scholarly journals Modeling Stress-Dependent Anisotropic Elastoplastic Unbound Granular Base in Flexible Pavements

2018 ◽  
Vol 2672 (52) ◽  
pp. 46-56 ◽  
Author(s):  
Yuqing Zhang ◽  
Fan Gu ◽  
Xue Luo ◽  
Bjorn Birgisson ◽  
Robert L. Lytton
Keyword(s):  
Stress Responses ◽  
Compressive Strain ◽  
Flexible Pavements ◽  
Plastic Behavior ◽  
Elastic Model ◽  
Nonlinear Stress ◽  
Anisotropic Elastic ◽  
Base Course ◽  
Granular Base ◽  
Stress Dependent

Unbound granular base (UGB) has a cross-anisotropic and nonlinear (stress-dependent) modulus with a plastic behavior. Existing UGB models address nonlinear cross-anisotropy and plasticity separately. It is unknown how the two characteristics are coupled into a finite element model (FEM) and how this will affect the pavement responses. This study presents a coupled nonlinear cross-anisotropic elastoplastic (NAEP) constitutive model for the UGB and implements it in a weak form equation-based FEM. No material subroutine is needed to address the circular dependence between the stress-dependent anisotropic modulus, structural stress responses, and elastoplastic deformation. The NAEP model was calibrated by triaxial resilient modulus and strength tests and validated using laboratory measurements in a large-scale soil-tank pavement structural test. It is found that the NAEP model is valid and effective in predicting the UGB responses in flexible pavements. The model predicted less horizontal tensile stresses at the base bottom and introduced compressive stresses in the middle and top of the base course. This is caused by an increasing confinement resulting from a horizontal plastic dilation in the base course, which cannot be modeled without considering plasticity. The stress-dependent modulus for the UGB material decreases with depth and the distance from loading centerline. Compared with a nonlinear anisotropic elastic model, the NAEP model predicted the same tensile strain at asphalt layer bottom, a higher base modulus, and a higher subgrade compressive strain. Thus, the nonlinear anisotropic elastic UGB model results in the same fatigue life as the NAEP model but may riskily under-predict rutting damage.

scholarly journals Contrasting roles of GmNAC065 and GmNAC085 in natural senescence, plant development, multiple stresses and cell death responses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bruno Paes Melo ◽  
Isabela Tristan Lourenço-Tessutti ◽  
Otto Teixeira Fraga ◽  
Luanna Bezerra Pinheiro ◽  
Camila Barrozo de Jesus Lins ◽  
...  
Keyword(s):  
Cell Death ◽  
Plant Development ◽  
Stress Responses ◽  
Regulatory Networks ◽  
Lower Stress ◽  
Multiple Stresses ◽  
Gene Sets ◽  
Ros Accumulation ◽  
Stress Dependent ◽  
Senescence Associated Genes

AbstractNACs are plant-specific transcription factors involved in controlling plant development, stress responses, and senescence. As senescence-associated genes (SAGs), NACs integrate age- and stress-dependent pathways that converge to programmed cell death (PCD). In Arabidopsis, NAC-SAGs belong to well-characterized regulatory networks, poorly understood in soybean. Here, we interrogated the soybean genome and provided a comprehensive analysis of senescence-associated Glycine max (Gm) NACs. To functionally examine GmNAC-SAGs, we selected GmNAC065, a putative ortholog of Arabidopsis ANAC083/VNI2 SAG, and the cell death-promoting GmNAC085, an ANAC072 SAG putative ortholog, for analyses. Expression analysis of GmNAC065 and GmNAC085 in soybean demonstrated (i) these cell death-promoting GmNACs display contrasting expression changes during age- and stress-induced senescence; (ii) they are co-expressed with functionally different gene sets involved in stress and PCD, and (iii) are differentially induced by PCD inducers. Furthermore, we demonstrated GmNAC065 expression delays senescence in Arabidopsis, a phenotype associated with enhanced oxidative performance under multiple stresses, higher chlorophyll, carotenoid and sugar contents, and lower stress-induced PCD compared to wild-type. In contrast, GmNAC085 accelerated stress-induced senescence, causing enhanced chlorophyll loss, ROS accumulation and cell death, decreased antioxidative system expression and activity. Accordingly, GmNAC065 and GmNAC085 targeted functionally contrasting sets of downstream AtSAGs, further indicating that GmNAC85 and GmNAC065 regulators function inversely in developmental and environmental PCD.

scholarly journals EFFECTS OF FREEZE-THAWING ON BEARING CAPACITY OF GRANULAR BASE COURSE MATERIAL

2012 ◽  
Vol 68 (3) ◽  
pp. I_115-I_122
Author(s):  
Shinichiro KAWABATA ◽  
Tatsuya ISHIKAWA ◽  
Takumi MURAYAMA ◽  
Shuichi KAMEYAMA
Keyword(s):  
Bearing Capacity ◽  
Base Course Material ◽  
Course Material ◽  
Base Course ◽  
Granular Base

scholarly journals Effects of Freeze-thaw History on Bearing Capacity of Granular Base Course Materials

2016 ◽  
Vol 143 ◽  
pp. 828-835 ◽  
Author(s):  
Shinichiro Kawabata ◽  
Tatsuya Ishikawa ◽  
Shuichi Kameyama
Keyword(s):  
Bearing Capacity ◽  
Freeze Thaw ◽  
Course Materials ◽  
Base Course ◽  
Granular Base

scholarly journals Characterization of Brassica rapa RAP2.4-Related Proteins in Stress Response and as CUL3-Dependent E3 Ligase Substrates

Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 336 ◽  
Author(s):  
Sutton Mooney ◽  
Raed Al-Saharin ◽  
Christina M. Choi ◽  
Kyle Tucker ◽  
Chase Beathard ◽  
...  
Keyword(s):  
Brassica Rapa ◽  
Stress Responses ◽  
Expression Patterns ◽  
Economic Value ◽  
E3 Ligase ◽  
26S Proteasome ◽  
Dependent Manner ◽  
E3 Ligases ◽  
Subsequent Degradation ◽  
Stress Dependent

The turnip Brassica rapa has important economic value and represents a good model system to study gene function in crop plants. ERF/AP2 transcription factors are a major group of proteins that are often involved in regulating stress-responses and developmental programs. Some ERF/AP2 proteins are targets of CULLIN3-based E3 ligases that use BTB/POZ-MATH proteins as substrate receptors. These receptors bind the transcription factor and facilitate their ubiquitylation and subsequent degradation via the 26S proteasome. Here, we show tissue and stress-dependent expression patterns for three Brassica rapa ERF/AP2 proteins that are closely related to Arabidopsis thaliana AtRAP2.4. Cloning of the Brassica genes showed that the corresponding proteins can assemble with a BPM protein and CULLIN3, and that they are instable in a 26S proteasome dependent manner. This work demonstrates the conserved nature of the ERF/AP2-CULLIN3-based E3 ligase interplay, and represents a first step to analyze their function in a commercially relevant crop plant.

scholarly journals STUDY ON NONLINEAR PAVEMENT RESPONSES OF LOW VOLUME ROADWAYS SUBJECT TO MULTIPLE WHEEL LOADS / NETIESINĖS KELIO DANGOS PRIKLAUSOMYBĖS NUO MAŽO INTENSYVUMO KELIŲ, VEIKIAMŲ DAUGKARTINĖMIS RATŲ APKROVOMIS, TYRIMAS

2011 ◽  
Vol 17 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Minkwan Kim ◽  
Joo Hyoung Lee
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Asphalt Pavement ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Element Analysis ◽  
Nonlinear Stress ◽  
Low Volume ◽  
Stress Dependent

This paper describes numerical analyses on low volume roads (LVRs) using a nonlinear three-dimensional (3D) finite element model (FEM). Various pavement scenarios are analyzed to investigate the effects of pavement layer thicknesses, traffic loads, and material properties on pavement responses, such as surface deflection and subgrade strain. Each scenario incorporates a different combination of wheel/axle configurations and pavement geomaterial properties to analyze the nonlinear behavior of thinly surfaced asphalt pavement. In this numerical study, nonlinear stress-dependent models are employed in the base and subgrade layers to properly characterize pavement geomaterial behavior. Finite element analysis results are then described in terms of the effects of the asphalt pavement thickness, wheel/axle configurations, and geomaterial properties on critical pavement responses. Conclusions are drawn by the comparison of the nonlinear pavement responses in the base and subgrade in association with the effects of multiple wheel/axle load interactions. Santrauka Straipsnyje aprašoma skaitinė mažo intensyvumo kelių analizė, taikant netiesinį—erdvinį baigtinių elementų modelį. Skirtingi dangų paviršiaus variantai analizuojami siekiant ištirti, kokiąįtaką kelio dangos elgsenai, t. y. poslinkiams ir kelio pagrindo deformacijoms, turi dangų sluoksnių storiai, eismo apkrovos ir medžiagų savybės. Kiekvienas kelio dangos variantas turi skirtingas ratų arba ašies ir geometrinių savybių formas, kad būtų galima išanalizuoti netiesinę plonos asfalto dangos paviršiaus elgseną. Šioje skaitinėje analizėje nagrinėjami netiesiniai įtempių modeliai, kurie buvo taikomi pagrindo sluoksniams, siekiant tinkamai apibūdinti geometrinę kelio dangos elgseną. Baigtinių elementų analizės rezultatai toliau nagrinėjami atsižvelgiant į asfalto dangos storį ar ašies formą ir geometrines savybes, priklausomai nuo kritinės kelio dangos būklės. Išvados buvo gautos lyginant netiesines kelių dangos priklausomybes pagrindo sluoksnyje, atsižvelgiant į jų sąveiką su daugkartine ratų apkrova.

Development and Finite Element Implementation of Stress-Dependent Elastoviscoplastic Constitutive Model with Damage for Asphalt

2003 ◽  
Vol 1832 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Andrew C. Collop ◽  
A. (Tom) Scarpas ◽  
Cor Kasbergen ◽  
Arian de Bondt
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Compressive Strain ◽  
Local Strain ◽  
Continuum Damage Mechanics ◽  
Dependent Case ◽  
Strain Compatibility ◽  
Incremental Formulation ◽  
Stress Dependent

The development and finite element (FE) implementation of a stress-dependent elastoviscoplastic constitutive model with damage for asphalt is described. The model includes elastic, delayed elastic, and viscoplastic components. The strains (and strain rates) for each component are additive, whereas they share the same stress (i.e., a series model). This formulation was used so that a stress-based nonlinearity and sensitivity to confinement could be introduced into the viscoplastic component without affecting the behavior of the elastic and delayed elastic components. A simple continuum damage mechanics formulation is introduced into the viscoplastic component to account for the effects of cumulative damage on the viscoplastic response of the material. The model is implemented in an incremental formulation into the CAPA-3D FE program developed at Delft University of Technology in the Netherlands. A local strain compatibility condition is utilized such that the incremental stresses are determined explicitly from the incremental strains at each integration point. The model is demonstrated by investigating the response of a semirigid industrial pavement structure subjected to container loading. Results show that the permanent vertical strains in the non-stress-dependent case are significantly lower than the permanent vertical strains in the stress-dependent case. Results also show that in the stress-dependent case, there is a more localized area of high permanent vertical compressive strain directly under the load at approximately halfdepth in the asphalt compared with the non-stress-dependent case, in which the distribution is more even.

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