|ชื่อเรื่อง||:||Computational mesoscale modelling of concrete material under high strain rate loading|
|คำค้น||:||mesoscale , strain rate , dynamic increase factor , DIF|
|หน่วยงาน||:||Edinburgh Research Archive, United Kingdom|
|ผู้ร่วมงาน||:||Lu, Yong , Rotter, Michael|
|ความสัมพันธ์||:||Song, Z.H. and Lu, Y. (2011). Mesoscopic analysis of concrete under excessive high strain-rate compression and implications on interpretation of test data. Journal of Impact Engineering, 46. , Song, Z.H. and Lu, Y. (2011). Numerical simulation of concrete confined by transverse reinforcement. Computers and Concrete, 8(1). , Song, Z.H. and Lu, Y. (2011). An algorithm for generation of 3D meso-structure of concrete for finite element analysis. 19th Association of Computational Mechanics for Engineering Conference. Edinburgh, UK. , Song, Z.H. and Lu, Y. (2010). Concrete response to higher strain rate compression using mesoscopic analysis. The First International Conference of Protective Structures. Manchester, UK. , Lu, Y. and Song, Z.H. (2011). A mesoscopic modelling perspective of response of concrete to high strain-rate loading. Eighth International Conference on Structural Dynamics. Leuven, Belgium. , Lu, Y., Song, Z.H. and Tu, Z.G. (2010). Analysis of dynamic response of concrete using a mesoscale model incorporating 3D Effects. International Journal of Protective Structures, 1(2). , Lu, Y., Song, Z.H. and Tu, Z.G. (2009). Numerical simulation study of the strain rate effect on concrete in compression considering material heterogeneity. 9th Int. Conf. on the Mechanical and Physical Behaviour of Materials under Dynamic Loading. Brussels, Belgium. , Lu, Y., Song, Z.H. and Tu, Z.G. (2009). Mesoscale analysis of concrete material under dynamic loading, International Workshop on Structures Response to Impact and Blast. Haifa, Israel.|
Cement-based composite materials are widely used in engineering applications. The strength and damage patterns of such materials depend upon the properties of the constituent components as well as the microstructure. Three scale levels are generally recognized in the analysis of the mechanical behaviour of composites, namely, macro-scale, meso-scale, and nano- or atomistic scale. Modelling of the mechanical properties at the meso-level provides a powerful means for the understanding of the physical processes underlying the macroscopic strength and failure behaviour of the composite materials under various loading conditions. This thesis endeavours to develop effective and efficient mesoscale models for cement-based composites, especially concrete, with a focus on dynamic analysis applications and in a three-dimensional stress-strain environment. These models are subsequently applied to investigate the intrinsic microscopic mechanisms governing the behaviour of such material under complex and high rate loadings, such as those due to shock, impact and blast. To cater to the needs of dynamic analysis under complex stress conditions, a general 2-dimensinal (2D) mesoscale modelling framework is further developed with the incorporation of the 3-D effect. This framework integrates the capabilities of MATLAB programming for the generation of the mesoscale geometric structure, ANSYS-CAE for finite element mesh generation, and the hydrocode LS-DYNA for solving the dynamic response of the model. The 3D effect is incorporated via a novel pseudo-3D modelling scheme such that the crucial lateral confinement effect during the transient dynamic response can be realistically represented. With the above mesoscale model a comprehensive investigation is conducted on the dynamic increase factor (DIF) in the concrete strength under compression, with particular focus on the variation trend at different strain rate regimes, and the key influencing factors. The wave propagation effect under high strain rate is scrutinised from a strip-by-strip perspective, and the correlation between the externally measured stress-strain quantities and the actual processes within the specimen is examined. The contribution of the material heterogeneity, as well as the structural effect (inertia), in the dynamic strength enhancement is evaluated. The classical Brazilian (splitting) test for the dynamic tensile behaviour of concrete is also investigated with the aid of the mesoscale model. Of particular interest here is the validity of such an indirect setup in reproducing the tensile behaviour of the specimen under high strain rates, as well as the effect of the heterogeneity in the dynamic tensile strength. Complications are found to arise as the loading rate increases. The change of the damage patterns with increase of the loading rate and the implications on the interpretation of the results are discussed. As an ideal solution to modelling of the 3-D effects, a methodology for the creation of a complex real 3-dimensional mesoscale model is put forward in the last part of the thesis. A geometric concept, called convex hull, is adopted for the representation of aggregates, and this makes it possible to utilize the relevant algorithms in computational geometry for the present purpose of generation of random 3-D aggregates. A take-and-place procedure is employed to facilitate the generation of the complete 3-D meso-structure. Associated techniques are developed for fast detection of particle inclusion-intersection. An example 3D mesoscale model is presented and representative numerical simulations are carried out to demonstrate the performance of the 3-D mesoscale modelling scheme.
Song, Zhenhuan . (2556). Computational mesoscale modelling of concrete material under high strain rate loading.
กรุงเทพมหานคร : Edinburgh Research Archive, United Kingdom .
Song, Zhenhuan . 2556. "Computational mesoscale modelling of concrete material under high strain rate loading".
กรุงเทพมหานคร : Edinburgh Research Archive, United Kingdom .
Song, Zhenhuan . "Computational mesoscale modelling of concrete material under high strain rate loading."
กรุงเทพมหานคร : Edinburgh Research Archive, United Kingdom , 2556. Print.
Song, Zhenhuan . Computational mesoscale modelling of concrete material under high strain rate loading. กรุงเทพมหานคร : Edinburgh Research Archive, United Kingdom ; 2556.