Using Genetic Programming to Predict Plastic Strain in Subgrade Soils Under Repeated Loading

2016 ◽  
Vol 45 (1) ◽  
pp. 20160128 ◽  
Author(s):  
S.-R. Yang ◽  
J.-R. Chang
Keyword(s):  
Plastic Strain ◽  
Genetic Programming ◽  
Repeated Loading ◽  
Subgrade Soils

Model for Resilient Modulus and Permanent Strain of Subgrade Soils

1998 ◽  
Vol 1619 (1) ◽  
pp. 85-93 ◽  
Author(s):  
A.S. Muhanna ◽  
M.S. Rahman ◽  
P.C. Lambe
Keyword(s):  
Simple Model ◽  
Plastic Strain ◽  
Confidence Intervals ◽  
Empirical Model ◽  
Resilient Modulus ◽  
Cohesive Soil ◽  
Repeated Loading ◽  
Subgrade Soils ◽  
Permanent Strain ◽  
Proposed Model

The resilient modulus and cumulative permanent strain of subgrade soils under anticipated repeated loading are important considerations for the design of a pavement against fatigue and rutting failures. A simple model was developed to evaluate the resilient modulus and accumulated permanent strain of cohesive subgrade soils under repeated loads. The empirical model was derived from the observed behavior of an A-6 cohesive soil. The model was tested against an A-5 soil. The proposed model was found to predict adequately the resilient modulus and the accumulated plastic strain for all A-6 and A-5 specimens with 90 percent confidence intervals of 0.61 and 1.4, and 0.66 and 1.39, respectively.

Creep and Long-Term Strength of Molybdenum Alloy

2016 ◽  
Vol 843 ◽  
pp. 28-33
Author(s):  
S.P. Samoilov ◽  
A.O. Cherniavsky
Keyword(s):  
Tensile Strength ◽  
Plastic Strain ◽  
Strain Curve ◽  
Type Equation ◽  
Monotonic Loading ◽  
Molybdenum Alloy ◽  
Repeated Loading ◽  
Temperature Application ◽  
Term Creep

Mechanical behavior of a molybdenum alloy for high-temperature application was investigated at monotonic loading up to fracture, stress-and strain-controlled cyclic loading and short-term creep (less than 9 hours) under the temperatures from 293 to 1773 K using Gleeble-3800 physical simulator. The tests show that plastic strain corresponding to the tensile strength of the material under monotonic loading is small enough (<1%) whereas residual plastic strain after fracture exceeds by 50%. Repeated loading decreases the tensile strength and yield stress, but increases stable (rising) part of stress-strain curve. Increase in the test temperature leads to the change in fracture type from ductile to quasi-brittle distributed at a temperature above 1673 K. Under relatively low temperatures the rheological properties of the material depend strongly on the material processing history. Obtained creep data allows putting up a thermo-activational type equation used to calculate the steady creep rate. Coupling with the known Hoff's model for the creep prefracture stage, this equations allow not only strain rate but also adequate estimation of fracture time.

Correlation between Resilient Modulus and Plastic Deformation for Cohesive Subgrade Soil under Repeated Loading

2008 ◽  
Vol 2053 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Shu-Rong Yang ◽  
Wei-Hsing Huang ◽  
Chi-Chou Liao
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Resilient Modulus ◽  
Cohesive Soil ◽  
Repeated Loading ◽  
Hardening Behavior ◽  
Subgrade Soil ◽  
Stress Levels ◽  
Strain Hardening Behavior

Pavement performance is related to resilient modulus and plastic deformation of pavement materials, which in turn are affected by environmental conditions and traffic loading. A series of triaxial tests was conducted on a residual lateritic soil for 10,000 load repetitions, with some specimens subjected to 100,000 load repetitions, to characterize the behavior of cohesive subgrades under repeated loading, including resilient modulus and plastic deformation. The shakedown concept was used to describe the accumulated plastic deformation and the strain-hardening and softening behavior. Experimental results show that the resilient modulus of cohesive subgrades exhibits strain-hardening behavior under low stress levels. In the meantime, the rate of plastic strain accumulation becomes diminutive. Soil under this condition is in a stable state. Conversely, under high stress levels, cohesive soil tends to soften after a specific number of load applications and accumulates excessive plastic strain and leads to an unstable state. To predict the plastic strain of subgrade soil under repetitive loading, regression models incorporating the strain-hardening behavior for a cohesive soil were used.

Using Repeated-Load Triaxial Tests to Evaluate Plastic Strain Potentials in Subgrade Soils

2005 ◽  
Vol 1913 (1) ◽  
pp. 86-98 ◽  
Author(s):  
Anand J. Puppala ◽  
Suppakit Chomtid ◽  
Venkat Bhadriraju
Keyword(s):  
Plastic Strain ◽  
Test Procedure ◽  
Soil Layer ◽  
Silty Sand ◽  
Triaxial Tests ◽  
Plastic Strains ◽  
Plastic Deformations ◽  
Subgrade Soils ◽  
Repeated Load ◽  
Repeated Load Triaxial

The design and the analysis of flexible pavement systems depend on soil layer characterization, traffic loads, and number of passes. The current AASHTO design method for flexible pavements uses resilient characteristics of subsoils to characterize and determine the structural support of each layer and to design the thickness of the layers. This moduli property, however, does not fully account for the plastic strain or rutting potentials of subsoils, as in the cases in which silt and mixed soils undergo high plastic deformations but possess high resilient properties. A study was initiated to establish a test procedure to use a repeated load triaxial device to measure plastic strain potentials of subgrade soils. Laboratory-compacted soil specimens were subjected to a repeated deviatoric load, determined as a percentage of static deviatoric load at failure under un-consolidated undrained conditions. The plastic strains were monitored during 10,000 repeated load cycles, and the accumulated plastic deformations were determined. The test procedure and test results conducted on two types of soils, a coarse sand and silty sand, are presented. Effects of soil type, compaction moisture content, dry unit weight, confining pressure, and deviatoric stresses on the plastic strains were addressed.

