Summary: Three asphalt binders were tested, two paving grade bitumens 35/50 and 50/70 and PMB 25/55-60. Basic characteristics were determined for all binders in three stages: original and after short-term and long-term ageing. The short-term ageing was performed using the RTFOT procedure, and the long-term ageing was performed using the PAV method. The shear stress Superpave fatigue tests, long-time-sweep, and LAS were conducted using a Dynamic Shear Rheometer (DSR) with parallel plates of 8 mm in diameter and a gap of 2 mm in a long-term PAV-aged state. The dataset includes: Basic characteristics of bituminous binder (R&B Temperatur, Penetration, Viscosity), CSV raw data: 01 - R&B and Pen.csv 02 - Dynamic Viscosity.csv FATIGUE parameters: Superpave fatigue factor G*·sin& after PAV: 03 - DSR PAV Superpave fatigue factor.csv Fatigue time-sweep test: 04.1 - 35_50_1 DSR PAV fatigue time-sweep test.csv 04.2 - 35_50_2 DSR PAV fatigue time-sweep test.csv 04.3 - 50_70_1 DSR PAV fatigue time-sweep test.csv 04.4 - 50_70_2 DSR PAV fatigue time-sweep test.csv 04.5 - PMB25_55-60_1 DSR PAV fatigue time-sweep test.csv 04.6 - PMB25_55-60_2 DSR PAV fatigue time-sweep test.csv Linear amplitude sweep (LAS): 05.1 LAS fatigue 35_50.zip 05.2 LAS fatigue 50_70.zip 05.3 LAS fatigue PMB 25_55-60.zip
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The paper presents modeling of bridge elastomeric bearings using large deformation theory and hyperelastic constitutive relations. In this work, the simplest neo-Hookean model was compared with the Yeoh model. The parameters of the models were determined from the elastomer uniaxial tensile test and then verified with the results from experimental bearing compression tests. For verification, bearing compression tests were modeled and executed using the finite element method (FEM) in ABAQUS software. Additionally, the parameters of the constitutive models were determined using the inverse analysis method, for which the simulation results were as close as possible to those recorded during the experimental tests. The overall assessment of the suitability of elastomer bearings modeling with neo-Hookean and Yeoh hyperelasticity models is presented in detail.
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The linear viscoelasticity is still a useful model in the engineering for studying the behavior of materials loaded with different loading rates (frequencies). Certain types of materials reveal also an anisotropic behavior: fiber reinforced composites, asphalt concrete mixtures, or wood, to name a few. In general, researchers try to identify experimentally the dependence of engineering constants like: directional Young’s moduli and Poisson’s ratios on loading velocity by means of creep or harmonic oscillatory tests. This approach is appealing from the experimental point of view. However, from the modeling perspective, this is not the case. The engineering constants emerge in nonlinear manner in the relationship between the strain and stress via fourth order stiffness tensor components. This is especially true in higher order anisotropies, yet even in isotropy Poisson’s ratio appears nonlinearly in the stiffness tensor. Several models for the linear viscoelasticity of anisotropic materials already exist in the literature that try to tackle this issue. In this paper, we propose a linear viscoelasticity model for anisotropic materials based on the spectral decomposition of the stiffness tensor. The proposed model offers several advantages: the natural choice of the stiffness tensor eigenvalues as time-dependent variables, state variables with clear interpretation as creep strains, and reduced burden of storage utilizing the orthogonality of the eigenspaces. We implemented the model in the finite-element method system AceGen/AceFEM, and calibrated parameters of the model with the experimental data available in the literature, thus proving the adequacy of the proposed model to describe anisotropic viscoelastic materials.
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W pracy przedstawiono metody symulacji MES przy szacowaniu nośności stalowych belek dwuteowych poddanych dwukierunkowemu zginaniu ze zwichrzeniem.Analizie nośności granicznej poddano belki z imperfekcjami geometrycznymi
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No abstract is provided for this article.
Przedstawiono metody symulacji statecznościowego zachowania się zginanych elementów konstrukcji stalowych z wykorzystaniem modelowania skończenieelementowego.Rozważania dotyczą belek nieidealnych, wykonanych z walcowanych kształtowników szerokostopowych HEB i wąskostopowych IPE, o wstępnym wygięciu odpowiadającym pierwszej formie zwichrzenia
The main goal of this paper is to propose the performance parameter for binder which is good for quality prediction of asphalt mixture in frame of resistance to permanent deformation (rutting). Additionally, correlation between, proposed by the authors, repeatable shear creep-recovery test carried out on binder and bituminous mixture rutting test is under evaluation. The results are analysed and correlation between the proposed functional parameter and rut depth is shown. Thanks to that it is possible to claim that expensive rutting test procedure can be assisted with simple test carried out in dynamic shear rheometer at the initial mix design procedure.
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Chapter 8 written by Gajewski and Kowalski reviews the most popular methods used in modeling exchange rates, i.e. purchasing power parity and interest rate parity. They attempt to join the two approaches in the empirical part of the study.
Since asphalt mixtures are based on bituminous binders, a complex organic viscoelastic and time-temperature dependent material, they naturally tend to change their performance. Due to increasing traffic and axle loads, fatigue resistance is one of the most important properties of asphalt materials. The standard procedure of asphalt mixture evaluation is determining their fatigue resistance, but it is also possible to determine the fatigue resistance of bitumen on binders level. This article presents the research results of asphalt binders fatigue resistance, two paving grade bitumens and one polymer modified bitumen, in unaged and aged states. Asphalt binders were tested using three methods according to the Superpave criterion, the time-sweep fatigue test and the linear amplitude sweep test (LAS). Analysis and evaluation of the test results were carried out due to fatigue and time consumption of the testing procedure. In terms of determining the fatigue phenomenon, both in bitumen and asphalt mixture levels, the most critical aspect is the time severity of the tests and the necessity to perform such advanced testing on many test specimens. The results show that the G*·sinδ parameter should not be used to validate the fatigue life of bitumen. The result from fatigue time-sweep and LAS tests appear to give similar outcomes and correlate better, especially the LAS in higher strain levels. Furthermore, regarding test time consumption, LAS requires less time to perform and gives a more flexible approach to determining bitumen fatigue life.
Present approach to design of steel I-section beam-columns distinguish two design situations of elements subjected to one directional bending and compression in which they are sensitive either to the flexural failure (second order in-plane bending and compression) or to the flexural-torsional failure (second order spatial bending, warping torsion and compression). This paper refers to the former case of member failure and aims in the development of finite element numerical modelling technique that would be useful for the verification of analytical resistance criteria of perfect beam-column elements subjected to different support and loading conditions. Impact of different boundary conditions and nonuniform bending on the member resistance is assessed and concluding remarks in relation to the proposed analytical formulation are drawn.
