scholarly journals Master Function for Analytical Determination of the Interlayer Bond Shear Stiffness and Fatigue Functions for Asphalt Pavements

2018 ◽  
Vol 251 ◽  
pp. 01001
Author(s):  
Borislav Hristov
Keyword(s):  
Fatigue Testing ◽  
Shear Stiffness ◽  
Computational Design ◽  
Asphalt Pavements ◽  
Analytical Determination ◽  
Sigmoid Function ◽  
Finite Element Program ◽  
Cyclic Shear ◽  
Master Function ◽  
Interlayer Bond

In order to determine the shear stiffness at the interface between asphalt layers and to take into account the interactions of repeated traffic loading, acceleration and braking processes as well as temperature influence, a complicated apparatus for cycling testing of the interlayer bond (CTIB) has been developed. An extensive experimental procedure has been created to include all factors that influence the interlayer bond. Using the experimental results, a master function for the analytical assessment of the shear stiffness has been established. The regression which approximates most accurately the experimentally determined shear stiffness values is the sigmoid function. Through implementation of the master function into a finite element program the fatigue status of asphalt pavements, which is affected by the interlayer bond of different quality, have been calculated over the service life of 30 years using the German method for computational design according to RDO Asphalt 09. The results presented below are based on the results of IGF project “Cyclic Shear Stiffness and Shear Fatigue Testing for Evaluation and Optimization of Interlayer Bond in Asphalt Pavements”, supported by the Association of Industrial Research Communities (AIF) of the German Asphalt Institute (DAI) in cooperation with TU Braunschweig.

Stress–strain pattern–based criterion to assess cyclic shear resistance of soil from laboratory element tests

2016 ◽  
Vol 53 (9) ◽  
pp. 1460-1473 ◽  
Author(s):  
Dharma Wijewickreme ◽  
Achala Soysa
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Shear Stiffness ◽  
Large Strains ◽  
Fundamental Parameter ◽  
Stress Strain ◽  
Cyclic Shear ◽  
Excess Pore Water Pressure ◽  
Excess Pore

The cyclic shear response of soils is commonly examined using undrained (or constant-volume) laboratory element tests conducted using triaxial and direct simple shear (DSS) devices. The cyclic resistance ratio (CRR) from these tests is expressed in terms of the number of cycles of loading to reach unacceptable performance that is defined in terms of the attainment of a certain excess pore-water pressure and (or) strain level. While strain accumulation is generally commensurate with excess pore-water pressure, the definition of unacceptable performance in laboratory tests based purely on cyclic strain criteria is not robust. The shear stiffness is a more fundamental parameter in describing engineering performance than the excess pore-water pressure alone or shear strain alone; so far, no criterion has considered shear stiffness to determine CRR. Data from cyclic DSS tests indicate consistent differences inherent in the patterns between the stress–strain loops at initial and later stages of cyclic loading; instead of relatively “smooth” stress–strain loops in the initial parts of loading, nonsmooth changes in incremental stiffness showing “kinks” are notable in the stress–strain loops at large strains. The point of pattern change in a stress–strain loop provides a meaningful basis to determine the CRR (based on unacceptable performance) in cyclic shear tests.

A Comparative Study of the Response of Double Shearing and Hypoplastic Models

2002 ◽  
Author(s):  
Huaning Zhu ◽  
Morteza M. Mehrabadi ◽  
Mehrdad Massoudi
Keyword(s):  
Cyclic Loading ◽  
Mechanical Response ◽  
Constitutive Relations ◽  
Constitutive Models ◽  
Shear Loading ◽  
Biaxial Compression ◽  
Finite Element Program ◽  
Cyclic Shear ◽  
Hypoplastic Model ◽  
Element Program

The principal objective of this paper is to compare the mechanical response of a double shearing model with that of a hypoplastic model under biaxial compression and under cyclic shear loading. As the origins and nature of these two models are completely different, it is interesting to compare the predictions of these two models. The constitutive relations of the double shearing and the hypoplastic models are implemented in the finite element program ABACUS/Explicit. It is found that the hypoplastic and the double shearing constitutive models both show strong capability in capturing the essential behavior of granular materials. In particular, under the condition of non-cyclic loading, the stress ratio and void ratio predictions of the double shearing and the hypoplastic models are relatively close, while under the condition of cyclic loading, the predictions of these models are quite different. It is important to note that in the double shearing model employed in this comparison the shear rates on the two slip systems are assumed to be equal. Hence, the conclusions derived in this comparison pertain only to this particular double shearing model. Similarly, the hypoplasticity model considered here is that proposed by Wu, et al. [30] and the conclusions reached here pertain only to this particular hypoplasticity model.

Cyclic shear response of additively manufactured Inconel 718

2020 ◽  
Vol 26 (7) ◽  
pp. 1237-1248
Author(s):  
Sanna F. Siddiqui ◽  
Ali P. Gordon
Keyword(s):  
Inconel 718 ◽  
Fatigue Testing ◽  
Current Trend ◽  
Transversely Isotropic ◽  
Content Type ◽  
Shear Moduli ◽  
Cyclic Shear ◽  
Cyclic Response ◽  
Torsional Fatigue ◽  
The Impact

