Conjugate Gradient Back Analysis of Mechanical Parameters of Box Structure Based on Layered Shell Element

For the composite glass box girder, the generalized Bayesian objective function of elastic constants of the structure was derived based on layered shell element theory. Mechanical performances of the composite glass box girder were solved by layered shell element method. Combined with quadratic parabolic interpolation search scheme of optimized step length, the adaptive Powell’s optimization theory was taken to complete the stochastic identification of elastic constants of composite glass box girder. Then the adaptive Powell’s identification steps of elastic constants of the structure were presented in detail and the adaptive Powell’s identification procedure was accomplished. From some classic examples, it is finally achieved that the adaptive Powell’s identification of elastic constants of composite glass box girder has perfect convergence and numerical stability, which testifies that the adaptive Powell’s identification theory of elastic constants of composite glass box girder is correct and reliable. The stochastic characteristics of systematic responses and elastic constants are well deliberated in generalized Bayesian objective function. And in iterative processes, the adaptive Powell’s identification is irrelevant with the complicated partial differentiation of the systematic responses from the layered shell element model to the elastic constants, which proves high computation efficiency.

Download Full-text

Layered-Shell Element Method of Calculating the Multi-Ribbed Composite Slab’s Elastic Lateral Stiffness

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.1346 ◽

2011 ◽

Vol 243-249 ◽

pp. 1346-1350

Author(s):

Peng Chang ◽

Yao Luo

Keyword(s):

Elastic Modulus ◽

Influence Factor ◽

Shell Element ◽

Lateral Stiffness ◽

Layered Shell ◽

Element Analysis ◽

Factors Affecting ◽

Modeling Process ◽

The Finite Element Analysis ◽

Element Method

A new method for calculating the elastic lateral stiffness of the multi-ribbed composite slab by ANSYS—the layered-shell element method is introduced in this paper. In the modeling process, there are two ways for establishing the model using element SOLID46: the first refers to regarding the slab as a whole to make arranged layers. While the second type suggests that making arranged layers in each part already separated according to the materials. Especially when there are reasonable hypothesis, the analysis results can guarantee certain precision. By comparison among the two models and the experimental results, no errors with each other have exceeded 5%. The whole model is used for the numerical simulation in view of its briefness. Several factors affecting elastic lateral stiffness are considered, mainly including elastic modulus of the concrete, elastic modulus of the brick, and number of the ribbed-column. From the calculating results, conclusion can be deduced that all of these factors affecting the slab’s stiffness significantly. Along with the factors’ rising, the elastic lateral stiffness of the wall grows up. Basically, the influence factor and the elastic lateral stiffness of the slab present to be linear relationship. It is also meaningful to see that the elastic modulus of the brick plays a very important part in the elastic lateral stiffness of the wall. When compared to the SOLID65 and LINK8 used for the slab’s modeling before, the layered-shell element method is simple in principle, and distinct in conception. Above all, because only one type of element in the finite element analysis is used, it will cost less time when used on building a model of integrated architectural construction.

Download Full-text

The Mechanical Parameters of a Rock Slope Displacement Back Analysis Based on the Orthogonal Test Design

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.256-259.207 ◽

2012 ◽

Vol 256-259 ◽

pp. 207-210

Author(s):

Chun Lai Qu ◽

Ke Jiang ◽

Min Xue ◽

Zhao Cai Zhang

Keyword(s):

Three Dimensional ◽

Back Analysis ◽

Orthogonal Test ◽

Mechanical Parameters ◽

The Neural Network ◽

Measurement Results ◽

Orthogonal Test Design ◽

Slope Treatment ◽

Slope Displacement ◽

The Relationship

The mechanics parameters of a slope are difficult to determine accurately by conventional methods, because of weathering, fracture and excavation induced stress release. Based on the orthogonal test and three-dimensional numerical calculation to get the learning samples of displacement, By using the neural network method to obtain the relationship between the mechanical parameters and displacement, Combined with measurement results of deformation in the field mining, Obtained the reasonable strata parameters to provide the basis for slope treatment.

Download Full-text

Stochastic Filtering Back Analysis of Elastic Modulus of Box Shaped Beam

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1096.557 ◽

2015 ◽

Vol 1096 ◽

pp. 557-561

Author(s):

Bo Yu ◽

Tao Hong ◽

Jian Zhang

Keyword(s):

Elastic Modulus ◽

Analytical Procedure ◽

Back Analysis ◽

Shell Element ◽

Mechanical Analysis ◽

Displacement Function ◽

Shaped Beam ◽

Stochastic Filtering ◽

Practical Engineering ◽

Element Theory

With the development of civil engineering, the box shaped beam has been widely applied in practical engineering. In general, it is composed of concrete and steel and compared with mechanical analysis, little research has been carried on the back analysis of elastic modulus of box shaped beam. With degraded solid element theory, the shell element is deduced and the displacement function is obtained. The necessary observation revision equation and Kalman regenerative matrix are derived. The stochastic filtering back analysis steps of elastic modulus of the box shaped beam are presented and the analytical procedure is compiled. Through analysis of a classic example, some important conclusions about stochastic filtering back analysis of elastic modulus of box shaped beam are obtained.

Download Full-text

Study of Back Analysis of Material Parameters of Mass Concrete

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.52-54.768 ◽

2011 ◽

Vol 52-54 ◽

pp. 768-772

Author(s):

Wen Gai Lan ◽

Xin Ming Zhao

Keyword(s):

Kalman Filtering ◽

Back Analysis ◽

Mass Concrete ◽

Mechanical Parameters ◽

Coupling Problem ◽

Filtering Theory ◽

Filtering Method ◽

Material Parameters ◽

Research Fields ◽

First Time

The Kalman filtering theory was applied for the back analysis of mechanical parameters of mass concrete on the first time. The time-spreading equation and the observation-correcting equation were deduced. After the coupling problem of extending Kalman filtering theory and FEM was solved, the Kalman-FEM formula were deduced and the corresponding back analysis procedures were given. The results indicate that the Kalman filtering method has good characteristics of convergence and stability. The broached method can be used in other research fields such as the back analysis of creeping parameters. Many more conclusions are tested and discussed through a classic example.

Download Full-text