Sheng-Wei Chi, Department of Civil and Materials Engineering, UIC Primary Grant Support: UIC
Problem Statement and Motivation
Progressive penetration processes and predicted damage and contact surfaces
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Increasing demands are placed on materials and structures to withstand complex phenomena due to extreme loads such as impact and penetration.
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Key issues needed to be addressed in penetration simulation include high strain rate, extreme large deformation, material fracture, and fragment impact.
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The study aims to develop a multiscale meshfree approach for modeling fragment penetration into concrete.
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The ultimate goal is to understand better the phenomena in the penetration process and to predict the structure response under extreme loads.
Comparison of experimental and numerical damage patterns
Key Achievements and Future Goals
Technical Approach • • • •
Semi-Lagrangian Reproducing Kernel Particle formulation in which the point discretization follows the material while the radius of interaction of a point is fixed in Euler coordinates. Levelset enhanced kernel contact algorithm Image-based meso-scale concrete fracture simulation Microstructure informed damage model Meshfree discretization
p
0
Schematic of image-based meso-scale concrete fracture simulation
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Develop a levelset enhanced kernel contact algorithm that does not require a predefined contact surface.
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Develop an image-based computational approach to effectively construct a computer model based on cross sectional images.
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Develop a concrete constitutive model based on the damage evolution in the meso-scale via the energy bridge theory.
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The future Goal of this study is to take into consideration multi-physics phenomena in penetration simulations, including: • • •
Thermo effects Rate effects on concrete and projectiles Shock wave
Maen Farhat, Momenur Rahman, Mustapha Ibrahim and Mohsen Issa, Univeristy of Illinois at Chicago Primary Grant Support: Utility Concrete Products (UCP)
Problem Statement and Motivation •
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Key Achievements and Future Goals
Technical Approach •
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Perform experimental study on a 20 ft. high, 166 in. wide full scale prototype (TPCCRW) to asses the strength and service behavior of the wall: Identify the optimum methods and stages of fabrication and prepare an advanced instrumentation and monitoring system that will allow to examine the behavior of the wall at different locations. The TPCCRW was tested experimentally by soil backfilling to simulate real life applications followed by applying load scenarios (4 different tests) reaching 200 kips by using hydraulic actuators. Conduct a finite element analysis using ANSYS package. The nonlinear analysis is carried out imitating the exact construction sequence of a retaining-wall backfills and surcharge loads.
Totally Precast Concrete Counterfort Retaining Wall (TPCCRW) system is an innovative solution to the growing need to develop sustainable retaining wall systems. It provides means for fast track construction that would significantly cut off the time of the construction and erection processes. It is designed to satisfy the code requirements for strength, serviceability, durability and constructability within the least possible cost and the maximum possible safety margins. The fully precast retaining wall system consisted of the face panel and 3 counterforts fabricated as a single entity and assembled with the precast base slab. From each counterfort, 5 headed anchors were extended and grouted in the base slab.
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The anchors, being the most critical component, succeeded to maintain serviceability, and ultimate strength requirements per AASHTO LRFD. The wall deflection in the middle (H/2) did not exceed 0.2 in. and did not exceed the allowable limits. An accurate finite element model capable of predicting the performance of TPCCRW was calibrated with the acquired experimental data using ANSYS software. A comprehensive design for the TPCCRW meeting the requirements of AASHTO LRFD was performed. Future parametric study using the validated finite element model. Additional experimental Investigation of the performance of the headed anchors when subjected to pullout load.
Ibrahim Lotfy, Maen Farhat and Mohsen Issa, Univeristy of Illinois at Chicago Primary Grant Support: NURail Center (U.S. DOT-RITA)
Problem Statement and Motivation •
• 13,000
Ultimate Pullout Load, lbs
12,000 11,000 10,000 9,000 8,000 7,000
6,000 Setup A
Setup B Setup C Setup Type
Setup D
0.5
1 2 Stroke (in./min)
73oF 100oF 125oF Temperature (oF)
Key Achievements and Future Goals
Technical Approach Striving to assess the feasibility of implementing HDPE crossties in rail applications, this study examined the behavior of the fastening system. I. Perform experimental testing as per AREMA specifications: • Investigate the behavior of the fastening system components of HDPE crossties under different loading, temperatures and setup conditions (spike pullout, spike lateral resistance and fastener uplift).
