Engineering Commons^™

Finite Element-Based Machine Learning Model For Predicting The Mechanical Properties Of Composite Hydrogels, Yasin Shokrollahi, Pengfei Dong, Peshala T. Gamage, Nashaita Patrawalla, Vipuil Kishore, Hozhabr Mozafari, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

In this study, a finite element (FE)-based machine learning model was developed to predict the mechanical properties of bioglass (BG)-collagen (COL) composite hydrogels. Based on the experimental observation of BG-COL composite hydrogels with scanning electron microscope, 2000 microstructural images with randomly distributed BG particles were created. The BG particles have diameters ranging from 0.5 μm to 1.5 μm and a volume fraction from 17% to 59%. FE simulations of tensile testing were performed for calculating the Young’s modulus and Poisson’s ratio of 2000 microstructures. The microstructural images and the calculated Young’s modulus and Poisson’s ratio by FE simulation were used …

Processing And Mechanical Properties Of Hot-Pressed Zirconium Diboride – Zirconium Carbide Ceramics, Eric W. Neuman, William Fahrenholtz, Gregory E. Hilmas

Materials Science and Engineering Faculty Research & Creative Works

ZrB2 was mixed with 0.5 wt% carbon and up to 10 vol% ZrC and densified by hot-pressing at 2000 °C. All compositions were > 99.8% dense following hot-pressing. The dense ceramics contained 1–1.5 vol% less ZrC than the nominal ZrC addition and had between 0.5 and 1 vol% residual carbon. Grain sizes for the ZrB2 phase decreased from 10.1 µm for 2.5 vol% ZrC to 4.2 µm for 10 vol% ZrC, while the ZrC cluster size increased from 1.3 µm to 2.2 µm over the same composition range. Elastic modulus was ~505 GPa and toughness was ~2.6 MPa·m½ for all compositions. …

Anti-Washout Concrete: An Overview, Hao Lu, Xiao Sun, Hongyan Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Anti-washout concrete (AWC) is a special cement-based material that can be directly employed in underwater environments without dispersion. It was developed around 50 years ago, and more than 150 journal articles and technical reports have been published. This paper provides a holistic review about the basic fresh-state and hardened-state properties of the AWC, such as water (washout) resistance, consistency, bleeding and segregation resistance, mechanical properties, and durability, as well as relevant testing methods. The discrepancies between AWC's characteristics and those of conventional concrete are clearly presented. The mixture compositions, supplementary cementitious materials (SCMs), and other conditions that affect AWC's performance …

Room-Temperature Mechanical Properties Of A High-Entropy Diboride, Alec C. Murchie, Jeremy Lee Watts, William Fahrenholtz, Gregory E. Hilmas

Materials Science and Engineering Faculty Research & Creative Works

The mechanical properties of a (Hf,Mo,Nb,Ta,W,Zr)B2 high-entropy ceramic were measured at room temperature. A two-step synthesis process was utilized to produce the (Hf,Mo,Nb,Ta,W,Zr)B2 ceramics. The process consisted of a boro/carbothermal reduction reaction followed by solid solution formation and densification through spark plasma sintering. Nominally, phase pure (Hf,Mo,Nb,Ta,W,Zr)B2 was sintered to near full density (8.98 g/cm3) at 2000°C. The mean grain size was 6 ± 2 µm with a maximum grain size of 17 µm. Flexural strength was 528 ± 53 MPa, Young's modulus was 520 ± 12 GPa, fracture toughness was 3.9 ± 1.2 MPa·m1/2, and hardness (HV0.2) was 33.1 …

Use Of Saturated Lightweight Sand To Improve The Mechanical And Microstructural Properties Of Uhpc With Fiber Alignment, Huanghuang Huang, Le Teng, Xiaojian Gao, Kamal Khayat, Fazhou Wang, Zhichao Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper studied the influence of pre-saturated lightweight sand (LWS) on the mechanical and microstructural properties of UHPC cast with steel fiber alignment. The changes in hydration kinetics, porosity, nano-mechanical, and mechanical properties were studied. The LWS was used at 0–50% replacement volumes of total sand. Predominant fiber alignment was favored through a flow-induced casting method during casting of flexural prisms. Experiment results showed that the 28-d autogenous shrinkage was decreased from 450 to 275 μm/m with the LWS content increasing from 0 to 50%. The addition of 20% LWS led to maximum increases of 15%, 15%, and 20% in …

Development And Characterization Of Magnesium Phosphate Cement Based Ultra-High Performance Concrete, Jihui Qin, Fumin Dai, Hongyan Ma, Xiaobing Dai, Zhen Li, Xingwen Jia, Jueshi Qian

