Composite element algorithm for the thermal analysis of mass concrete

Abstract

Purpose -Pipe cooling is an important measure for controlling the temperature in mass concrete. Since the temperature field in mass concrete containing cooling pipes is unsteady and three-dimensional, and there are huge quantities of the cooling pipes in the concrete, the study of efficient and reliable algorithm is crucial. The purpose of this paper is to develop the composite element method (CEM) for the temperature field in mass concrete containing cooling pipes. Design/methodology/approach -Each cooling pipe segment is looked at as a special sub-element having definite thermal characteristics, which is located explicitly within the composite element. By the variational principle, the governing equation for the composite element containing cooling pipes is established. Findings -One of the remarkable advantages of the method proposed is that each cooling pipe can be simulated explicitly while the difficulty of mesh generation around cooling pipes can be avoided. Originality/value -The paper demonstrates how composite elements containing cooling pipes are degenerated to the conventional finite elements automatically when the first stage artificial cooling finished, and conversely, the conventional finite elements can also be transformed to the composite elements automatically when the second stage artificial cooling started. The comparison of the numerical example using FEM and CEM shows the rationality of the proposed method.

Effect of pipe-cooling system on thermal-mechanical behaviour of PC box bridge girders at hydration age

“…At present, some scholars have proposed a three-stage pipe-cooling method for mass concrete (Chen et al 2011;Cheng et al 2016). The purpose of the first stage is to reduce the peak temperature of concrete, the second stage aims to disperse temperature difference and reduce the consequent stress, and the last stage is to stabilize the temperature of concrete.…”

“…Nowadays, many technologies have been proposed to prevent thermal cracking caused by cement hydration heat, such as pre-cooling, pipecooling, surface thermal blankets and low heat cement (Kim et al 2015;Kodur et al 2016;Schackow et al 2016). Cooling by flow water through an embedded pipe is a common artificial temperature control measure on concrete dams, foundations and other mass concrete structures (Chen et al 2011;Liu et al 2015;Zuo et al 2014).…”

“…However, little research on PC box girders is reported due to structural complexity of PC box bridge girders on the pier top, and large number of prestressing strands within body of girders (Zhang et al 2017). Many methods have been proposed, such as pseudo three-dimensional finite element methods (Myers et al 2009), thermal-fluid coupling method (Liu et al 2013), p-version finite element method (Zuo et al 2015) and composite-element method (Chen et al 2011) to obtain more accurate calculation method for pipe-cooling system. In the thermal-fluid coupling method, the position and size of pipe are accurately modelled according to the design, which can accurately simulate the convection heat transfer between cooling water and concrete, and temperature rise of cooling water along pipe due to heat generated by cement hydration (Cheng et al 2016;Liu et al 2013;Liu et al 2015).…”

Thermal Cracking Analysis during Pipe Cooling of Mass Concrete Using Particle Flow Code

“…In order to strengthen the control on the system, a series of numerical simulations has been performed [2][3][4]. Most current simulations on thermal fields of mass concrete are based on the finite element method [5,6] and composite element method [7]. In recent few years, the heat-fluid pipe element method has been created as a better simulation method [8].…”

Finite element analysis on hot deformation behavior of TiC-particle-reinforced titanium matrix composite

“…The cost of experiment is large and the results are relatively discrete because of the changes of experimental and environmental conditions, which make the limit experimental results unable to reflect the true mechanical properties. With fast development of computers, numerical simulations have been gradually accepted by scientists worldwide (Chen et al, 2011;Momin et al, 2012). Tirosh et al (1995) reported the distribution of the stress field of particle-reinforced composites by using FEA, and they also quantitatively investigated the fracture criteria for the interfacial debonding.…”