II. Conduct a finite element analysis using ANSYS: • Develop a modelling technique capable of properly simulating the interactions between each component in the system along with its effect on the HDPE crosstie.
High Density Polyethylene (HDPE) is a green, recyclable, and environmental friendly material. It has structural and economical advantages which grant it a competitive edge among other alternatives in the rail market such as wooden and concrete crossties The implementation of the new recycled Plastic railroad crossties would improve the railroad industry public image as a green, sustainable industry. The recycled products are manufactured with plastic waste that otherwise would be landfilled which reduces the waste products and additionally eliminates any pollution or deforestation. Moreover, Recycled, HDPE crossties are light, workable, easy to transport and handle, can overcome the main issues facing other materials and can replace wooden crossties on a one-to-one basis without the need for special installation or heavy equipment.
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The fastening system components satisfied and surpassed the AREMA requirements for polymer composite crossties in terms of fastener uplift and spike pullout and lateral restraint. An accurate finite element model capable of predicting the performance of each component was constructed and calibrated with the acquired experimental data using ANSYS software. Experimental Investigation of the performance of the crosstie and fastening system when subjected to cyclic loading and wear/abrasion. Further optimization and calibration of the material model. Implementation of the HDPE crossties in elevated structure-bridge applications as well as assessment the track bridge interactions.
Secondary Supporters: Tangent Technologies and the Chicago Transit Authority
Ibrahim Lotfy, Maen Farhat and Mohsen Issa, Univeristy of Illinois at Chicago Primary Grant Support: NURail Center (U.S. DOT-RITA)
Problem Statement and Motivation •
• 4,000 3,500 3,000
STRESS, psi
2,500 2,000 1,500
10 F 40 F 73 F 100 F 125 F
1,000
500 0 0.00
0.01
0.02 0.03 0.04 STRAIN, in./in.
0.05
0.06
Key Achievements and Future Goals
Technical Approach Striving to assess the feasibility of implementing HDPE crossties in rail applications, this study examines its flexural behavior. I. Perform experimental testing as per AREMA specifications: • Investigate the flexural behavior, cracking and failure modes of HDPE Crossties under different conditions; center and rail seat bending. • Assess the effect of temperature changes on the flexural and mechanical properties of the HDPE crossties. II. Conduct a finite element analysis using ANSYS: • Construct a calibrated non-linear material model for use in subsequent analyses. • Develop a suitable modelling technique which portrays the actual behavior of the crosstie.
High Density Polyethylene (HDPE) is a green, recyclable, and environmental friendly material. It has structural and economical advantages which grant it a competitive edge among other alternatives in the rail market such as wooden and concrete crossties The implementation of the new recycled Plastic railroad crossties would improve the railroad industry public image as a green, sustainable industry. The recycled products are manufactured with plastic waste that otherwise would be landfilled which reduces the waste products and additionally eliminates any pollution or deforestation. Moreover, Recycled, HDPE crossties are light, workable, easy to transport and handle, can overcome the main issues facing other materials and can replace wooden crossties on a one-to-one basis without the need for special installation or heavy equipment.
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The HDPE crossties satisfied and surpassed the AREMA requirements for polymer composite crossties in terms of flexural strength and stiffness (MOE and MOR). An accurate material model capable of predicting the flexural performance of HDPE crossties was constructed and calibrated with the acquired experimental data using ANSYS finite element package. Experimental Investigation of the performance of the crosstie and fastening system when subjected to cyclic loading and wear/abrasion. Further optimization and calibration of the material model. Implementation of the HDPE crossties in elevated structure-bridge applications as well as assessment the track bridge interactions.
