Cast Steel Tests under Thermal Fatigue Conditions

2014 ◽  
Vol 224 ◽  
pp. 105-111
Author(s):  
Adam Lipski ◽  
Stanisław Mroziński

This paper presents results of experimental research and numerical calculations for thermal fatigue of G-X12CrMoVNbN9-1 martensitic cast steel. The tests were performed using hydraulic testing machine equipped with the heating chamber. The experimental research included static tests under mechanical load conditions at four temperature levels (20°C, 400°C, 550°C, 600°C) aimed at determining material characteristics needed for the numerical model. Main cyclic tests were carried out under thermal load conditions. The parameter, which was maintained at unchanged level during tests was the specimen strain ε = const = 0. The specimen temperature was changed. The numerical calculations for the same temperature change program were performed with the use of ABAQUS software. Experimentally and numerically determined stress value versus test time were compared.

2011 ◽  
Vol 82 ◽  
pp. 86-91 ◽  
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni ◽  
Nicoletta Tesio

In this paper the preliminary results of the tensile behavior of reinforced steel in a large range of strain rates are presented. Tensile testing at several strain rates, using different experimental set-ups, was carried out. For the quasi-static tests a universal electromechanical testing machine with the maximum load-bearing capacity of 50 kN was used, while for the intermediate and high-strain rate regimes a hydro-pneumatic apparatus and a JRC-Split Hopkinson Tensile Bar respectively were used. The target strain rates were set at the following five levels: 10-3, 30, 250, 500, and 1000 1/s. The specimens used in this research were round samples having 3mm in diameter and 5mm of gauge length obtained from reinforcing bars. Finally, the material parameters for Cowper-Symonds and Johnson-Cook models were determined.


2009 ◽  
Vol 2 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Hiroyuki Takabayashi ◽  
Shigeki Ueta ◽  
Tetsuya Shimizu ◽  
Toshiharu Noda

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Lei Liu ◽  
Xiang Meng ◽  
Hao Qin ◽  
Zhaozhao Chang

Studying the high-temperature mechanical properties of rocks is of great significance to engineering disasters caused by deep rock mining and underground protection projects. In view of insufficient research on the high-temperature mechanical properties of deep rocks in southwestern China, we used high-temperature heating devices and statics equipment to conduct static tests on Skarn. XW7L-12 box-type resistance furnace was adopted to heat Skarn (25°C, 200°C, 400°C, 600°C, and 800°C), and the temperature effect of its basic physical parameters (density and wave velocity) was measured and analyzed. Uniaxial compression experiments were performed on two cooling methods of Skarn (natural cooling and water cooling) by a constant stress pressure testing machine to obtain a stress-strain curve and analyze its statics index (peak strength, tensile strength, elastic modulus, and peak strain) and the change rule of failure mode with temperature rise and different cooling methods. With the temperature increasing, various static mechanical indexes of Skarn will be greatly affected. Meanwhile, the different cooling methods are not related to the change trend of the mechanical properties of Skarn under high temperature.


2013 ◽  
Vol 690-693 ◽  
pp. 211-217
Author(s):  
Jin Gui Qin ◽  
Fang Yun Lu ◽  
Yu Liang Lin ◽  
Xue Jun Wen

Results of uni-axial tensile loading of three automotive steels at different strain rates (0.0011–3200s-1) are reported here. Quasi-static tensile tests were performed under the strain rate of 1.1×10-3 s-1 using an electromechanical universal testing machine, whereas dynamic tests were carried out under the strain rate in the range of 1100 to 3200 s-1 using a Split Hopkinson Tensile Bar apparatus. Based on the experimental results, the material parameters of widely used Johnson–Cook model which described the strain rate and temperature-dependent of mechanical behaviour were determined. The experiments show that strain-rate hardening is superior to thermal softening: yield stresses, tensile strength, deformation, and energy dissipation increase with the strain rate from quasi-static tests to dynamic tests. The Johnson–Cook model can describe the behaviour of these steels and provides the opportunity to study the material and structural response.


