scholarly journals Effect of Web Stiffeners on The Flexural Behavior of Composite GFRP- Concrete ‎Beam Under Impact Load

2021 ◽  
Vol 27 (3) ◽  
pp. 76-92
Author(s):  
Safaa Ibraheem Ali ◽  
Abbas A. Allawi
Keyword(s):  
Impact Load ◽  
Damping Ratio ◽  
Experimental Studies ◽  
Local Buckling ◽  
Structural Response ◽  
Point Load ◽  
Flexural Behavior ◽  
Elastic Behavior ◽  
Loading Path ◽  
Failure Behavior

In this paper, numerical and experimental studies on the elastic behavior of glass fiber reinforced ‎polymer (GFRP) with stiffeners in the GFRP section's web (to prevent local buckling) are presented. ‎The GFRP profiles‎ were connected to the concrete deck slab by shear connectors. Two full-scale simply supported ‎composite beams (with and without stiffeners) were tested under impact load (three-point load) to ‎assess its structural response. The results ‎proved that the maximum impact force, maximum ‎deflection, damping time, and ‎damping ratio of the composite beam were affected by the GFRP ‎stiffeners‎. The experimental results indicated that the damping ratio and deflection were diminished compared to hybrid beam without stiffeners by ‎‎16% and 22%, respectively, and increasing damping time‏ by 26%. Finite element models were used to study pre-failure behavior. ‎ The numerical modeling results showed good agreement with experimental data in terms of loading path and ‎final load. The damping ratio and midspan deflection values were greater than the experimental ‎values by 6% and 12%, respectively.

scholarly journals Numerical model for investigating seismic performance of Prestressed Hollow Concrete (PHC) piles with Fiber section element

2020 ◽  
Vol 156 ◽  
pp. 03007
Author(s):  
Angga Fajar Setiawan ◽  
Muhamad Fauzi Darmawan ◽  
Sito Ismanti ◽  
Sunarso Mukhlis ◽  
Adityawarman Guntara Muria
Keyword(s):  
Numerical Model ◽  
Seismic Performance ◽  
Damping Ratio ◽  
Plastic Hinge ◽  
Flexural Behavior ◽  
Elastic Behavior ◽  
Dissipated Energy ◽  
Seismic Load ◽  
Seismic Zone ◽  
Non Linear

In the medium to high seismic zone, prestressed hollow concrete (PHC) pile for structural foundation should be designed with elastic behavior due to low ductility and dissipated energy. However, some Indonesian practical engineer has chosen PHC pile for pile-supported slab viaduct (PSSV) with medium seismic moment-resisting frame concept in a high-risk earthquake zone. Therefore, some nonlinear numerical simulations of PSSV structure in medium to high seismic zone need to be conducted to investigate its seismic performance. In the initial stage, a numerical model for investigating the seismic performance of PHC pile under flexural test was conducted. By implementing an appropriate plastic hinge length of forced beam-column with hinge elements, the flexural behavior of PHC piles to be simulated under both monotonic and cyclic loading. The fiber section was adopted to accommodate non-linear behaviour of material in the PHC pile cross section. As the results, the skeleton curves, the sectional strain distributions, and the hysteresis curves have good agreement results compared with the experimental results. Furthermore, based on the equal damping ratio calculation of the hysteresis curve, the PHC pile only achieve low energy dissipation, though the ductility capacity around 3. Finally, this numerical model approach could be adopted in the non-linear simulation of PSSV structure under seismic load.

Structural Response and Remaining Life of Damaged Composites

2015 ◽  
Vol 813-814 ◽  
pp. 106-110
Author(s):  
Dalbir Singh ◽  
C. Ganesan ◽  
A. Rajaraman
Keyword(s):  
Hybrid Approach ◽  
Experimental Studies ◽  
Structural Response ◽  
Material Behavior ◽  
Experimental Results ◽  
Life Assessment ◽  
Nonlinear Material ◽  
Remaining Life ◽  
Design Effectiveness ◽  
Remaining Life Assessment