Secondary Supporters: Tangent Technologies and the Chicago Transit Authority
Aiman Shibli and Mohsen Issa, University of Illinois at Chicago
Problem Statement and Motivation 9 8 7 6 5 4 3 2 1 0
Shear Test:
#1 #2 #3 #4 #5
0
5
10 Tensile strain
15
Spc-1 [14 days curing] Spc-2 [14 days curing]
0.5
1
1.5
2
Strain
Ball Drop :
Accelerometer
PC Supporting pin
Supporting pin
Supporting pin
Strain Gauges
Strain Gauges
0.01
Sim - Gauge - Top Sim - Gauge - Bot Test - Gauge - Bot Test - Gauge - Top
Big Plate: 70mmX20mmX1mm Small Plate: 20mmX20mmX1mm Adhesive: 70mmX20mmX0.2mm Top Span: 35mm Bottom Span: 60mm
Supporting pin
Test - Gauge - Top Sim - Gauge Bot
0.006
Sim - Gauge Top
0.004 50
•
Test - Gauge - Bot
0.008
100
150
200
250
Strain
Strain
0.01 0.008 0.006 0.004 0.002 0 -0.002 0 -0.004 -0.006 -0.008 -0.01
•
Spc-3 [7 days curing]
0
20
Loading pins
Four Point Bending:
9 8 7 6 5 4 3 2 1 0
Stress [Mpa]
Tensile stress [MPa]
Tensile Test:
•
0.002 0 -0.002
Force [N]
0
0.002
-0.004
0.004
0.006
Time (sec)
Key Achievements and Future Goals
Technical Approach • • •
Fiber-reinforced polymer (FRP) composites are increasingly used in structural applications due to their advantageous material properties. However, structural FRP components are difficult to connect using the traditional joining methods such bolting and riveting due to the brittle fibrous and anisotropic nature of the materials. Many structural industries have seen the use of adhesive for joining load-bearing components as an excellent candidate for replacing the traditional joining due to their unique characteristics such: high strength, light weight, dimensional stability, high joint efficiency and ease of use. In order to utilize adhesives bonding in civil infrastructure applications, it is crucial to understand their behavior and strength and to be able to predict it for a given geometries and loads.
Characterize adhesive’s mechanical property under tensile and shear loadings, at low and high rates (static and dynamic). Build representative material model that can mimic their behavior and can be used in numerical models for computational studies. Validate material model experimentally and computationally at coupon level and sub-system level at quasi-static and dynamic loadings.
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Quasi-static and dynamic experiments were completed on structural adhesive at different loading modes: tension and shear. Material model has been created and validated at coupon level and subsystem level, under quasi-static and dynamic loadings. Comparison between experimental results and numerical results obtained from 3D finite element analysis showed very good correlation at different loading modes and rates. Future work, this study need to be implemented and investigated in real case application
Mustapha Ibrahim, Mohsen Issa, PhD, and Mustafa Al-Obaidi, Univeristy of Illinois at Chicago Primary Grant Support: Illinois Department of Transportation (IDOT)
Problem Statement and Motivation • •
Cement production account for more than 5% of CO2 emission worldwide. On average, each ton of cement produced from a cement plant accounts for 0.92 tons of CO2 emissions. Reducing this carbon emission requires a breakthrough technology that might take decades to be adopted by the cement industry. One of the low-cost successful methods that aided in developing a more sustainable production program was in adding pulverized limestone and other inorganic processing to cement, reducing the amount of clinker in its production. IDOT is making several changes to concrete mix designs by applying revisions to cement specification. These proposed revisions will enable the use of more limestone and inorganic processing additions (IPA) (sustainable materials) for concrete pavements, overlays, and bridge decks. A study was conducted to test the performance of concrete mixes batched with cement comprising of higher quantities of limestone and IPA.
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Key Achievements and Future Goals
Technical Approach • •
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The goal is to develop economical and practical concrete mixes that would provide sustainable and durable concrete pavements. Twenty-four concrete mixes with different cementitious combinations and aggregates were developed for this study. Three sources of cement were used. The mix combination of each cement source is shown below: • The program included testing the fresh and hardened strength and durability properties of concrete. • The fresh properties included measuring the slump, air content, unit weight, and setting time. The strength properties included testing the compressive and flexural strength of concrete. The durability properties included testing the Freeze and thaw resistance and rapid dynamic modulus of concrete, microscopic hardened entrained air, rapid chloride penetration resistance, salt ponding and chloride ion penetration, and water permeability.
