Research on Creep Behavior of Three-Point Bending Specimen with Fixed Constraints at the Large Deformation Stage

2021 ◽  
Author(s):  
Xiao Han ◽  
Haiyang Yu ◽  
Guo-Yan Zhou ◽  
Fakun Zhuang ◽  
Shan-Tung Tu
Keyword(s):  
Aluminum Alloy ◽  
Large Deformation ◽  
Creep Deformation ◽  
Deformation Theory ◽  
Equivalent Stress ◽  
Small Deformation ◽  
Test Technique ◽  
Three Point Bending ◽  
Deformation Stage ◽  
General Deformation

Abstract Three-point bending specimen with fixed constraints (TPBSF) is a novel small specimen test technique, which can simultaneously obtain creep deformation and creep fracture data. However, the current researches are only focused on the small deformation theoretical analysis, which is contrary to the actual experiment results. In this study, the general deformation theory was introduced to analyze creep deformation behavior of TPBSF at the large deformation stage. Based on this theory, the equivalent stress and strain were analyzed. Then the feasibility and accuracy were verified by comparing with the experimental data of A7N01 aluminum alloy at 380 ?. The results show that the regressed creep parameters agree well with those from the uniaxial ones. It can be found that the equivalent stress obtained by the general deformation theory can be well used to life prediction analysis of A7N01 aluminum alloy.

scholarly journals A new approach for the fracture grouting pressure in soil mass

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878643
Author(s):  
Zhi-bin Wang ◽  
Jin-feng Zou ◽  
Hai Yang
Keyword(s):  
Large Deformation ◽  
Failure Criterion ◽  
Deformation Theory ◽  
Small Deformation ◽  
Soil Mass ◽  
Parameter Analysis ◽  
Strength Failure ◽  
Grouting Pressure ◽  
Fracture Grouting ◽  
Coulomb Failure Criterion

This study focuses on analytical solutions of the fracture grouting pressure. Based on the cavity expansion and fracture grouting mechanism, the small deformation in the elastic zone, large deformation in the plastic zone, and non-associated flow rules are assumed. The solutions of the fracture grouting pressure based on the Unified Strength failure criterion, spatial mobilized plane criterion, Mohr–Coulomb failure criterion, and modified Cambridge model (MMC) are proposed for the large-deformation and small-deformation assumptions, respectively. A parameter analysis was conducted to analyze the differences between large-deformation and small-deformation theories. A comparison of the local test data with theoretical results reveals that the Cambridge model is more suitable for weakly consolidated soil and that the Mohr–Coulomb theory is suitable for over-consolidated soil. For all yield criteria in the study, the analysis indicates that the large-deformation theory has more reliable results than the small-deformation theory. The results in this study can direct the design and operation of fracture grouting.

Research on the Conversion Relationship for Three-Point Bending Specimen With Fixed Constraints in the Large Deformation Stage

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Hai-Yang Yu ◽  
Guo-Yan Zhou ◽  
Fa-Kun Zhuang
Keyword(s):  
Large Deformation ◽  
Creep Test ◽  
Geometric Parameters ◽  
Test Method ◽  
Three Point Bending ◽  
Deformation Stage ◽  
Creep Stress ◽  
Uniaxial Creep ◽  
Conversion Coefficients ◽  
Beam Bending

Abstract In this study, based on the rod tensile model, a conversion relationship between three-point bending specimen with fixed constraints (TPBSF) and uniaxial creep data in the large deformation stage is defined by the reference stress method. Using finite element method, conversion coefficients are determined. Then it is verified by the creep test data of A7N01 at 350 °C (Zhuang, F. K., 2014, “Research on Creep Test Method of Small Specimen Based on Beam Bending Theory,” Ph.D. thesis, East China University of Science and Technology, Shanghai, China). The results show that creep stress exponent n is the same, but creep constant B obtained by rod tensile model is much closer to uniaxial creep than beam bending model. Finally, effects of geometric parameters and friction on conversion coefficients are investigated. On this basis, the specimen cross section aspect ratio greater than 1 and the indenter radius larger than 1 mm are recommended to minimize the influence of TPBSF geometric parameters on conversion coefficients. The influence of friction on conversion coefficients can be negligible.

scholarly journals Relationship between advancing abutment pressure and deformation of surrounding rock in a roadway: A case study in Helin coal mine in China

2021 ◽  
Author(s):  
Hongyan Qin ◽  
Zhiheng Cheng ◽  
Zhenhua Ouyang ◽  
Xidong Zhao ◽  
Jicheng Feng
Keyword(s):  
Large Deformation ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Small Deformation ◽  
Surrounding Rock ◽  
Rock Stress ◽  
Deformation Stage ◽  
Original Rock ◽  
Rapid Deformation ◽  
Peak Value

Abstract The deformation stages of the working face of a mine in front of the roadway were defined based on the location of the roadway and the coal wall in different deformation zones. Observational data of the advancing abutment pressure and the surrounding rock deformation of the roadway from Helin coal mine were analyzed using least squares fitting. The results show that the distance between the boundary of the rapid deformation stage and the deceleration deformation stage and the position where the advancing abutment pressure is equal to the original rock stress is 0.8 m. The distance between the boundary of the large deformation stage and the stable small deformation stage and the peak value of the advancing abutment pressure is 0.3 m. A theoretical analysis indicated that the boundary between the rapid deformation stage and the deceleration deformation stage is located at the intersection of the advancing abutment pressure curve and the original rock stress curve. The boundary between the large deformation stage and the stable small deformation stage is located at the peak value of the advancing abutment pressure.

