Joseph F. Labuz
University of Minnesota
Ultimate tensile strengthDigital image correlationGeologyEngineeringBrittlenessComposite materialAcoustic emissionGeotechnical engineeringMaterials scienceStiffnessSofteningPlane stressLateral earth pressureFracture (geology)MechanicsFracture mechanicsStructural engineeringStress (mechanics)Shear (geology)Rock mechanics
Publications 189
#1Xinjun LiH-Index: 14
#2Mihai MarasteanuH-Index: 33
Last. R. Christopher Williams (Iowa State University)H-Index: 22
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This paper investigates the effect of loading level and loading rate on the damage development and strength of asphalt mixtures. Indirect tensile creep tests with different loading levels and strength tests with three loading rates were performed at three low temperatures for ten mixtures. An acoustic emission (AE) system with eight recording channels was used to monitor the development of micro cracking in the specimens for both tests for one mixture. The experimental results show that test tem...
#1Qing Lin (PKU: Peking University)H-Index: 11
#2Joseph F. LabuzH-Index: 32
2 Citations
#1C. S. Kao (UMN: University of Minnesota)H-Index: 6
#2Fernanda C.S. Carvalho (UMN: University of Minnesota)H-Index: 5
Last. Joseph F. Labuz (UMN: University of Minnesota)H-Index: 32
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Abstract Acoustic emission (AE) events were located and characterized from a mode I fracture test on Charcoal granite. An AE source was modeled as a displacement discontinuity, a microcrack, with a displacement vector b , normal n , and area Δ A . For convenience, the source parameters were recovered through a moment tensor representation, the components of which were estimated by minimizing the error between theoretical and measured displacements at sensor positions, with an appropriate constra...
40 CitationsSource
#1Igor Ostanin (UMN: University of Minnesota)H-Index: 8
#2Sofia G. Mogilevskaya (UMN: University of Minnesota)H-Index: 23
Last. John Napier (University of the Witwatersrand)H-Index: 2
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The direct formulation of the complex variables boundary element method is generalized to allow for solving problems with constant body forces. The hypersingular integral equation for two-dimensional piecewise homogeneous medium is presented and the numerical solution is described. The technique can be used to solve a wide variety of problems in engineering. Several examples are presented to verify the approach and to demonstrate its key features. The results of calculations performed with the p...
9 CitationsSource
#1Luigi Biolzi (Polytechnic University of Milan)H-Index: 26
#2Joseph F. LabuzH-Index: 32
Last. Giovanni Muciaccia (Polytechnic University of Milan)H-Index: 7
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Abstract Pre-existing inhomogeneities such as micropores and microcracks dictate the mechanical and physical properties of rock. Overloading, weathering, changing temperatures, and exceptional events can increase this damage, usually by microcracking, and as a consequence, modify the effective properties of the rock. To examine the problem of a structure composed of rock with various stages of damage, three point bending tests on sandstone specimens exposed to elevated temperatures are presented...
17 CitationsSource
The output from an earth pressure cell (EPC) is usually related to the normal stress in soil through fluid calibration, where a known pressure is applied to the EPC and the output is recorded. However, distribution of normal stress within a soil is not uniform, and the EPC is not an ideal membrane—bending stiffness affects the response. These factors complicate the performance of the EPC. A calibration procedure for an EPC is reviewed, and it is shown that these controversial sensors can provide...
13 CitationsSource
#1Richard WanH-Index: 1
#2Mustafa AlsalehH-Index: 1
Last. Joseph F. LabuzH-Index: 32
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Failure in granular materials: macro and micro views.- Instability in Loose Sand: Experimental Results and Numerical Simulations with a Microstructural Model.-Failure in granular materials in relation to material instability, fabric and plastic flow issues.-Loss of controllability in partially saturated soils.- Critical plane approach to analysis of failure criteria for anisotropic geomaterials.-A simple method to consider density and bonding effects in modeling of geomaterials.-Cyclic mobility ...
6 CitationsSource
#1C. S. Kao (UMN: University of Minnesota)H-Index: 6
#2Joseph F. Labuz (UMN: University of Minnesota)H-Index: 32
Last. Luigi Biolzi (Polytechnic University of Milan)H-Index: 26
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1 Citations
#1Raul Velasquez (UW: University of Wisconsin-Madison)H-Index: 18
#1Raul Velasquez (UW: University of Wisconsin-Madison)H-Index: 9
Last. Mugurel Turos (UMN: University of Minnesota)H-Index: 13
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The feasibility of characterizing asphalt mixtures at low temperatures by means of the Bending Beam Rheometer (BBR) is investigated in this paper. The main difficulty in implementing this test method into current practice is the use of thin beams that may not capture the overall behavior of the actual asphalt pavement. The volume of material tested may not be representative, especially when the asphalt mixtures contained aggregate sizes that are larger than the smallest dimension of the beam. Th...
5 Citations
#1M. Haggerty (UMN: University of Minnesota)H-Index: 3
#2Qing Lin (UMN: University of Minnesota)H-Index: 11
Last. Joseph F. Labuz (UMN: University of Minnesota)H-Index: 32
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The high resolution technique of electronic speckle pattern interferometry (ESPI) can be very useful in determining deformation of laboratory specimens and identifying initiation of failure. The in-plane ESPI theory is described and the fringe pattern of the processed ESPI image is analyzed to determine deformation and crack opening displacement. Fringes on the ESPI image represent lines of equal intensity, which relate to surface displacement. An ESPI system was constructed and calibrated for m...
21 CitationsSource