Author(s):  
Roland Mu¨cke ◽  
Klaus Rau

Modern heavy-duty gas turbines operate under hot gas temperatures that are much higher than the temperature capability of nickel superalloys. For that reason, advanced cooling technology is applied for reducing the metal temperature to an acceptable level. Highly cooled components, however, are characterised by large thermal gradients resulting in inhomogeneous temperature fields and complex thermo-mechanical load conditions. In particular, the different rates of stress relaxation due to the different metal temperatures on hot gas and cooling air exposed surfaces lead to load redistributions in cooled structures, which have to be considered in the lifetime prediction methodology. In this context, the paper describes Coupled Thermo-Mechanical Fatigue (CTMF) tests for simultaneously simulating load conditions on hot and cold surfaces of cooled turbine parts, Refs [1, 2]. In contrary to standard Thermo-Mechanical Fatigue (TMF) testing methods, CTMF tests involve the interaction between hot and cold regions of the parts and thus more closely simulates the material behaviour in cooled gas turbine structures. The paper describes the methodology of CTMF tests and their application to typical load conditions in cooled gas turbine parts. Experimental results are compared with numerical predictions showing the advantages of the proposed testing method.


Author(s):  
A. A. N. Aljawi ◽  
A. A. A. Alghamdi ◽  
T. M. N. Abu-Mansour

In this paper, an innovative mode of deformation of the frusta is presented and discussed in details. A full experimental investigation for the quasi-static axial inversion of right circular frusta is given. The experimental work includes studying the effect of frusta wall thickness, angle of frusta and material type on the inversion of the frusta. The quasi-static tests were conducted on an Instron Universal testing machine and qualitative dynamic test were carried using Drop Hammer Facility. Finite element (FE) modeling of the inversion mode is carried out by using ABAQUS FE package. Analysis of the deformation modes is examined using a non-linear model of the finite element package. The FE findings are reported and modes of deformation during the inversion of aluminum frusta are described under quasi-static and dynamic cases. Furthermore, a good agreement is reported between the finite element force histories and the experimental results.


2020 ◽  
Vol 310 ◽  
pp. 00054
Author(s):  
Miroslaw Wieczorek

The paper presents the numerical analysis of the impact of removing a corner column on the behavior of a continuous slab-column structure. The model uses the minimal reinforcement amount compliant with Eurocodes. The basis for numerical modelling was the experimental research of a piece of a slab-column structure with the dimensions of 3.0×3.0 m in column axes. The article includes a detailed description of the assumed conditions of the model support, the method of loading and reading of the results. The paper also compares the obtained results of numerical calculations with experimental results.


2014 ◽  
Vol 926-930 ◽  
pp. 4101-4104
Author(s):  
Bo Wang

In order to understand bursting liability and related mechanical properties of roof mudstone in east mine of Kouzi, SANS material mechanics testing machine is utilized as power equipment, bursting liability and related mechanical properties of roof mudstone has been tested, and MATLAB is exploited to analyze mathematical analysis for results. Experimental results showed that roof rock with strong bursting liability in east mine of Kouzi, its relevant safety should be improved; we can adopt the way of water injection into roof strata to change its mechanical properties, the purpose of safe mining is achieved. Research conclusion provides theoretical basis for safety mining in deep Yongchuan mine in east of Kouzi.


2016 ◽  
Vol 710 ◽  
pp. 295-300
Author(s):  
Dianne van Hove ◽  
Frans Soetens

Welded joints in a 30 meter span aluminium truss girder were investigated numerically and experimentally. Since aluminium design rules for welded K-and N-joints in CHS truss girders were lacking the joints were checked using steel design rules. Calculations showed that the N-joints were governing for chord and brace sizes. Further numerical analysis on the N-joints using ANSYS 11.0 was carried out. Full scale experimental research was successfully carried out for validation of the numerical calculations. It is concluded that steel design rules predict the failure behavior and failure mode of the considered aluminium N-joints well. However, steel design rules overestimate the failure load by 8% for the truss configurations investigated.


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