A Study of the Effect of Pre-Straining on Angular Distortion in One-Pass Fillet Welding Incorporating Large Deformation Theory

1995 ◽  
Vol 209 (5) ◽  
pp. 401-409 ◽  
Author(s):  
K-Y Bae ◽  
S-J Na
Keyword(s):  
Large Deformation ◽  
Initial Stress ◽  
Deformation Theory ◽  
Small Deformation ◽  
Angular Distortion ◽  
Stress Effect ◽  
The Finite Element Method ◽  
Concentrated Load ◽  
Fillet Welding ◽  
Updated Lagrangian

By using the finite element method based on the large deformation theory, the effect of pre-straining on angular distortion of one-pass fillet weldments was analysed for the free-end and constrained-end condition. Pre-straining by an additional concentrated load caused a large thermal deformation during heating, and reduced the reverse distortion during cooling and consequently the residual distortion. Geometric change of the fillet weldment caused by pre-straining during welding induced an initial stress effect on the stiffness to the further deformation, which is due to a developed in-plane stress. This initial stress effect could be considered in the large deformation theory to be based on the updated Lagrangian method, while it could not in the small deformation theory. As the pre-straining load increased in the free-end condition, the initial stress effect also increased. In the constrained-end condition, the initial stress effect played an important role in the deformation of the fillet weldment, even without pre-straining. By comparing the results predicted by the large deformation theory with those by the small deformation theory and experiments, it can be shown that the large deformation theory is able to describe the distortion phenomenon in fillet welding reasonably well.

Analysis of Large Deformation Wound Roll Models

2013 ◽  
Vol 80 (4) ◽  
Author(s):  
C. Mollamahmutoglu ◽  
J. K. Good
Keyword(s):  
Large Deformation ◽  
Deformation Theory ◽  
Computation Time ◽  
Small Deformation ◽  
Linear Analysis ◽  
Strain Theory ◽  
Metal Foil ◽  
Linear Strain ◽  
Almost All ◽  
Deformation Models

Almost all winding models incorporate the assumption of small linear deformations and strain in their development. These models treat the addition of a layer of web to a winding roll with linear analysis using linear strain theory. Very few winding models have been developed that incorporate large deformation theory although many models treat material nonlinearity. Tissue and nonwoven webs are highly extensible in-plane and highly compressible in the thickness dimension when compared to paper, plastic film, and metal foil webs. Winding models that embody large deformation theory should apply to all web materials. Such models may be wasteful in computation time for web materials such as paper, film, and foils where models that employ small deformation theory may provide sufficient accuracy. This would appear deterministic based upon the extensibility and compressibility of a web material, but the issue becomes more complex due to limitations in tension that can be exerted on the webs. Herein, a large deformation winding model will be developed. Results from this model will be used to benchmark results from other small and large deformation models, and with laboratory test data, a review of all results will be used to determine when or if large deformation winding models are required.

scholarly journals Mechanics of moving defects in growing sheets: 3-d, small deformation theory

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Amit Acharya ◽  
Shankar C. Venkataramani
Keyword(s):  
Deformation Theory ◽  
Small Deformation

Mechanical properties of the tadpole tail fin

1998 ◽  
Vol 201 (19) ◽  
pp. 2691-2699 ◽  
Author(s):  
PA Doherty ◽  
RJ Wassersug ◽  
JM Lee
Keyword(s):  
Stress Relaxation ◽  
Large Deformation ◽  
Forced Vibration ◽  
Viscoelastic Properties ◽  
Developmental Plasticity ◽  
Rana Catesbeiana ◽  
Small Deformation ◽  
Collagen Fibres ◽  
Tadpole Tail ◽  
Undulatory Swimming

