Analysis of Deformation for PC Thin-Wall Box Girders Exposed to Fire

2011 ◽  
Vol 368-373 ◽  
pp. 930-933
Author(s):  
Wei Hou ◽  
Shuan Hai He ◽  
Cui Juan Wang ◽  
Gang Zhang

Being aimed to deformation problem of pre-stressed concrete thin-walled multi-room box girders exposed to co-action of fire and load, on the basis of enthalpy conduction model and thermo-mechanics parameters, the finite element procedure was applied to analyze the deformation of three spans pre-stressed concrete thin-walled multi-room box girders exposed to co-action of fire and load. In conclusion, the deflection is obvious under action of the variation width and fire load model.

2021 ◽  
Vol 233 ◽  
pp. 111867
Author(s):  
Xiayuan Li ◽  
Shui Wan ◽  
Yuanhai Zhang ◽  
Maoding Zhou ◽  
Yilung Mo

1983 ◽  
Vol 27 (04) ◽  
pp. 281-285
Author(s):  
K. Rajagopalan ◽  
C. Ganapathy Chettiar

A finite-element procedure for the determination of buckling pressure of thin-walled cylindrical shells used in ocean structures is presented. The derivation of the elastic and geometric stiffness matrices is discussed in detail followed by a succinct description of the computer program developed by the authors during the course of this study for the determination of the buckling pressure. Particular attention is paid to the boundary conditions which strongly influence the buckling pressure. Applications involving the interstiffener buckling in submersible hulls and cylindrical shells with stepwise variation in wall thickness are considered and the results compared with the solutions and procedures available in the literature.


Author(s):  
V. Verma ◽  
K. Nallasivam

Purpose: The primary objective of the current study is to numerically model the steel thin-walled curved box-girder bridge and to examine its various response parameters subjected to Indian Railway loading. Design/methodology/approach: The analysis is conducted by adopting a one dimensional curved thin-walled box-beam finite beam element based on finite element methodology. The scope of the work includes a computationally efficient, three-noded, one-dimensional representation of a thin-walled box-girder bridge, which is especially desirable for its preliminary analysis and design phase, as well as a study of the static characteristics of a steel curved bridge, which is critical for interpreting its dynamic response. Findings: The analytical results computed using finite element based MATLAB coding are presented in the form of various stress resultants under the effect of various combinations of Indian Railway loads. Additionally, the variation in different response parameters due to changes in radius and span length has also been investigated. Research limitations/implications: The research is restricted to the initial design and analysis phase of box-girder bridge, where the wall thickness is small as compared to the cross-section dimensions. The current approach can be extended to future research using a different method, such as Extended finite element technique on curved bridges by varying boundary conditions and number of elements. Originality/value: The validation of the adopted finite element approach is done by solving a numerical problem, which is in excellent agreement with the previous research findings. Also, previous studies had aimed at thin-walled box girders that had been exposed to point loading, uniformly distributed loading, or highway truck loading, but no research had been done on railway loading. Moreover, no previous research had performed the static analysis on thin-walled box-girders with six different response parameters, as the current study has. Engineers will benefit greatly from the research as it will help them predict the static behaviour of the curved thin-walled girder bridge, as well as assess their free vibration and dynamic response analysis.


2012 ◽  
Vol 204-208 ◽  
pp. 2188-2191 ◽  
Author(s):  
Gang Zhang ◽  
Shuan Hai He ◽  
Hong Jun Guo ◽  
Wei Hou

The deflection for pre-stressing concrete thin-wall box girders bridges under action of multi-span loads exposed to fire was presented in this paper. Based on thermal and mechanics parameters, the fire and load model was designed, the space analysis procedure was performed to analyze the maximum deflection of each span during prophase and anaphase of extending-fire time, altogether 4 kind of load case. The studied results indicate: under condition of the whole span fire and load model of multi span, the mid-span deflection of the second span is down-warping during the fire prophase which its time is about 20 minutes, and up-warding or horizontal during the fire anaphase which its time is about 50 minutes; the deflection of the first and third span is down-warping with extending time during the whole fire time.


