scholarly journals Mechanical Behavior of the Novel Gradient Concrete Tower of a Cable-Stayed Bridge

2021 ◽  
Vol 8 ◽  
Author(s):  
Zuo-Cai Wang ◽  
Da-You Duan ◽  
Shu-Hang Wang ◽  
Ye Mo ◽  
Yong-Gao Yin

In this paper, the novel gradient concrete is innovatively applied to the bridge towers of Chizhou Yangtze River Bridge to solve the cracking and insufficient durability problems of concrete towers. Fiber-reinforced concrete is used in the outer functional area of the bridge tower, to significantly improve its crack resistance during construction and service. Moreover, the integrated design of anti-cracking and mechanical properties of tower materials is achieved. To study the performance of the novel functional gradient concrete (FGC) tower, the mechanical properties of the FGC tower material are tested, and the overall finite element stress is analyzed. Based on the material properties, the mechanical behavior of the cable-stayed bridge tower is studied. The temperature and stress of the FGC tower during the generation of the hydration heat are compared with that of the ordinary concrete tower. The crack resistance of the FGC tower is analyzed by the finite element method. The results show that the FGC tower has good mechanical properties and durability for the cable-stayed bridge towers.

2021 ◽  
pp. 136943322110015
Author(s):  
Xiao-Li Xie ◽  
Yang Huang ◽  
Xia Qin

In order to overcome the apparent characteristics as a flexible structure of a long-span single-tower cable-stayed bridge and the excessive axial force of the main girder, and to exert the advantages of cable-stayed arch cooperative system bridges, this paper proposes a new type of single-tower cable-stayed arch cooperative system bridge. On the premise of the same amount of steel, the new cooperative system bridge can have a greater stiffness than the existing cable-stayed arch cooperative system bridge with the same span. The new system bridge uses the main girder as the rigid tie bar to balance the arches’ thrusts, which enables the main girder to have a smaller axial force and makes the cable-stayed arch cooperative system bridge a thrustless structure. The proposed bridge is assembled by the following method: (a) constructing a cable-stayed bridge with a steel box girder to bear part of the dead load and to act as a construction platform firstly; (b) then installing arch structures and fixing they with the girder to bear the remaining dead load; and, (c) adding web members between the arch ribs and the girder to form a variable-height truss structure with the arch ribs as the upper chords and the girder as a lower chord to bear most of the live load at last. The underlying mechanical principles were explained, and the mechanical properties of the cooperative system bridges were calculated with the finite element method in this paper. The stiffness and axial forces in the girders are analyzed by the finite element method and compared with those of the conventional bridges. The FEA results show that the new cooperative system bridge has the truss structure’s characteristics, which shows apparent advantages of stiffness and much smaller axial force in the main girder.


2020 ◽  
Vol 20 (06) ◽  
pp. 2050039
Author(s):  
NISANTHKUMAR PANNEERSELVAM ◽  
SREEKUMAR MUTHUSWAMY

Deploying a stent to restore blood flow in the coronary artery is very complicated, as its internal diameter is smaller than 3[Formula: see text]mm. It has already been proven that mechanical stresses induced on stent and artery during deployment make the placement of stent very difficult, besides the development of complications due to artery damage. Various stent designs have already been developed, especially in the metallic category. Still, there are possibilities for developing new stent designs and patterns to overcome the complexities of the existing models. Also, the technology of metallic stents can be carried forward towards the development of bioresorbable polymeric stents. In this work, three new stent cell designs (curvature, diamond, and oval) have been proposed to obtain better performance and life. The finite element method is utilized to explore the mechanical behavior of stent expansion and determine the biomechanical stresses imposed on the stent and artery during the stenting procedure. The results obtained have been compared with the available literature and found that the curvature cell design develops lower stresses and, hence, be suitable for better performance and life.


2018 ◽  
Vol 8 (9) ◽  
pp. 1422 ◽  
Author(s):  
Saman Naghieh ◽  
M. Sarker ◽  
Mohammad Karamooz-Ravari ◽  
Adam McInnes ◽  
Xiongbiao Chen