Variation of elastic modulus of high strength 21-6-9 tube and its influences on forming quality in numerical control rotary draw bending

2021 ◽  
pp. 095440622199069
Author(s):  
Jun Fang ◽  
Fang Ouyang ◽  
Shiqiang Lu ◽  
Kelu Wang ◽  
Xuguang Min ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Plastic Strain ◽  
High Strength ◽  
Steel Tube ◽  
Numerical Control ◽  
Repeated Loading ◽  
Stainless Steel Tube ◽  
Rotary Draw Bending ◽  
Forming Quality ◽  
Draw Bending

Elastic modulus is one of the most crucial mechanical property parameters that affects the plastic forming quality of bent parts, especially for springback. Elastic modulus practically varies with plastic deformation, and its precise description is necessary to enhance simulation precision for tube bending and gain steady, high-precision bent components by actual bending. Using repeated loading-unloading tensile tests (RLUTTs), the variation of elastic modulus of high strength 21-6-9 stainless steel tube (21-6-9-HS tube) in terms of plastic strain has been obtained, which its decreases rapidly at the beginning, then decreases tardily and tends to be stable in the end with increasing the plastic strain. The variation can be expressed as a first order exponential decay function. By embedding the variation of elastic modulus with the plastic strain into ABAQUS software to simulate numerical control (NC) rotary draw bending of the 21-6-9-HS tube, the prediction precision for the springback angle, springback radius, maximum cross section distortion ratio and maximum wall thinning ratio can be improved by 11.98%, 7.62%, 35.53% and 11.55%, respectively.

scholarly journals Determination of the Resilient modulus MR for the lime stabilized clay obtained from the repeated loading CBR tests

2012 ◽  
Vol 44 (2) ◽  
pp. 143-153 ◽  
Author(s):  
Wojciech Sas ◽  
Andrzej Głuchowski ◽  
Alojzy Szymański
Keyword(s):  
Resilient Modulus ◽  
Back Analysis ◽  
Road Construction ◽  
Repeated Loading ◽  
Recoverable Strain ◽  
Subgrade Soils ◽  
Test Parameters ◽  
Local Soil ◽  
Repeated Test

Abstract Determination of the Resilient modulusMR for the lime stabilized clay obtained from therepeated loading CBR tests. The main aim of this paper is to prove that CBR repeated test is useful to give an adequate like unconfi ned cyclic triaxial test parameters for design the pavement and subgrade soils. That parameter is the Resilient modulus (MR) which is the elastic modulus based on the recoverable strain under repeated load. Resilient modulus (MR), is an important parameter which characterizes the subgrade’s ability to withstand repetitive stresses under traffic loadings. The 1993 AASHTO guide for design of flexible pavements recommends the use of MR. The additional aim is connected with the concept of sustainable development. For many countries, where resources are at premium, it is very important that stabilized local soil can be used for road construction. For ensuring that stabilized clay can be used for pavement material standard compaction, CBR and repeated CBR tests were performed. In that paper parameter MRof the subgrade lime stabilized clay soil by laboratory CBR repeated test were determined using for calculation formulas from triaxial cyclic test. Based on AASHTO empirical equation the static CBR values using back analysis was also calculated. Finally both values of CBR determined and calculated were compared.

EXPERIMENT STUDY ON MECHANICAL PROPERTIES OF GRANITE UNDER REPEATED LOADING AND UNLOADING

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1634-1639 ◽  
Author(s):  
YUN-HUA HU ◽  
QUAN-SHENG LIU
Keyword(s):  
Acoustic Emission ◽  
Plastic Strain ◽  
Axial Stiffness ◽  
Repeated Loading ◽  
Testing System ◽  
Lateral Stiffness ◽  
Internal Damage ◽  
Brittle Rocks ◽  
Loading And Unloading ◽  
Change Trend

Deformation rules and acoustic emission characteristics of granite under repeated loading-unloading are studied using the MTS Mechanics Testing System and Disp. acoustic emission instrument. It's found that the axial stiffness of granite as well as Poisson's ratio increases with the development of the plastic strain while the change trend of lateral stiffness is negative. For brittle rocks, strain is produced by three mechanisms: elastic deformation, axial micro-cracking and compaction. The peak AE rate is increasing with the plastic strain, which indicates that using the axial plastic strain as the internal damage variable to represent rock damage is reasonable.

Resilient Modulus and Plastic Strain of Unsaturated Cohesive Subgrade Soils

2006 ◽  
Author(s):  
Johnson H. S. Kung ◽  
H. D. Lin ◽  
Shu-Jung Yang ◽  
Wei-Hsing Huang
Keyword(s):  
Plastic Strain ◽  
Resilient Modulus ◽  
Subgrade Soils
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