2006 ◽  
Vol 326-328 ◽  
pp. 1599-1602
Author(s):  
Bo Sung Shin

High-speed machining (HSM) is very useful method as one of the most effective manufacturing processes because it has excellent quality and dimensional accuracy for precision machining. Recently micromachining technologies of various functional materials with very thin walls are needed in the field of electronics, mobile telecommunication and semiconductors. However, HSM is not suitable for microscale thin-walled structures because of the lack of their structure stiffness to resist high-speed cutting force. A microscale thin wall machined by HSM shows the characteristics of the impact behavior because the high-speed cutting force works very shortly on the machined surface. We propose impact analysis model in order to predict the limit thickness of a very thin-wall and investigate its limit thickness of thin-wall manufactured by HSM using finite element method. Also, in order to verify the usefulness of this method, we will compare finite element analyses with experimental results and demonstrate some applications.


Machines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 68
Author(s):  
Lisa Croppi ◽  
Niccolò Grossi ◽  
Antonio Scippa ◽  
Gianni Campatelli

The turning of thin-walled components is a challenging process due to the flexibility of the parts. On one hand, static deflection due to the cutting forces causes geometrical and dimensional errors, while unstable vibration (i.e., chatter) could compromise surface quality. In this work, a method for fixturing optimization for thin-walled components in turning is proposed. Starting from workpiece geometry and toolpath, workpiece deflections and system dynamics are predicted by means of an efficient finite element modeling approach. By analyzing the different clamping configurations, a method to find the most effective solution to guarantee the required tolerances and stable cutting conditions is developed. The proposed method was tested as a case study, showing its application and achievable results.


2013 ◽  
Vol 690-693 ◽  
pp. 914-918
Author(s):  
Yue Hong Li ◽  
Bai Shou Li

In order to study ribbed thin-walled square steel tube recycled concrete eccentric compression column, used the mechanical properties of ANSYS software, conduct the nonlinear numerical simulation. The analysis of the ribbed and ribbed, recycled coarse aggregate replacement ratio and eccentricity, three factors on the eccentric compression column mechanical performance, proved the thin-walled square steel tube that recycled concrete composite column the effectiveness of three-dimensional finite element simulation. The result shows that: when aggregate replace rate was 0%, ribbed specimen than not ribbed specimen axial displacement and displacement to the reduced to 5.77% and 2.33% respectively. When the aggregate replace rate was 50%, ribbed specimen than not ribbed specimen shaft voltage and bias displacement has been reduced by 6.53% and 4.22%; When the aggregate replace rate was 0%, ribbed specimen than not ribbed specimen axis pressure bearing capacity and bias the bearing capacity increased by 1.21% and 2.74%. When the aggregate replace rate was 50%, ribbed specimen than not ribbed specimen axis pressure bearing capacity and bias the ultimate bearing capacity increased by 1.04% and 2.82%.


Author(s):  
Xiaodong Tang ◽  
James C. Cheng

Abstract Using beam element in finite element analysis of automotive structures in the event of crash may significantly reduces the number of elements required to model the structures. It may significantly reduces the computing time for nonlinear integration. More significantly, it takes less time to establish, post-process and modify the models and is therefore, suitable for upfront engineering and concept analysis at early design stages. Considerable studies on beam elements (1–4) have been conducted and many commercial and academic finite element codes (5–7) incorporated it in their libraries. These beam elements are mostly based on the traditional theory that considers the deformation due to yielding and large displacement. However, the buckling phenomenon in the thin-walled components is not reflected in the formulation and therefore, the element are not suitable for thin-walled beams which are quite common in vehicle structures. In this study, a thin-walled beam element is developed to incorporate both the deformation due to material yielding and the deformation due to the buckling of the thin wall plates. The buckling characteristics of the plates is approximately and equivalently converted into the behavior of crush hinge. Like the conventional plastic hinges, the crush hinges are formulated into the finite beam element. The element buckling effect is reflected into the structural response. The beam element is coded into a computer program. The major formulations of beam element, numerical integration schemes of dynamic analysis and contact loading are illustrated in the follow sections. The computer program is used to analyze vehicle structures and the examples are shown in this paper. It should be pointed out that due to the limitations of beam element it is not possible to consider local design features such as small holes and notches. In those cases approximation must be adopted in finite element modeling.


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