Load carrying capacity of functionally graded columns with open cross-sections under static compression

Kędziora²,

Kołakowski

2019

This work deals with the investigation of a steel thin-walled C-column subjected to compression due to temperature increase. These experimental studies of the compressed columns in post-buckling state were conducted to determine their load-carrying capacity. To ensure appropriate supports and keeping of columns, plates with grooves were constructed. The tests of the columns' compression for different preloads were carried out. By comparing the experiment results, numerical calculations based on the finite element method (FEM) and the semi-analytical method (SAM) of solution were performed. The computations were executed with the use of full material characteristics with consideration of large strains and deflections. Furthermore, while observing the deformation of columns, a non-contact Digital Correlation ARAMIS ® system was employed whose calculated results of deformations are very close to the results of the numerical method. The paper revealed that maximum recorded loads under temperature rise are comparable regardless of a value of initial load. A good correlation in results between used methods was achieved. The main goal of the present work was to assess of behavior of thin-walled compressed steel columns in a temperature-controlled environment till their full damage.

Section: Object Of Investigationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Buckling and Post-Buckling of Steel C-Columns in Elevated Temperature

Kędziora²,

Kołakowski

2019

“…or investigations of the frequency of natural vibrations. Such results of buckling and post-buckling of the FGM plate under mechanical loads were included in references [10][11][12][13][14][15][16][17] or were developed for plate structures in reference [18][19][20]. Analyses of natural vibrations of FGM structures were reported in references [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Functionally Step-Variable Graded Plate Under In-Plane Compression

Kołakowski

2019

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.

“…Looking at the most-known compositions as ceramics and metal, ceramics are usually responsible for resistance to high temperatures, but metal can endure most plastic deformations. In regards to the literature, for over thirty years many works were devoted to the theoretical analysis of the behavior of FGM structures under thermal and/or mechanical loads [5][6][7][8][9][10][11][12][13][14][15][16][17]. One of the first works devoted to a study on FGM structures was elaborated by Praveen and Reddy [18], who analyzed the behavior of the plate under static and dynamic loads.…”

Section: Introductionmentioning

confidence: 99%

Study on Strength and Stiffness of WC-Co-NiCr Graded Samples

2019

This work deals with the investigation of the strength and the stiffness of samples built of step-variable functionally graded material (FGM). The considered FGM samples consist of two main components: WC and NiCr with some content of Co as a conjunction of structure. The samples were fabricated on the basis of the detonation gun layer deposition method which is regarded as a novelty in the case of FGM production. The analyzed samples possess a finite number of layers with different varying fractions of each constituent across the wall. The basic tests of bending were conducted to assess the influence of used components in adequate proportions on the stiffness and the total strength in bending. In addition, to validate the numerical approach, simulations of samples under similar loads with truly reflected material distributions were carried out. The material properties of components were determined due to micro-nano-hardness by instrumental indentation techniques. The numerical calculations were performed with the use of the material characteristics for each material and with a consideration of large deflections. Furthermore, by means of an electron microscope, the composition of materials and distribution of chemical elements across the thickness of samples were examined. This paper reveals the experimental results of FGM samples manufactured by detonation gun layer deposition which allows the creation of layer by layer moderately thin-walled structures. It was shown that the indentation method of a determination of Young's modulus gave higher values in comparison to values attained in the bending test. Moreover, it was stated that a modelling of FGM still requires the study of each layer separately to clearly predict the strength of the whole FGM structure.