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study aims at the development of magnesium phosphate cement-based ultra-high performance concrete (MPC-UHPC). To this end, MPC paste phase was designed by using high magnesia-to-phosphate (M/P, 3.5) and low water-to-cement (W/C, 0.10–0.16) mass ratios, and certain amounts of ultra-fine fly ash (UFA, 5%–15%). Fresh and hardened properties, and microstructure of the developed MPC-UHPC were evaluated, and compared with those of conventional UHPC as well. Test results showed that lower W/C resulted in higher mechanical strengths and lower drying shrinkage, but the sharp decrease of workability and increase of autogenous shrinkage. At a constant W/C, the addition of UFA effectively …

Development Of The Uhpc Mix For 3d Printing, Buse Ilayda Oz

FIU Electronic Theses and Dissertations

This thesis utilizes the development of Ultra-High-Performance Concrete mix design for 3-Dimensional (3D) Printing purposes. 3D concrete printing offers many advantages such as the improvements in safety, quality, and productivity. Moreover, it holds a great advantage for the construction of structural elements that are difficult to construct by conventional methods. These advantages carry a huge potential for solving the aforementioned challenges.

Seven UHPC mixes have been designed and analyzed using various test setups for comparison purposes. Extrudability, flowability, buildability, and open time were measured using the fresh properties of the UHPC mixes. Mechanical properties were measured using compression test setups. …

Evaluation Of Microstructural And Mechanical Behavior Of Ahss Cp780 Steel Welded By Gmaw-Pulsed And Gmaw-Pulsed-Brazing Processes, Alan Jadir Romero-Orozco, Jaime Taha-Tijerina, Rene De Luna-Alanis, Victor Hugo Lopez-Morelos, Maria Del Carmen Ramirez, Melchor Salazar-Martinez, Francisco Fernando Curiel-Lopez

Manufacturing & Industrial Engineering Faculty Publications and Presentations

Joints of complex phase 780 (CP-780) advanced high strength steel (AHSS) were carried out by using an ER-CuAl-A2 filler metal for the gas metal arc welding pulsed brazing (GMAW-P- brazing) process and the ER-80S-D2 for the GMAW-P process employing two levels of heat input. The phases in the weld bead and HAZ were analyzed, and the evaporation of zinc by means of scanning electron microscopy (SEM) was also monitored. The mechanical properties of the welded joints were evaluated by tension, microhardness and vertical impact tests. It was found that there was greater surface Zn evaporation in the joints welded with …

Elimination Of Extraordinarily High Cracking Susceptibility Of Aluminum Alloy Fabricated By Laser Powder Bed Fusion, Holden Hyer, Le Zhou, Sharon Park, Thinh Huynh, Abhishek Mehta, Saket Thapliyal, Rajiv S. Mishra, Yongho Sohn

Mechanical Engineering Faculty Research and Publications

Using the calculation of phase diagrams approach and Scheil solidification modeling, the Al-2.5Mg-1.0Ni-0.4Sc-0.1Zr alloy was designed, intentionally with an extraordinarily high cracking susceptibility, making it prime for solidification cracking during laser powder bed fusion. This study demonstrates the ability to mitigate even the most extreme solidification cracking tendencies in aluminum alloys with only minor alloying additions of Sc and Zr, 0.5 wt.% max. Furthermore, by employing a simple direct ageing heat treatment, good tensile mechanical properties were observed with a yield strength of 308 MPa, an ultimate tensile strength of 390 MPa, and a total elongation of 11%.

Simultaneous Strength-Ductility Enhancement In As-Cast Ti6al4v Alloy By Trace Ce, K. M. Li, Y. J. Liu, X. C. Liu, X. Wu, S. F. Zhou, Laichang Zhang, W. Li, W. C. Zhang

Research outputs 2022 to 2026

Impurity elements always play a major role in hindering mechanical property improvement in Ti6Al4V, and specifically most of them e.g. O, P, Cl, and S dissolved in the matrix deteriorate the mechanical properties of Ti6Al4V. This work presents a strategy of enhancing the mechanical performance of as-cast Ti6Al4V alloy by adding a small amount of rare earth (i.e. 0.1 wt% Ce), where deleterious elements could be absorbed from the crystalline lattice during solidification process, forming uniformly distributed Ce-rich oxides or precipitates with ∼200 nm in size. The Ce-rich precipitates in turn refine the beta phase lamellae by introducing more nucleation …