to MCS method.

Incremental Formulation of Concrete Creep under Stress History

2017 ◽  
Vol 865 ◽  
pp. 313-319
Author(s):  
Si Hyung Park ◽  
Yeong Seong Park ◽  
Ta Lee ◽  
Yong Hak Lee
Keyword(s):  
Elastic Modulus ◽  
Constitutive Equation ◽  
Drying Shrinkage ◽  
Concrete Specimen ◽  
Creep Model ◽  
Beam Specimen ◽  
First Order ◽  
Age Dependent ◽  
Incremental Formulation ◽  
Basic Equations

An incremental format of the age-dependent constitutive equation was derived by expanding the total form of the constitutive equation by using the first-order Taylor series to describe the persistent change in the creep-causing stress state as well as drying shrinkage and the development of the elastic modulus. The resulting incremental constitutive equation was defined by three basic equations for basic creep, drying shrinkage, and the development of the elastic modulus. Three types of laboratory experiments were carried out to validate the performance of the presented age-dependent constitutive equation; these included cylindrical concrete specimen tests with and without axial reinforcements and reinforced beam specimen tests. The performance of the creep model was compared with those calculated by the other age-dependent constitutive equations.

scholarly journals PARAMETER IDENTIFICATION VIA THE ADJOINT METHOD: APPLICATION TO PROTEIN REGULATORY NETWORKS

2006 ◽  
Vol 39 (2) ◽  
pp. 475-482 ◽  
Author(s):  
Robin L. Raffard ◽  
Keith Amonlirdviman ◽  
Jeffrey D. Axelrod ◽  
Claire J. Tomlin
Keyword(s):  
Parameter Identification ◽  
Regulatory Networks ◽  
Adjoint Method

scholarly journals Adjoint accuracy for the full Stokes ice flow model: limits to the transmission of basal friction variability to the surface

2014 ◽  
Vol 8 (2) ◽  
pp. 721-741 ◽  
Author(s):  
N. Martin ◽  
J. Monnier
Keyword(s):  
Friction Coefficient ◽  
Parameter Identification ◽  
Adjoint Method ◽  
Synthetic Data ◽  
Adjoint Problem ◽  
Second Order ◽  
The Self ◽  
Algorithmic Differentiation ◽  
Numerical Assessment ◽  
Linear Friction

Abstract. This work focuses on the numerical assessment of the accuracy of an adjoint-based gradient in the perspective of variational data assimilation and parameter identification in glaciology. Using noisy synthetic data, we quantify the ability to identify the friction coefficient for such methods with a non-linear friction law. The exact adjoint problem is solved, based on second-order numerical schemes, and a comparison with the so-called "self-adjoint" approximation, neglecting the viscosity dependence on the velocity (leading to an incorrect gradient), common in glaciology, is carried out. For data with a noise of 1%, a lower bound of identifiable wavelengths of 10 ice thicknesses in the friction coefficient is established, when using the exact adjoint method, while the "self-adjoint" method is limited, even for lower noise, to a minimum of 20 ice thickness wavelengths. The second-order exact gradient method therefore provides robustness and reliability for the parameter identification process. In another respect, the derivation of the adjoint model using algorithmic differentiation leads to the formulation of a generalization of the "self-adjoint" approximation towards an incomplete adjoint method, adjustable in precision and computational burden.

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