Computational and Experimental Studies of Cellular Samples Manufactured Using Additive Methods for Use in Advanced Lightweight Designs of Engine Parts

2020 ◽  
Author(s):  
Liubov Magerramova ◽  
Michael Volkov ◽  
Oleg Volgin ◽  
Pavel Kolos
Keyword(s):  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Experimental Studies ◽  
Cellular Structures ◽  
Uniaxial Tensile ◽  
Porous Structures ◽  
Cell Structures ◽  
Engine Part ◽  
Homogeneous Materials ◽  
High Fatigue

Abstract Lattice/cell structures have relatively high characteristics of rigidity and strength, excellent thermal insulation properties, energy absorption characteristics, and high fatigue resistance. The use of this type of structure in engine part construction opens up new opportunities for advanced aviation applications. However, the deformation behavior of porous and metallic structures differs significantly from that of conventional homogeneous materials. Samples with cellular and porous structures are themselves designs. Therefore, procedures for strength testing and interpretation of experimental results for cellular and porous structures differ from those for samples derived from homogeneous materials. The criteria for determining the properties of cellular structures include density, stiffness, ability to accumulate energy, etc. These parameters depend on the configuration of the cells, the size of each cell, and the thickness of the connecting elements. Mechanical properties of cellular structures can be established experimentally and confirmed numerically. Special cellular specimens have been designed for uniaxial tensile, bending, compression, shear, and low-cycle fatigue testing. Several variants of cell structures with relative densities ranging from 13 to 45% were considered. Specifically, the present study examined the stress-strain states of cell structures from brands "CobaltChrome MP1" powder compositions obtained by laser synthesis on an industrial 3D printer Concept Laser M2 Cusing Single Laser 400W. Numerical simulations of the tests were carried out by the finite element method. Then, the most rational cellular structures in terms of mass and strength were established on the basis of both real and numerical experiments.

Computational and Experimental Studies of Cellular Samples Manufactured Using Additive Methods for Use in Advanced Lightweight Designs of Engine Parts

2020 ◽  
Author(s):  
Liubov Magerramova ◽  
Michael Volkov ◽  
Oleg Volgin ◽  
Pavel Kolos
Keyword(s):  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Cell Structure ◽  
Experimental Studies ◽  
Cellular Structures ◽  
Uniaxial Tensile ◽  
Porous Structures ◽  
Lattice Cell ◽  
Cell Structures ◽  
Homogeneous Materials

Abstract The use of cellular structures is one way to reduce the weight of engine parts. Cellular structures are used to provide rigidity and strength for parts subject to compression, bending, and shock loads. Failure of the individual elements of a lattice/cell structure does not result in the destruction of the entire part; this stands in contrast to the structure of a conventional homogeneous metal object, in which cracks will continue to increase with increasing load, causing the destruction of the entire part. Lattice/cell structures have relatively high characteristics of rigidity and strength, excellent thermal insulation properties, energy absorption characteristics, and high fatigue resistance. The use of this type of structure in engine part construction opens up new opportunities for advanced aviation applications. However, the deformation behavior of porous and metallic structures differs significantly from that of conventional homogeneous materials. Samples with cellular and porous structures are themselves designs. Therefore, procedures for strength testing and interpretation of experimental results for cellular and porous structures differ from those for samples derived from homogeneous materials. The criteria for determining the properties of cellular structures include density, stiffness, ability to accumulate energy, etc. These parameters depend on the configuration of the cells, the size of each cell, and the thickness of the connecting elements. Mechanical properties of cellular structures can be established experimentally and confirmed numerically. Special cellular specimens have been designed for uniaxial tensile, bending, compression, shear, and low-cycle fatigue testing. Several variants of cell structures with relative densities ranging from 13 to 45% were considered. Specifically, the present study examined the stress-strain states of cell structures from brands “CobaltChrome MP1” powder compositions obtained by laser synthesis on an industrial 3D printer Concept Laser M2 Cusing Single Laser 400W. Numerical simulations of the tests were carried out by the finite element method. Then, the most rational cellular structures in terms of mass and strength were established on the basis of both real and numerical experiments.