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The use of limestone and IPA in cement with quantities above the specified limits proved to have similar performance to conventional cement when mixed in concrete. The use of different cementitious materials (Fly Ash or Slag) improved the durability of concrete The success of this project prompted the IDOT to adopt the use of the new modified cement in replacement to the conventional cement. The amount of cement used in concrete batching was 375 lbs/yd3 which is the minimum cement content required by IDOT. As a result of this study, the amount of cement was increased from 375 lbs/yd3 to 400 lbs/yd3. Future development of concrete service life predictions and models to study the chloride ingress/ diffusion in concrete and its resistance to freeze and thaw.
Hossain Saboonchi, PhD Student and Didem Ozevin, Assistant Professor Department of Civil and Materials Engineering Primary Grant Support: UIC, Faculty Research Award Out of plane AE sensor (fn=50 kHz)
Problem Statement and Motivation
Out of plane AE sensor (fn=200 kHz)
In plane Inertia Switch (fn=150 Hz) Out of plane Inertia Switch (fn=100 Hz) Strain Sensors (120 Ω & 350 Ω)
Capacitance change
In plane AE sensor–gap change (fn=150 kHz)
SEM image of MEMS strain sensor
In plane AE sensor–area change (fn=100 kHz)
dC d dA dg Co A g
• Acoustic Emission is a highly sensitive Structural Health Monitoring method to monitor damage in aging structures. However, the sensitivity to environmental noise requires significant post-processing to differentiate the relevant data. • Single SHM method may not be sufficient for reliable damage detection and diagnostics. Multiple information collection simultaneously reduces the uncertainty.
SEM image of In plane AE sensor–gap change (fn=150 kHz)
Technical Approach • Multiple sensing elements are designed on the same device, including acoustic emission sensor to measure motions in out-of-plane and in-plane, strain and vibration to be used as inertia switch to activate AE collection. • The response of in-plane sensor to the out-of-plane motion is eliminated through novel differential mode approach. • The AE sensor is connected to on-chip inertia switch in order to collect AE data when the structure is highly stressed. The hypothesis is that the crack grows when the structure is loaded above a certain level.
• MEMS allow manufacturing multiple sensing mechanisms on the same device.
Key Achievements and Future Goals • The MEMS sensors are designed, modeled using COMSOL Multiphysics software and manufactured using MetalMUMPS process.
MEMS AE sensor
• The electrical and mechanical characterizations are completed. • The device will be tested in laboratory for detecting crack initiation and growth.
MEMS strain sensor
Didem Ozevin, Assistant Professor, Zahra Heidary PhD Student, Nadia Simek Undergraduate Student Department of Civil and Materials Engineering Primary Grant Support: NSF
Problem Statement and Motivation
single point leak localization
• The buried and on-ground pipelines develop damage due to temporal variables such as corrosion and creep or instantaneous threats such as earthquake and impact.
New Approach with Particular Geometry Sensor Design
• The detection of leaking at oil, water or natural gas pipelines before reaching structural instability can increase the public safety and prevent environmental pollution. • Passive nature of Acoustic Emission implemented for real time leak detection.
method
can
be
• The challenge is that the sensor sensitivity and wave attenuation prevent a reasonable sensor spacing for pipeline networks.
Technical Approach • The numerical models are linked with experimental studies to understand the reliable leak detection range and sensor spacing. The waveform properties of leaks due to different operational conditions can be identified experimentally. • Shear type Acoustic Emission sensor increases the sensor spacing range due to less attenuative characteristics of longitudinal waves. • Highly efficient numerical formulation is developed to study wave propagation in pipes due to non-axisymmetric loading. • Wave characteristics due to different leak rates for different frequencies are investigated.
Key Achievements and Future Goals • The AE characteristics due to varying pipe pressure, leak size and earth pressure are identified. Numerical attenuation curves are driven. • The AE sensor is designed with a particular geometry, modeled numerically and manufactured. • The developed transducer and the numerical model will be tested in a field condition.
