scholarly journals Traffic Capacity Assessment of the Urban Elevated Bridge after Near-Field Explosion Based on the Response Surface Method

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jinghui Jiang ◽  
Chaoyi Xia ◽  
Kunpeng Wang ◽  
He Xia ◽  
Qikai Sun
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Response Surface ◽  
Structural Damage ◽  
Near Field ◽  
Assessment Method ◽  
Surface Model ◽  
Traffic Capacity ◽  
Elevated Bridge

The traffic capacity of the urban elevated bridge is assessed after it is attacked by a near-field explosion, using the residual bearing capacity of the damaged pier as the assessment index. First, the finite element model of a reinforced concrete slab under near-field explosion is established by ANSYS/LS-DYNA software and compared with the experimental results, which verifies the effectiveness of the ALE (arbitrary Lagrangian–Eulerian) algorithm and the accuracy of the mesh size and material properties. Then, an “explosive-air-pier” coupling analysis model is constructed using the finite element method, and the damage of the reinforced concrete pier under three types of car bombs is evaluated. Furthermore, a response surface model for the residual bearing capacity of the pier is utilized to calculate the failure probabilities of various damage levels of the pier under the three types of car bombs and to assess the traffic capacity of the bridge after near-field explosion. The established assessment method can be used to predict the probability of bridge structural damage at various levels under different types of car bombs and to provide a reference for exploring a probability-based safety assessment method of post-explosion bridges.

Optimization Design of Pressure Shell in Underwater Vehicle Based on Response Surface Model

2009 ◽  
Vol 419-420 ◽  
pp. 89-92
Author(s):  
Zhuo Yi Yang ◽  
Yong Jie Pang ◽  
Zai Bai Qin
Keyword(s):  
Finite Element ◽  
Response Surface ◽  
Optimization Design ◽  
Engineering Application ◽  
Element Model ◽  
Response Surface Model ◽  
Design Stage ◽  
Surface Model ◽  
Design Variables ◽  
Structure Strength

Cylinder shell stiffened by rings is used commonly in submersibles, and structure strength should be verified in the initial design stage considering the thickness of the shell, the number of rings, the shape of ring section and so on. Based on the statistical techniques, a strategy for optimization design of pressure hull is proposed in this paper. Its central idea is that: firstly the design variables are chosen by referring criterion for structure strength, then the samples for analysis are created in the design space; secondly finite element models corresponding to the samples are built and analyzed; thirdly the approximations of these analysis are constructed using these samples and responses obtained by finite element model; finally optimization design result is obtained using response surface model. The result shows that this method that can improve the efficiency and achieve optimal intention has valuable reference information for engineering application.

scholarly journals Damage Assessment of Reinforced Concrete Structures: A Review

2022 ◽  
pp. 1-7
Author(s):  
Gomasa Ramesh ◽  
Keyword(s):  
Reinforced Concrete ◽  
Damage Assessment ◽  
Structural Damage ◽  
Concrete Structures ◽  
Practical Method ◽  
Assessment Method ◽  
Reinforced Concrete Structures ◽  
Current Response ◽  
Damage Indices ◽  
Seismic Damage Assessment

Damage may be assessed using several damage indices with values associated with different structural damage states. The usefulness of a variety of current response-based damage indices in seismic damage assessment is addressed and critically assessed. A novel rational damage assessment method is provided, which measures the structure’s physical reaction characteristics. A practical method based on various analyses is given to evaluate the damaged structures in earthquakes of different intensities. This paper provides an overview of previous research works on the damage assessment of the reinforced concrete structures. This study may be helpful for easy understanding about the damage assessment of reinforced concrete structures and reduce the impacts of disaster and surrounding structures.

scholarly journals Multiobjective Optimization of Precision Forging Process Parameters Based on Response Surface Method

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Fayuan Zhu ◽  
Zhaohui Wang ◽  
Mi Lv
Keyword(s):  
Finite Element ◽  
Service Life ◽  
Multiobjective Optimization ◽  
Response Surface ◽  
Process Parameters ◽  
Optimization Method ◽  
Surface Model ◽  
Forming Quality ◽  
Hollow Shaft ◽  
Precision Forging

In order to control the precision forging forming quality and improve the service life of die, a multiobjective optimization method for process parameters design was presented by applying Latin hypercube design method and response surface model approach. Meanwhile the deformation homogeneity and material damage of forging parts were proposed for evaluating the forming quality. The forming load of die was proposed for evaluating the service life of die. Then as a case of study, the radial precision forging for a hollow shaft with variable cross section and wall thickness was carried out. The 3D rigid-plastic finite element (FE) model of the hollow shaft radial precision forging was established. The multiobjective optimization forecast model was established by adopting finite element results and response surface methodology. Nondominated sorting genetic algorithm-II (NSGA-II) was adopted to obtain the Pareto-optimal solutions. A compromise solution was selected from the Pareto solutions by using the mapping method. In the finite element study on the forming quality of forging parts and the service life of dies by multiobjective optimization process parameters, the feasibility of the multiobjective optimization method presented by this work was verified.