Three-dimensional (3D) bioplotting has been widely used to print hydrogel scaffolds for tissue engineering applications. One issue involved in 3D bioplotting is to achieve the scaffold structure with the desired mechanical properties. To overcome this issue, various numerical methods have been developed to predict the mechanical properties of scaffolds, but limited by the imperfect representation of one key feature of scaffolds fabricated by 3D bioplotting, i.e., the penetration or fusion of strands in one layer into the previous layer. This paper presents our study on the development of a novel numerical model to predict the elastic modulus (one important index of mechanical properties) of 3D bioplotted scaffolds considering the aforementioned strand penetration. For this, the finite element method was used for the model development, while medium-viscosity alginate was selected for scaffold fabrication by the 3D bioplotting technique. The elastic modulus of the bioplotted scaffolds was characterized using mechanical testing and results were compared with those predicted from the developed model, demonstrating a strong congruity between them. Once validated, the developed model was also used to investigate the effect of other geometrical features on the mechanical behavior of bioplotted scaffolds. Our results show that the penetration, pore size, and number of printed layers have significant effects on the elastic modulus of bioplotted scaffolds; and also suggest that the developed model can be used as a powerful tool to modulate the mechanical behavior of bioplotted scaffolds.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4842
Author(s):  
Huanping Yang ◽  
Wei Zhuang ◽  
Wenbin Yan ◽  
Yaomian Wang

The nanoindentation loading response of elastoplastic materials was simulated by the finite element method (FEM). The influence of the Young’s modulus E, yield stress σy, strain hardening exponent n and Poisson’s ratio ν on the loading response was investigated. Based on an equivalent model, an equation with physical meaning was proposed to quantitatively describe the influence. The calculations agree well with the FEM simulations and experimental results in literature. Comparisons with the predictions using equations in the literature also show the reliability of the proposed equation. The investigations show that the loading curvature C increases with increasing E, σy, n and ν. The increase rates of C with E, σy, n and ν are different for their different influences on the flow stress after yielding. It is also found that the influence of one of the four mechanical parameters on C can be affected by the other mechanical parameters.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4090 ◽  
Author(s):  
Leszek Czechowski ◽  
Zbigniew Kołakowski

A study of the pre- and post-buckling state of square plates built from functionally graded materials (FGMs) and pure ceramics is presented. In contrast to the theoretical approach, the structure under consideration contains a finite number of layers with a step-variable change in mechanical properties across the thickness. An influence of ceramics content on a wall and a number of finite layers of the step-variable FGM on the buckling and post-critical state was scrutinized. The problem was solved using the finite element method and the asymptotic nonlinear Koiter’s theory. The investigations were conducted for several boundary conditions and material distributions to assess the behavior of the plate and to compare critical forces and post-critical equilibrium paths.


Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 525 ◽  
Author(s):  
Nadežda Langová ◽  
Roman Réh ◽  
Rastislav Igaz ◽  
Ľuboš Krišťák ◽  
Miloš Hitka ◽  
...  

The research on population shows that the count of overweight people has been constantly growing. Therefore, designing and modifying utility items, e.g., furniture should be brought into focus. Indeed, furniture function and safety is associated with the weight of a user. Current processes and standards dealing with the design of seating furniture do not meet the requirements of overweight users. The research is aimed at designing flexible chairs consisting of lamellae using the finite element method (FEM). Three types of glued lamellae based on wood with different number of layers and thickness were made and subsequently, their mechanical properties were tested. Values for modulus of elasticity and modulus of rupture were used to determine stress and deformation applying the FEM method for modelling flexible chairs. In this research, the methodology for evaluating the ultimate state of flexible chairs used to analyse deformation and stability was defined. The analysis confirms that several designed constructions meet the requirements of actual standards (valid for the weight of a user up to 110 kg) but fail to meet the requirements for weight gain of a population.


Author(s):  
Belghoul Hakima ◽  
Madani Kouider ◽  
Merdaci Slimane ◽  
Rezgani Laid

This work consists of the study is to analysis by the finite element method the effect of the ageing of the adhesive exposed simultaneously to the temperature and water on the degradation of its mechanical properties and consequently on the transfer of loads from the plate to patch. The stress intensity factor was evaluated according to immersion time and temperature. Several parameters have been taken into consideration, namely the properties of the composite patch, temperature, water absorption, rate and length of crack, the distribution of maximum shear stresses in the adhesive and peel in the patch were also analyzed.


2017 ◽  
Vol 899 ◽  
pp. 272-277
Author(s):  
Hugo Dutra Gomes ◽  
Maria Carolina dos Santos Freitas ◽  
Luciano Pessanha Moreira ◽  
Flavia de Paula Vitoretti ◽  
Jose Adilson de Castro

The present study is primarily engaged in the implementation of the incremental stamping process in a computerized numeric control This paper presents two different approaches to this forming process, an experimental and other numerical. Experimental used by the computer numerical control to perform the printing process and performs numerical simulations of the process using the finite element method. Some parameters are analyzed in both approaches, such as product geometry effects, tool geometry, tool speed, tool path, contact conditions and mechanical properties of the materials.


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