The Effect of Hydrostatic Pressure Environment on the Low Cycle Fatigue Properties of a Maraging Steel

1973 ◽  
Vol 95 (3) ◽  
pp. 157-160 ◽  
Author(s):  
G. Lunsford ◽  
A. W. Pense ◽  
P. S. Venkatesan ◽  
M. J. McIntosh
Keyword(s):  
High Pressure ◽  
Maraging Steel ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Testing Machine ◽  
Fluid Pressure ◽  
Fatigue Properties ◽  
Uniaxial Tensile ◽  
Cycle Fatigue ◽  
Effect Of Hydrostatic Pressure

To investigate the low cycle fatigue properties of an 18 percent nickel maraging steel, a high pressure fatigue testing machine including the high pressure chamber and associated hydraulic controls was designed and developed to apply simultaneously to the specimen (1) constant fluid pressure up to 100,000 psi, (2) mean uniaxial tensile or compressive stress, and (3) alternating push-pull load at a selected rate. Using this machine, notched and unnotched specimens were tested. Results indicated a definite increase in fatigue life of the material in the high pressure environment.

scholarly journals Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4070
Author(s):  
Andrea Karen Persons ◽  
John E. Ball ◽  
Charles Freeman ◽  
David M. Macias ◽  
Chartrisa LaShan Simpson ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Prediction Models ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Wearable Sensors ◽  
Fatigue Tests ◽  
Proof Of Concept ◽  
Cycle Fatigue ◽  
Wearable Sensing ◽  
Failure Data

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from “bench to bedside,” fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

scholarly journals Viscoelastic Properties of Cell Structures Manufactured Using a Photo-Curable Additive Technology—PJM

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1895
Author(s):  
Tomasz Kozior ◽  
Czesław Kundera
Keyword(s):  
Viscoelastic Properties ◽  
Cellular Structure ◽  
Material Selection ◽  
Cellular Structures ◽  
Test Results ◽  
Additive Technology ◽  
Polymer Resin ◽  
Cell Structures ◽  
Relaxation Curves ◽  
The Impact

This research paper reviews the test results involving viscoelastic properties of cellular structure models made with the PolyJet Matrix—PJM additive technology. The designed test specimens were of complex cellular structure and made of three various photo-curable polymer resin types. Materials were selected taking into account the so-called “soft” and “tough” material groups. Compressive stress relaxation tests were conducted in accordance with the recommendations of standard ISO 3384, and the impact of the geometric structure shape and material selection on viscoelastic properties, as well as the most favorable geometric variants of the tested cellular structure models were determined. Mathematica and Origin software was used to conduct a statistical analysis of the test results and determine five-parameter functions approximating relaxation curves. The most favorable rheological was adopted and its mean parameters determined, which enables to match both printed model materials and their geometry in the future, to make a component with a specific rheological response. Furthermore, the test results indicated that there was a possibility of modelling cellular structures within the PJM technology, using support material as well.

Crack mode and life of Ti-6Al-4V under multiaxial low cycle fatigue

2015 ◽  
Author(s):  
Takamoto Itoh ◽  
Masao Sakane ◽  
Takahiro Morishita ◽  
Hiroshi Nakamura ◽  
Masahiro Takanashi
Keyword(s):  
Hollow Cylinder ◽  
Stress Ratio ◽  
Biaxial Loading ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Testing Machine ◽  
Multiaxial Fatigue ◽  
Cycle Fatigue ◽  
Loading Test ◽  
Failure Life

This paper studies multiaxial low cycle fatigue crack mode and failure life of Ti-6Al-4V. Stress controlled fatigue tests were carried out using a hollow cylinder specimen under multiaxial loadings of ?=0, 0.4, 0.5 and 1 of which stress ratio R=0 at room temperature. ? is a principal stress ratio and is defined as ?=sigmaII/sigmaI, where sigmaI and sigmaII are principal stresses of which absolute values take the largest and middle ones, respectively. Here, the test at ?=0 is a uniaxial loading test and that at ?=1 an equi-biaxial loading test. A testing machine employed is a newly developed multiaxial fatigue testing machine which can apply push-pull and reversed torsion loadings with inner pressure onto the hollow cylinder specimen. Based on the obtained results, this study discusses evaluation of the biaxial low cycle fatigue life and crack mode. Failure life is reduced with increasing ? induced by cyclic ratcheting. The crack mode is affected by the surface condition of cut-machining and the failure life depends on the crack mode in the multiaxial loading largely.

scholarly journals Low-cycle fatigue behaviour of laser welded high-strength steel DOMEX 700 MC

2018 ◽  
Vol 157 ◽  
pp. 05013 ◽  
Author(s):  
Peter Kopas ◽  
Milan Sága ◽  
František Nový ◽  
Bohuš Leitner
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
High Strength Steel ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Fatigue Life Analysis

The article presents the results of research on low cycle fatigue strength of laser welded joints vs. non-welded material of high-strength steel DOMEX 700 MC. The tests were performed under load controlled using the total strain amplitude ɛac. The operating principle of the special electro-mechanic fatigue testing equipment with a suitable clamping system was working on 35 Hz frequency. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue parameters. Studies have shown differences in the fatigue life of original specimens and laser welded joints analysed, where laser welded joints showed lower fatigue resistance. In this article a numerical analysis of stresses generated in bending fatigue specimens has been performed employing the commercially available FEM-program ADINA.