Purpose Additive manufacturing (AM) studies on Inconel 718 (IN718) have focused on exploring its tensile and fatigue response. As IN718 is used in the propulsion and energy sector, the impact of shearing is also critical to ensuring the durability of these components. As such, this study aims to explore the relation between build orientation on the shear cyclic response of direct metal laser sintered (DMLS) IN718. Design/methodology/approach IN718 torsion specimens were manufactured along six build orientations: (100)-X, (010)-Y, (001)-Z, (110)-XY45, (101)-XZ45 and (011)-YZ45, using the DMLS process. Torsional fatigue testing was performed on as-built specimens, from which fracture behavior, surface roughness, softening/hardening response and monotonic/cyclic shear torsional properties were assessed. Findings DMLS IN718 was found to exhibit transversely isotropic behavior. In terms of shear stress range and shear modulus, Z > (X, XY45, Y) > (XZ45, YZ45). Specimens cyclically hardened to stabilization and softened to fracture. In terms of torsional fatigue fracture response, the Z, XZ45 and YZ45 specimens exhibited crack initiation and propagation from internal defects, whereas cracks were found to initiate at the surface and propagate between and through build layers for the X, Y and XY45 specimens. Originality/value This study reports the torsional cyclic response and shear moduli exhibited by as-built DMLS IN718 manufactured along varying build orientations. The findings are applicable for researchers because of the wide use of IN718 in the gas turbine industry, and the current trend to replace conventional manufacturing with AM.

scholarly journals Shear-Torque Fatigue Performance of Geogrid-Reinforced Asphalt Interlayers

2020 ◽  
Vol 12 (11) ◽  
pp. 4381
Author(s):  
Davide Ragni ◽  
Francesco Canestrari ◽  
Fatima Allou ◽  
Christophe Petit ◽  
Anne Millien
Keyword(s):  
Glass Fiber ◽  
Fatigue Tests ◽  
Shear Loading ◽  
Fatigue Performance ◽  
Asphalt Pavements ◽  
Test Results ◽  
Cyclic Shear ◽  
Shear Fatigue ◽  
Interesting Correlation ◽  
Valid Solution

Interlayer reinforcement systems represent a valid solution to improve performance and extend the service life of asphalt pavements, reducing maintenance costs. The main issue is that the presence of reinforcement may hinder the full transmission of stresses between asphalt layers, reducing the overall pavement bearing capacity. This study aimed at evaluating the mechanical behavior of geogrid-reinforced asphalt interlayers under cyclic shear loading. To this purpose, a trial section, characterized by three types of interface (reinforced with carbon fiber grid, reinforced with glass fiber grid and unreinforced), was built. Cores were taken from the trial section to carry out shear-torque fatigue tests. Static Leutner shear tests were also performed on cored specimens having the same interface configuration. From data gathered in the present study, shear-torque fatigue tests have proved to be a powerful tool for investigating reinforced specimens. Results clearly ranked the investigated materials, showing that the glass fiber grid has the lowest shear fatigue performance in comparison with the other two interfaces at 20 °C. However, the shear fatigue resistance of glass fiber grid increases significantly at 10 °C. Finally, an interesting correlation was found between cyclic and static shear test results that should be better investigated in future studies.

An Experimental and Modeling Study of Thermal Cyclic Behavior of Sn-Cu and Sn-Pb Solder Joints

1993 ◽  
Vol 323 ◽  
Author(s):  
Y.-H. Pao ◽  
S. Badgley ◽  
R. Govila ◽  
E. Jah
Keyword(s):  
Solder Joints ◽  
Cyclic Behavior ◽  
Temperature Cycle ◽  
Beam Specimen ◽  
Finite Element Program ◽  
Creep Properties ◽  
Cyclic Shear ◽  
Double Beam ◽  
Element Program ◽  
Hysteresis Response

AbstractThermal cyclic shear stress/strain hysteresis response of 97Sn-2Cu-0.8Sb-0.2Ag, 95.5Sn-4Cu-0.5Ag, 63Sn-37Pb, and 62Sn-36Pb-2Ag solder joints have been determined using a double beam specimen. The temperature cycle had a period of 40 minutes and extreme temperatures of 40°C and 140°C.The steady state creep properties of these solders were determined, and the associated Norton's law was implemented in a finite element program to simulate the experiment. The fatigue life of these solders joints and failure mechanism are also discussed.

InSiSST™ – An Advanced In-Situ Facility for Measuring Shear Stiffness of Asphalt Pavements

2020 ◽  
pp. 851-863
Author(s):  
S.N. Goodman ◽  
W. Bekheet ◽  
Y. Hassan ◽  
A.O. Abd El Halim ◽  
J. Ponniah
Keyword(s):  
Shear Stiffness ◽  
Asphalt Pavements

Constitutive Behavior and Low Cycle Thermal Fatigue of 97Sn-3Cu Solder Joints

1993 ◽  
Vol 115 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Y.-H. Pao ◽  
S. Badgley ◽  
E. Jih ◽  
R. Govila ◽  
J. Browning
Keyword(s):  
Steady State ◽  
Constitutive Equation ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Steady State Creep ◽  
Creep Mechanism ◽  
Beam Specimen ◽  
Finite Element Program ◽  
Cyclic Shear ◽  
Element Program

The thermal cyclic shear stress/strain hysteresis response and associated steady-state creep parameters of 97Sn-3Cu solder joints have been determined using a beam specimen previously developed by Pao et al. (1992a). The solder joint was subjected to a 40-minute thermal cycling from 40°C to 140°C. A constitutive equation based on elastic and steady-state creep deformation for the solder has been formulated and implemented in a finite element program, ABAQUS, to model the experiment. The results show that the constitutive equation based on one single creep mechanism cannot fully account for the deformation during cooling, as opposed to the case of 90Pb-10Sn where the entire cyclic deformation can be well modeled by a similar constitutive equation (Pao et al., 1992c). This suggests that another creep mechanism is dominant for lower stresses and higher temperature. The thermal fatigue results show that the failure mechanism of 97Sn-3Cu joints is similar to that of 90Pb-10Sn joints, but the number of cycles to failure of 97Sn-Cu solder joints is at least 5 times longer than 90Pb-10Sn solder joints. This indicates the potential application of 97Sn-3Cu in place of 90Pb-10Sn solder.

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