Determination of unknown parameters in impervious layers by inverse method

2008 ◽  
Vol 123 (5) ◽  
pp. 3614-3614
Author(s):  
Eva Escuder Silla ◽  
Jesús Alba Fernandez ◽  
Jaime Ramis Soriano ◽  
Romina Del Rey Tormos
Keyword(s):  
Inverse Method ◽  
Unknown Parameters

An inverse method for determination of the interdiffusivity in aluminide coatings formed on superalloy

2004 ◽  
Vol 182 (1) ◽  
pp. 112-116 ◽  
Author(s):  
Hua Wei ◽  
Xiaofeng Sun ◽  
Qi Zheng ◽  
Guichen Hou ◽  
Hengrong Guan ◽  
...  
Keyword(s):  
Inverse Method ◽  
Aluminide Coatings

scholarly journals Investigation of a Stochastic Inverse Method to Estimate an External Force: Applications to a Wave-Structure Interaction

2012 ◽  
Vol 2012 ◽  
pp. 1-25 ◽  
Author(s):  
S. L. Han ◽  
Takeshi Kinoshita
Keyword(s):  
External Force ◽  
Inverse Method ◽  
Inverse Function ◽  
Wave Structure ◽  
Dynamic Responses ◽  
Structure Interaction ◽  
External Forces ◽  
Interaction Problem ◽  
Wave Structure Interaction

The determination of an external force is a very important task for the purpose of control, monitoring, and analysis of damages on structural system. This paper studies a stochastic inverse method that can be used for determining external forces acting on a nonlinear vibrating system. For the purpose of estimation, a stochastic inverse function is formulated to link an unknown external force to an observable quantity. The external force is then estimated from measurements of dynamic responses through the formulated stochastic inverse model. The applicability of the proposed method was verified with numerical examples and laboratory tests concerning the wave-structure interaction problem. The results showed that the proposed method is reliable to estimate the external force acting on a nonlinear system.

Validation of an Inverse Method for the Source Determination of a Hazardous Airborne Material Released from a Point Source in an Urban Environment

2017 ◽  
pp. 329-332 ◽  
Author(s):  
George C. Efthimiou ◽  
Spyros Andronopoulos ◽  
Ivan V. Kovalets ◽  
Alexandros Venetsanos ◽  
Christos D. Argyropoulos ◽  
...  
Keyword(s):  
Point Source ◽  
Urban Environment ◽  
Inverse Method ◽  
Source Determination

Determination of Thermal Parameters of a Work-Roll in Warm Rolling Using Inverse Modeling

2018 ◽  
Author(s):  
Vinod Yadav
Keyword(s):  
Inverse Method ◽  
Work Roll ◽  
Rolling Process ◽  
Thermal Parameters ◽  
Shop Floor ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Convective Heat Transfer Coefficients ◽  
Work Rolls

Thermal parameters of a work-roll play an important role in the modeling of the rolling process, due to periodic thermal loading. The knowledge of thermal parameters is also vital in understanding the fatigue life of the work-roll and the thermal crown. However, estimation of the thermal parameters viz., thermal conductivity, thermal diffusivity and convective heat transfer coefficients at both, inner and outer roll periphery is tough to realize during the rolling process. Various methods employed earlier for measuring the thermal properties of work-rolls in the rolling process requires intrusion in the surface of the work-rolls, mainly to embed the thermocouples inside the rolls. These methods are easy to implement, but it is really hard to achieve truthful estimation. A possible way out is to measure the average thermal parameters of a work roll in the rolling process by utilizing the measured temperature at two specified locations on the work-roll surface. In this work, an inverse method is proposed to estimate the thermal properties and convective heat transfer coefficients of a roll in the rolling process. The inverse method makes use of a direct model of temperature determination considering plane strain problem, which is based on the integral transform method. For minimizing the error between the computed and experimentally recorded data, a quasi-Newton method is used. In lieu of shop floor experiments, a finite element method (FEM) based package ABAQUS 6.10 is used to obtain the temperature distribution in the work-roll. Further, an additive white Gaussian error is added in the FEM simulated measurements to assess the inverse method for stability towards mild measurements. The inverse estimation is successfully validated and can be used in shop floor for the online determination of thermal parameters of the work-rolls in the rolling process.

Computational mechanical property determination of viscoelastic/plastic materials from nanoindentation creep test data

2009 ◽  
Vol 24 (3) ◽  
pp. 1245-1257 ◽  
Author(s):  
Jianjun Wang ◽  
Timothy C. Ovaert
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Finite Element ◽  
Test Data ◽  
Plastic Material ◽  
Test Method ◽  
Element Formulation ◽  
Unknown Parameters ◽  
Plastic Materials

Nanoindentation is a widely accepted test method for materials characterization. On account of the complexity of contact deformation behavior, design of parametric constitutive models and determination of the unknown parameters is challenging. To address the need for identification of mechanical properties of viscoelastic/plastic materials from nanoindentation data, a combined numerical finite element/optimization-based indentation modeling tool was developed, fully self-contained, and capable of running on a PC as a stand-alone executable program. The approach uses inverse engineering and formulates the material characterization task as an optimization problem. The model development consists of finite element formulation, viscoelastic/plastic material models, heuristic estimation to obtain initial solution boundaries, and a gradient-based optimization algorithm for fast convergence to extract mechanical properties from the test data. A four-parameter viscoelastic/plastic model is presented, then a simplified three-parameter model with more rapid convergence. The end result is a versatile tool for indentation simulation and mechanical property analysis.

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