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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
661

Numerical investigation to determine the development of tensile strength in the early age of concrete using experimental data from anchor pull-out tests

Pan, Zengrui 18 October 2023 (has links)
This study investigates the tensile behavior of anchor pull-out tests from super early age concrete(less than 12h) by finite element(FE) software ANSYS Workbench. In previous experiment, several series of pull-out tests were finished and analyzed. In each per hour, different speeds(1mm/s, 0.2mm/s, 0.1mm/s and 0.833mm/s) were evaluated, getting the results about correlation of pull-out force and displacement(F-D curve). It is difficult to evaluate the specific development of tensile strength in super young concrete, due to the super plasticity that makes itself soft and unstable. The first step of this study is to collect relevant empirical formula, theoretical varying material properties with time and pull-out force of experimental applied anchors. Comparison of simulation analysis results and empirical formulas determines whether the establishment of the finite element model and adapted constitutive model of known natural hardened concrete(NHC) are valid or not. The second procedure is that the material properties of NHC are replaced by different age values and modified until getting the same simulation results as experiment outcome. The propose of this paper is to investigate a more accurate modified formula to describe the development of tensile behavior in super early age concrete:1. Introduction 2. Background 2.1 Modes of failure 2.2 A new failure mode 2.3 Finite Element Numerical Simulation 3. Research Questions 4. Aims/Objectives of the Research 5. Proposed Research Method 5.1 Previous Empirical theory 5.1.1 Cubic Compressive strength of Early Age Concrete 5.1.2 Tensile Strength of Early Age Concrete 5.1.3 Modulus of Elasticity in Early Age Concrete 5.1.4 Prediction of pull-out maximum force to headed studs from concrete 5.2 Pervious Experiment 5.3 Numerical Simulation 6. Significance/Contribution to the Discipline 7. Experiment Program 7.1 Experiment Setup 7.2 Experiment Result 8. Numerical simulation and analysis 8.1 Material Properties 8.2 Modelling Setup 8.3 The first pull-out test 8.4 Comparison Results at different stages 9. Discussion and Results 10. Summary and Conclusion 11. Recommendation for future studies 12. References 13. Appendix
662

Relaxation of PET Orientation at Temperatures Below the Glass Transition

Johnson, Brian Michael January 2013 (has links)
No description available.
663

Effect of Raster Orientation on the Structural Properties of Components Fabricated by Fused Deposition Modeling

Kay, Ryan 05 September 2014 (has links)
No description available.
664

Predictive Modeling For Rate Dependent Toughened-Adhesive Behavior During Impact

Bas, Gamze S. January 2017 (has links)
No description available.
665

Sensitization Effects on Environmentally Assisted Cracking of Al-Mg Naval Alloys

Seifi, Mohsen January 2015 (has links)
No description available.
666

Use Of Fly Ash As Eco-Friendly Filler In Synthetic Rubber For Tire Applications

Ren, Xianjie, ren 10 June 2016 (has links)
No description available.
667

Uniaxial Tensile and Creep Behavior of Omnisil Membranes in Membrane Based Wet Electrostatic Precipitator

Valavala, Pavan Kumar January 2005 (has links)
No description available.
668

Load Response Analysis of the WAY-30 Test Pavements: US Route 30, Wayne County, Ohio

Romanello, Michael T. January 2007 (has links)
No description available.
669

Evaluation of the Response of Perpetual Pavement at Accelerated Pavement Loading Facility: Finite Element Analysis and Experimental Investigation

Hernandez, Jaime A. 22 September 2010 (has links)
No description available.
670

Mechanical Properties of Calcium Phosphate and Additively Manufactured Titanium Alloy for Composite Spinal Implants / Mekaniska egenskaper hos kalciumfosfat och additivt tillverkad titanlegering förkomposit-ryggimplantat

Lantz, Josephine January 2021 (has links)
One of the major health problems in western societies is back pain, with a prevalence rate of 49%–80%. In many cases, the back pain is due to degenerated discs. The gold standard to treat a severely degenerated disc is spinal fusion, where the vertebral disc is replaced with a cage structure. However, fusion cages have a failure rate of 30%, hence the need for further development. The focus of this thesis is to evaluate the combination of calcium phosphate cement with titanium, for a spinal application. Mechanical tests in the form of tensile, compression and 4-point-bending were performed to study the different material properties. The obtained results was applied as material parameters for isotropic linear elastic material models, using ANSYS. This was then used to develop a cage design through topology optimisation which was further evaluated by using Finite Element Analysis. From the tensile testing of the titanium, isotropic behaviour was found. It was also found that a longer mixing time of the cement resulted in poorer mechanical properties of the calcium phosphate, however, no conclusive results were obtained from the 4-point-bending tests. The final cage geometry filled with calcium phosphate was tested under compression to see whether the cage could protect the calcium phosphate or not. MicroCT after the test confirmed that no larger cracks developed during the testing, suggesting that the cage is strong enough to protect the calcium phosphate from mechanical failure.

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