Damage Assessment of Subway Station Columns Subjected to Blast Loadings

2018 ◽  
Vol 18 (03) ◽  
pp. 1850034 ◽  
Author(s):  
Q. S. Yan
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Damage Assessment ◽  
Terrorist Attack ◽  
Near Field ◽  
Subway Station ◽  
Reinforced Concrete Column ◽  
Key Factor ◽  
Subway Stations ◽  
Blast Loadings

With the increasing threat of terrorism attack, the probability of explosion inside the subway is very large. Reinforced concrete columns are the main supporting members of subway stations. If the columns of a subway station were subjected to near-field explosions, their damages can affect the safety of the subway after explosion. By using the finite element method, this paper established a coupling “explosive-air-concrete” model and verified the feasibility of the model through experiments. This model can be used in the damage assessment of subway station columns in terms of the bearing capacity, by which the damage of a reinforced concrete column can be divided into different levels. Furthermore, the effect of different parameters on the damage and bearing capacity of the subway station is discussed. The results demonstrate that the stirrup reinforcement ratio of a reinforced concrete is the key factor in determining the column damage under blast loadings. The present study therefore provides a key reference for assessing the damage of subway structures after terrorist attack.

scholarly journals Variable Stiffness Design and Multiobjective Crashworthiness Optimization for Collision Post of Subway Cab Cars

Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 246
Author(s):  
Wei Guo ◽  
Ping Xu ◽  
Zhaofeng Yi ◽  
Jie Xing ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Response Surface ◽  
Energy Absorption ◽  
Pareto Frontier ◽  
Variable Stiffness ◽  
Element Model ◽  
Surface Model ◽  
Front End ◽  
The Finite Element Model

This paper proposes a variable stiffness collision post (VSCP) structure based on a uniform stiffness collision post (USCP) structure and performs stiffness matching optimization for VSCPs. A collision post structure assembled in a subway front-end frame can maintain the living space and absorb a certain amount of the kinetic energy of an impact. The experiment was applied on USCP, and the finite element model was verified experimentally. To investigate the effects of the stiffness parameters of VSCP on the specific energy absorption response (SEA_VSCP) and the area of intrusion response (S_In), response surface models fitted from design of experiment were adopted with the finite element model. In addition, a multiobjective optimization design was realized by using the global response search method and a Pareto frontier sequence was generated, which was based on the developed response surface model. It was found that the optimal value of SEA_VSCP and S_In responses cannot be achieved at the same time. Finally, a grey relational analysis is propounded to attain a desirable balance between SEA_VSCP and S_In from the Pareto frontier sequence under constraints of the peak crash force of VSCP and energy absorption of the front-end of cab car. The optimization result shows that the crashworthiness of VSCP is better than that of USCP.

Simulation of Performance of CFST Elements Containing Differentiated Profile Tubes Filled with Reinforced Concrete

2019 ◽  
Vol 968 ◽  
pp. 281-287 ◽  
Author(s):  
Glib Vatulia ◽  
Alexey Lobiak ◽  
Vitaliy Chernogil ◽  
Mariia Novikova
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Accurate Method ◽  
Iteration Algorithm ◽  
Stress Strain ◽  
Load Bearing Capacity ◽  
Limiting State ◽  
Load Bearing ◽  
The Core