Comparison of 2D efficient model with conventional 3D models
Didem Ozevin, Assistant Professor and Zeynab Abbasi PhD Student Department of Civil and Materials Engineering Primary Grant Support: TRB IDEA and NSF
Problem Statement and Motivation Complex loading case
Wave change with stress
Laboratory calibration for biaxial loading for existing equation as
Technical Approach • The research objective of this proposal is to understand the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded critical structural components in order to measure the stress state at a given cross section. • The goal is to quantify the normal stresses and shear stress at a given cross section, which will be achieved through testing a set of frequencies to create Rayleigh waves with varying depth of penetration. • The equation in the literature will be modified to introduce the effect of shear stress on nonlinear ultrasonic measurement as
Dv = K1s 1 + K 2s 2 + K3s 12 vo
• Understanding the risk for a built structural element requires knowledge of the cumulative stress state in order to estimate the remaining strength such as residual stress and excessive loading condition. • A reliable damage prognostic approach should have a welldefined damage accumulation function. • The quantification of the cumulative stress state for a built element is needed for preventing unexpected failures at highrisk structural elements. • Currently, there is no nondestructive testing method to find stress tensor including normal and shear stresses.
Key Achievements and Future Goals • Multi-scale bridge model is built to estimate stresses at a 3/8 inch thick gusset plate. • An ultrasonic measurement device to quantify the stress at three directions is built.
• The measurements from laboratory scale plate will be conducted and theoretical equations will be modified to include the shear stress.
Eduard Karpov, CME Primary Grant Support: National Science Foundation
Problem Statement and Motivation •
• •
• • Typical deterministic multiscale modeling approach; Broughton, PRB 60(4)
Creep cavity in 304 austenitic steel, and its self-healing mechanism by BN surface precipitation; Shinya, IJMSS 17
Key Achievements and Future Goals
Technical Approach •
Continuum scale finite element model reflects the concurrent atomistic configuration via frequently updated material properties, while the kinetic Monte-Carlo model utilizes deformation parameters for an update of interatomic geometry and microscopic diffusion rates
Modern functional materials for engineering and medical applications are designed to perform a self-controlled smart action, similar to a living creature able to sense and process the environment and take necessary actions Self-healing materials is one important class of evolutionary smart materials The smart action is related to a progressive change of constitutive material properties at a macroscopic interval of time, governed by atomic scale processes Interplay between the mechanical performance and the internal structure dynamics can be two-way Deterministic multiscale modeling approaches with an atomistic resolution based on molecular dynamics are inadequate in application to the evolutionary materials, due to physical time limitations
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An efficient mechanokinetic coupling methodology has been developed and applied to the to biomimetic crack self-healing by surface precipitation under external mechanical loading Physical time is derived statistically from temporal characteristics of small scale processes to enable modeling over macroscopic intervals of physical time with an atomistic resolution Qualitative trends of the self-healing problem are compliant with experimental observations, while the modeling takes the analysis far beyond available empirical data and current experimental capabilities The proposed methodology is applicable to a wide class of evolutionary processes including strain dependant diffusion, nanostructure synthesis, material chemical transformations, surface chemical waves and adsorbate dynamics
Eduard Karpov, CME Primary Grant Support: National Science Foundation
Problem Statement and Motivation • •
• • Hot electron mechanism of electrolyte-free chemical to electrical energy conversion; Karpov et al., APL 94, 214101
Key Achievements and Future Goals
Technical Approach • •
Electric charge separation and the resultant electromotive force can be achieved in electrically continuous metal-semiconductor catalytic structures with nanometer thickness metallization (diagram above) Metal nanofilm thickness must be smaller than the hot electron mean free path that is 10-50 nm for most catalytic metals Laboratory system setup for hot electron current detection: (1) vacuum/gas handling components (2) mass spectrometer (3) signal conditioning unit (4) multichannel temperature controller (5) analytical chamber (6) main flange for sample mounting (7) high precision V/A source
Traditional fuel cell technologies based on ground-state electrochemistry suffer from slow-rate ionic diffusion, spurious electronic conduction in electrolytes and electrolyte degradation At the same time, synergistic catalytic effects observed in composite catalysts, in particular, in photocatalysts with a nanodispersed metal phase is surprising. Evidence exists that it owes to an exchange of inequilibrium charge carriers (hot electrons) at the metal/nonmetal support interface Reaction induced hot electron flow in a class of electrically continuous metal-semiconductor catalytic nanostructures provide a hope for “electrolyte-free chemical to electrical energy conversion” Hot electron currents detected in metal-semiconductor nanostructures also provide a valuable in-situ analytical tool to study basic physical mechanisms of heterogeneous catalysis
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Studies of Pd/SiC, Pd/GaP and Pt/GaP prototypes revealed the hot electron component to comprise 60-85% of the total current induced by the H2+1/2O2 = H2O surface reaction, and the remaining fraction belongs to the usual thermal currents Reliable techniques to separate the hot electron and thermal currents have been developed Electron yield of a potential electrical generator was 0.20 for the SiCand 0.11 for GaP-based prototypes, implying a big promise for this electrolyte-free chemical-electrical energy conversion approach The hot electron current was also demonstrated for identification of distinct modes of the surface reaction Higher efficiency material systems operating at room temperature are currently underway
J.E. Indacochea, M.L. Wang, Department of Civil and Materials Engineering, UIC H.H. Wang, Materials Science Division, Argonne National Laboratory Primary Grant Support: National Science Foundation AAO nanowell
Problem Statement and Motivation Pd nanoparticle
0.735
Al substrate
H off
1% H
0.734
•
Hydrogen has been envisioned as a futuristic energy system. Gas detectors will be key components to ensure safety and reliability in hydrogen infrastructure.