The tadpole tail fin is a simple double layer of skin overlying loose connective tissue. Collagen fibres in the fin are oriented at approximately +/-45 degrees from the long axis of the tail. Three tests were conducted on samples of the dorsal tail fin from 6-10 Rana catesbeiana tadpoles to establish the fin's viscoelastic properties under (1) large-deformation cyclic loading at 1 and 3 Hz, (2) small-deformation forced vibration at 1 and 3 Hz, and (3) stress relaxation under a 0.1 s loading time. The fin was very fragile, failing easily under tensile loads less than 7 g. It was also strikingly viscoelastic, as demonstrated by 72+/-1 % hysteresis loss (at 3 Hz), 16+/-3 % stress remaining after 100 s of stress relaxation and a phase angle of 18+/-1 degrees in forced vibration. As a consequence of its viscoelastic properties, the fin was three times stiffer in small than in large deformation. This may account for the ability of the fin to stay upright during normal undulatory swimming, despite the absence of any skeletal support. Tadpoles in nature are often found with damaged tails. We suggest that the unusually viscoelastic and fragile nature of the fin helps tadpoles escape the grasp of predators. Because the fin deforms viscoelastically and tears easily, tadpoles can escape predators and survive otherwise lethal attacks with only minor lacerations to the fin. Recent studies have shown that certain tadpoles develop taller fins in the presence of predators. This developmental plasticity is consistent with the tail fin acting as a protective but expendable 'wrap' around the core muscle tissue.

Test of Strain-Time Correspondence Principle with Gel-Containing Elastomers

1986 ◽  
Vol 59 (2) ◽  
pp. 305-314 ◽  
Author(s):  
N. Nakajima ◽  
E. R. Harrell
Keyword(s):  
Large Deformation ◽  
Correspondence Principle ◽  
Small Deformation ◽  
Complex Viscosity ◽  
Shear Stresses ◽  
Growth Data ◽  
Stress Growth ◽  
Linear Viscoelastic ◽  
The Difference ◽  
Linear Viscoelastic Theory

Abstract With four NBR samples and one EPR, oscillatory measurements and stress-growth measurements were performed, the former being at very small deformation and the latter leading to large deformation. The Rheometrics mechanical spectrometer was used with a cone-plate fixture. The temperature was 100°C. The stress-growth data of NBR's, converted to complex viscosity-frequency data through the application of stress-time correspondence principle, were in good agreement with those observed in the oscillatory measurement. Thus, the stress-growth data including the large deformation were “linearized” to form a master curve. With the EPR sample, such a linearization was not necessary. The stress-growth data were adequately treated with the linear viscoelastic theory up to shear stresses approaching the steady state. The difference in behavior between the NBR's and EPR is caused by differences in type and extent of long branching and gel present in the samples.

Stress Corrosion Cracking Behaviour of Flux Bounded TIG Welded AA2219 T87 Aluminum Alloy in 3.5 Weight Percent NaCl Solution

2015 ◽  
Vol 766-767 ◽  
pp. 733-738
Author(s):  
A.V. Santhana Babu ◽  
P.K. Giridharan ◽  
A. Venugopal ◽  
P. Ramesh Narayanan ◽  
S.V.S. Narayana Murty
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Weight Percent ◽  
Corrosion Cracking ◽  
Slow Strain Rate Test ◽  
Nacl Solution ◽  
Test Technique ◽  
Rate Test

Limitation in penetration depth is a concern in conventional TIG welding. To improve penetration capability of TIG process, Flux Bounded TIG (FBTIG) has been developed. Stress corrosion cracking (SCC) behavior of FBTIG welds of aluminum alloy AA 2219 T87 is evaluated in 3.5 weight percent NaCl solution using Slow Strain Rate Test technique (SSRT) as per ASTM G129. SCC index defined as the ratio of the elongation of tensile tested specimen in NaCl to that of air is taken as a measure of the susceptibility to cracking. Based on the SCC index, it is concluded that the SCC resistance of FBTIG joints are good and comparable to that of conventional TIG welds.

Ductile Failure Predictions for the Three-Point Bending Test of a Complex Geometry Made From Aluminum Alloy

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Petr Kubík ◽  
František Šebek ◽  
Josef Zapletal ◽  
Jindřich Petruška ◽  
Tomáš Návrat
Keyword(s):  
Aluminum Alloy ◽  
Damage Mechanics ◽  
Complex Geometry ◽  
Yield Criterion ◽  
Ductile Failure ◽  
Bending Test ◽  
Random Structure ◽  
Three Point Bending ◽  
Good Ability ◽  
Failure Predictions

Abstract The ductile failure predictions have been an issue in many engineering applications. It begins with a design of machines and tools, continues with an evaluation of manufacturing processes, and last but not least ends with the assessment of various structures. The paper deals with a predictability of used criteria for a random structure of aluminum alloy 2024-T351, which was performed under the conditions of room temperature three-point bending. The bi-failure mode creates a space for the numerical studies of various approaches and gives an insight into the model performance. The plasticity was described by Lode-dependent yield criterion, which was coupled with several pressure and Lode-dependent fracture models to form a continuum damage mechanics approach via the material weakening. It was incorporated through a nonlinear damage accumulation, which was finally implemented using Fortran 77 subroutine into abaqus/explicit. All the models exhibited a good ability of crack onset prediction in terms of the force responses and realistic predictability of the crack propagation. The field of deformations was successfully compared with experimental data obtained by an optical method.

Sign in / Sign up

Export Citation Format

Share Document