The Revised Universal Slope Method to Predict the Low-Cycle Fatigue Lives of Elbow and Tee Pipes

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Hiun Nagamori ◽  
Koji Takahashi
Keyword(s):  
Experimental Data ◽  
Internal Pressure ◽  
Low Cycle Fatigue ◽  
Experimental Studies ◽  
High Accuracy ◽  
Universal Method ◽  
Cycle Fatigue ◽  
Element Analysis ◽  
Slope Method ◽  
Stress States

The stress states of elbow and tee pipes are complex and different from those of straight pipes. The low-cycle fatigue lives of elbows and tees cannot be predicted by Manson's universal slope method; however, a revised universal method proposed by Takahashi et al. was able to predict with high accuracy the low-cycle fatigue lives of elbows under combined cyclic bending and internal pressure. The objective of this study was to confirm the validity of the revised universal slope method for the prediction of low-cycle fatigue behaviors of elbows and tees of various shapes and dimensions under conditions of in-plane bending and internal pressure. Finite element analysis (FEA) was carried out to simulate the low-cycle fatigue behaviors observed in previous experimental studies of elbows and tees. The low-cycle fatigue behaviors, such as the area of crack initiation, the direction of crack growth, and the fatigue lives, obtained by the analysis were compared with previously obtained experimental data. Based on this comparison, the revised universal slope method was found to accurately predict the low-cycle fatigue behaviors of elbows and tees under internal pressure conditions regardless of differences in shape and dimensions.

Superplastic Forming and Pressure Welding of Multilayer Cellular Structures

2012 ◽  
Vol 735 ◽  
pp. 409-414 ◽  
Author(s):  
Rinat V. Safiullin
Keyword(s):  
Titanium Alloy ◽  
Solid State ◽  
Fatigue Testing ◽  
Superplastic Forming ◽  
Cellular Structures ◽  
Pressure Welding ◽  
Joint Formation ◽  
Academy Of Sciences ◽  
Non Destructive

The paper describes the results of long-term investigations on the development of the technology of superplastic forming and pressure welding (SPF/PW) conducted at the Institute for Metals Superplasticity Problems, Russian Academy of Sciences for producing standard articles of aero-space engineering, such as hollow blades, wing and shell panels. The process of solid state joint formation in titanium alloy sheets during SPF was studied. Different investigation techniques were developed. The results of the mechanical and fatigue testing as well as non-destructive inspection of hollow blades are presented. The prospects of the development of the SPF/PW technology are considered and the latest results are discussed.

scholarly journals Estimation of Possibilities of Using Fractal Dimension and Information Entropy of Elastic Waves for Assessment of Damage to Steel 20 at Low Cycle Fatigue

2021 ◽  
Vol 24 (3) ◽  
pp. 17-25
Author(s):  
A.A. Khlybov ◽  
Y.G. Kabaldin ◽  
M.S. Anosov ◽  
D.A. Ryabov ◽  
D.A. Shatagin ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Elastic Wave ◽  
Information Entropy ◽  
Low Cycle Fatigue ◽  
Experimental Studies ◽  
Ultrasonic Signal ◽  
Second Phase ◽  
Cycle Fatigue ◽  
Fatigue Damage Accumulation ◽  
Steel 20

The paper presents the results of experimental studies of specimens made of steel 20 for low-cycle fatigue (cantilever bending). A fatigue curve was obtained for the material under study in the range of stress amplitudes from 210 to 380 MPa. In logarithmic coordinates, this dependence is linear. According to the research results, it has been shown that one of the structure-sensitive characteristics is the shape of an elastic wave pulse transmitted through the medium under study. To analyze the pulse shape of an elastic wave, an algorithm is proposed for assessing the damage of materials, using the values of the fractal dimension of the attractor and the information entropy in the process of fatigue loading. It was found that according to the obtained dependences, the process of fatigue damage accumulation can be conditionally divided into 2 phases. In the first phase, the entropy of the ultrasonic signal practically does not change and remains within the range of 0.05-0.1 nat. The fractal dimension of the attractor of the ultrasonic signal increases from 1.5 to 1.8. During the transition to the second phase, the maximum values of the fractal dimension of the attractor of the ultrasonic signal are observed, the values of which decrease in the second phase to 1.4 before the destruction of the sample. The information entropy values in the second phase increase monotonically up to 0.55 nat. Studies have shown that the obtained dependences practically do not change with a change in the stress amplitude. The results of studies at various stress amplitudes have shown that the characteristics of the fractal dimension of the attractor and the information entropy of elastic wave pulses that have passed through the zones of accumulated damage in the metal expand and supplement the capabilities of acoustic methods in the problems of assessing the performance of materials with low-cycle fatigue and make it possible to identify the stage of destruction of steel 20.

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