The approach to calculating CFST elements is considered in which physical non-linearity of materials, geometric non-linearity of the tube and the effect of increasing the strength of the core are taken into account. Finite element models are developed and proposed as the basis for more accurate method of calculating concrete-filled steel elements consisting of differentiated profile tubes filled with reinforced concrete. The technique uses a step iteration algorithm involving analytical dependencies and finite element simulation. The criterion for determining the load bearing capacity of CFST elements was the achievement of the stresses in the tube of the characteristic strength. The possibility of estimating the load bearing capacity of elements by limiting stresses in the core concrete is also implemented. The result of the calculations was obtaining the stress-strain and limiting state of the differentiated profile tubes with CFST elements, and graphic analysis of the regularities of stress redistribution at different stages of performance of columns. In general, with the accepted problem statement we could establish the exact stress-strain state, take into account the elastic-plastic deformations of concrete, its cracking and destruction, and geometric nonlinearity of the tube. The effect of performance of the corrugated sheet as a tube was established.

scholarly journals Finite element analysis of reinforced concrete beams with openings in the abdomen and strengthened with steel sleeves based on ANSYS

2020 ◽  
Vol 198 ◽  
pp. 01029
Author(s):  
Yaohui Shen ◽  
Longbin Lin ◽  
Zhengwei Feng
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Circular Hole ◽  
Reinforced Concrete Beam ◽  
Steel Tube ◽  
Reinforced Concrete Beams ◽  
Element Analysis ◽  
Finite Element Software ◽  
Steel Sleeve

The finite element software ANSYS is used to calculate the ultimate bearing capacity of ordinary beam and circular hole beam, and the results are compared with the test values made by predecessors. The value of shear transfer coefficient between cracks of reinforced concrete beam with circular hole in the abdomen in ANSYS finite element simulation is summarized. The coefficient is used to simulate the circular hole beam strengthened by steel sleeve, and it is pointed out that the steel tube is used to reinforce the circular hole beam The effect of tube reinforcement on the bearing capacity of circular hole beam is not obvious.

Bond Strength Models for Adhesively Bonded Flip-Chip Interconnects

2012 ◽  
Author(s):  
K. Sinha ◽  
A. Dasgupta ◽  
J. Caers
Keyword(s):  
Finite Element ◽  
Bond Strength ◽  
Response Surface ◽  
Flip Chip ◽  
Response Surface Model ◽  
Surface Model ◽  
Interfacial Bond Strength ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Bonding Parameters

This paper investigates the role of gold-to-gold interfacial metallurgical bonding on the bond strength of adhesively bonded flip-chip interconnects in microelectronic assemblies. [44] dealt with experimental investigation of the effect of bonding parameters on Au-Au interfacial bond strength. One of the major conclusions in [44] was that interfacial creep deformation closely correlated with the measured evolution of bond strength over time. This study presents a viscoplastic finite element analysis to capture the physical creep mechanisms that drive the development of this strength, so that the effect of the system architecture and bonding parameters can be effectively quantified. Based on the studies in literature [42, 43], the strength is assumed to depend on the area of the contact “a-spots,” which are defined here as the area over which the interfaces come into intimate, atomistically flat contact. The most important inputs to the finite element model consist of (i) interfacial geometry (with special emphasis on the surface roughness topology); (ii) viscoplastic mechanical properties of gold; and (iii) bonding parameters (force, temperature and time). The viscoplastic constitutive properties for gold are obtained partly from experiments conducted in this study and partly from the existing literature. The model inputs are parametrically varied in a systematic way within the design space, to obtain the variability expected in the bond strength. The simulation results are captured in a response surface model that can predict bond strength for a given set of fabrication conditions. The response surface model thus serves as a prediction tool critical for optimizing the interconnect strength and the durability of adhesively bonded flip chip assemblies.

Structural Optimization of a Machining Center Column Based on Response Surface Method

2012 ◽  
Vol 522 ◽  
pp. 663-667
Author(s):  
Ming Nan Sun ◽  
Guo Fu Yin ◽  
Teng Hu
Keyword(s):  
Finite Element ◽  
Structural Optimization ◽  
Response Surface ◽  
Response Surface Method ◽  
Surface Model ◽  
Element Analysis ◽  
Mean Frequency ◽  
Machining Center ◽  
Surface Method ◽  
Design Variables

In order to improve dynamic characteristics of a machining center column, this paper proposes a structural optimization method based on finite element method (FEM) and response surface method (RSM). In order to reduce number of design variables, the finite element analysis samples in design space are selected by using the central composite design (CCD) experiment method. On the basis of FEM results at these experiment samples, quadratic polynomials are employed to establish response surface model, which reflects the relationship between the response (mean frequency of the first four orders) and the design variables (the column structural sizes). The goal of getting maximum mean frequency is reached by using NLPQL algorithm in iSIGHT. Through the optimization, the mean frequency is increased by 8.12%.

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