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Limitations of current hydrogen sensing devices include long response time, low sensitivity, and poor performance at room temperature.
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Very large active surface and nanoscale dimensions make nanostructures a promising alternative to overcome current limitations in hydrogen detectors.
Resistance (kOhm)
0.733 0.5% H
0.732 0.3% H 0.2% H
0.731
0.1% H
0.73
0.05% H
H on
0.729 0.728 0.727 0
20
40
60
80
100
120
140
160
Time (s)
Change in resistance in presence of hydrogen at different concentrations
Key Achievements and Future Goals
Technical Approach •
Anodic aluminum oxide (AAO) nanowell array has been selected as substrate because it provides a robust, insulating, and ordered structure for catalyst deposition.
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Pd nanoparticles have been selected as catalyst due to their high sensitivity and selectivity to react with hydrogen.
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The nanostructure is being characterized and tested for hydrogen detection. Dimensions and configuration are being systematically studied to achieve optimal performance.
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The electrical resistance of the nanostructure increases with hydrogen concentration due to the formation of a non conductive Pd hydride phase.
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Response time is greatly faster compared to that for other nanostructured and micro sensing devices.
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Very low hydrogen concentrations can be detected at room temperature without compromising sensitivity.
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The main goal is to achieve optimal performance and integrate the nanostructure into modern sensors.
Michael McNallan, Civil and Materials Engineering, UIC; Ali Erdemir, Argonne National Laboratory Primary Grant Support: U.S. Department of Energy 752
400
•
Mechanical Seals and bearings fail due to frictional heating and wear
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Materials used are hard ceramics, such as SiC or WC
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Friction can be reduced by coating with carbon as graphite or diamond
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Graphitic coatings are not wear resistant
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Diamond coatings are wear resistant, but fail by spallation or delamination from the underlying ceramic
572
max. safe temperature
M A X . S A F E T EM P . F O R HNBR
SiC-SiC
200
392
SiC-CDC 100
°F
S T AT O R O .D . T E M P . °C
300
Problem Statement and Motivation
212
0 0
60
120
180
240
300
360
420
480
540
600
660
720
780
840
900
T IM E (S )
Pump seal face temperature during dry running at 4000 rpm with and without CDC coating
Key Achievements and Future Goals
Technical Approach •
Produce a low friction carbon layer by chemical conversion of the surface of the carbide
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SiC(s) + 2Cl2(g) SiCl4(g) + C(s)
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At temperatures < 1000oC, carbon cannot relax into equilibrium graphitic state and remains as Carbide Derived Carbon (CDC)
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CDC coating contains nano-porous amorphous C, fullerenes, and nanocrystalline diamond
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CDC is low friction, wear resistant, and resistant to spallation and delamination
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CDC has been produced in the laboratory
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It’s structure and conversion kinetics have been characterized
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Tribological performance was verified in laboratory and industrial scale pump tests with water
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CDC was patented and selected for an R&D 100 Award in 2003
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CDC was Licensed to Carbide Derivative Technologies, Inc.in 2006
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Scale up to industrial production rates, characterization of process reliability and testing in specific industrial environments is the next goal.