Composites are being used in variety of applications ranging from defense and aircraft structures, where usage is profuse, to vehicle structures and even for repair and rehabilitation. Most of these composites are made of different laminates glued together with matrix for binding and now-a-days fibers of different types are embedded in a composite matrix. The characterizations of material properties of composites are mostly experimental with analytical modeling used to simulate the system behavior. But many times, the composites develop damage or distress in the form of cracking while they are in service and this adds a different dimension as one has to evaluate the response with the damage so that its performance during its remaining life is satisfactory. This is the objective of the present study where a hybrid approach using experimental results on damaged specimens and then analytical finite element are used to evaluate response. This will considerably help in remaining life assessment-RLA- for composites with damage so that design effectiveness with damage could be assessed. This investigation has been carried out on a typical composite with carbon fiber reinforcements, manufactured by IPCL Baroda (India) with trade name INDCARF-30. Experimental studies were conducted on undamaged and damaged specimens to simulate normal continuous loading and discontinuous loading-and-unloading states in actual systems. Based on the experimental results, material characterization inputs are taken and analytical studies were carried out using ANSYS to assess the response under linear and nonlinear material behavior to find the stiffness decay. Using stiffness decay RLA was computed and curves are given to bring the influence of type of damage and load at which damage had occurred.

Vortex-Induced Vibrations of a Cylinder at Subcritical Reynolds Number

2011 ◽  
Author(s):  
Yoann Jus ◽  
Elisabeth Longatte ◽  
Jean-Camille Chassaing ◽  
Pierre Sagaut
Keyword(s):  
Reynolds Number ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Damping Ratio ◽  
Experimental Studies ◽  
Cross Flow ◽  
Physical Analysis ◽  
Arbitrary Lagrangian Eulerian ◽  
Vortex Induced Vibrations ◽  
Low Mass

The present work focusses on the numerical study of Vortex-Induced Vibrations (VIV) of an elastically mounted cylinder in a cross flow at moderate Reynolds numbers. Low mass-damping experimental studies show that the dynamic behavior of the cylinder exhibits a three-branch response model, depending on the range of the reduced velocity. However, few numerical simulations deal with accurate computations of the VIV amplitudes at the lock-in upper branch of the bifurcation diagram. In this work, the dynamic response of the cylinder is investigated by means of three-dimensional Large Eddy Simulation (LES). An Arbitrary Lagrangian Eulerian framework is employed to account for fluid solid interface boundary motion and grid deformation. Numerous numerical simulations are performed at a Reynolds number of 3900 for both no damping and low-mass damping ratio and various reduced velocities. A detailed physical analysis is conducted to show how the present methodology is able to capture the different VIV responses.

The York-Arup cable experiments: Implications for the fire design of cable-supported bridges

2021 ◽  
Author(s):  
Benjamin Nicoletta ◽  
John Gales ◽  
Panagiotis Kotsovinos
Keyword(s):  
Thermal Strain ◽  
Experimental Studies ◽  
Thermal Response ◽  
Structural Response ◽  
Fire Performance ◽  
Stay Cable ◽  
Stay Cables ◽  
Bridge Structures ◽  
Recent Trends ◽  
High Level

<p>Recent trends towards performance-based fire designs for complex and critical structures have posed questions about the fire resilience of bridge infrastructure. There are little-to-no code requirements for bridge fire resistance and practitioner guidance on the subject is limited. Research on the fire performance of cable-supported bridge structures is scarce and knowledge gaps persist that inhibit more informed fire protection designs in a variety of bridge types. There have been few numerical or experimental studies that investigate the fire performance of steel stay-cables for use in cable-supported bridges. The thermal response of these members is critical as cable systems are highly dependent on the response of individual members, such as in the case of an anchor cable for example. The study herein examines the thermal response of several varieties of unloaded steel- stay cable during exposure to a non-standard methanol pool fire and the implications for the structural response of a cable-supported bridge. Experimental thermal strain data from fire tests of various stay-cables is used to inform high-level insights for the global response of a cable-supported bridge. Namely, the effects of cable thermal expansion on the overall cable system is approximated.</p>

scholarly journals Experimental Studies on Punching Shear and Impact Resistance of Steel Fibre Reinforced Slag Based Geopolymer Concrete

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Srinivasan Karunanithi
Keyword(s):  
Energy Absorption ◽  
Steel Fibre ◽  
Impact Load ◽  
Impact Resistance ◽  
Experimental Studies ◽  
Absorption Capacity ◽  
Punching Shear ◽  
Geopolymer Concrete ◽  
Energy Absorption Capacity ◽  
Ultimate Failure

The study was focused on slag based geopolymer concrete with the addition of steel fibre. The slag based geopolymer concrete was under shear load and sudden impact load to determine its response. The punching shear represents the load dissipation of the material and the energy absorption capacity of the geopolymer concrete to impact load. The various percentage of steel fibre in the slag based geopolymer concrete was 0.5%, 1.0%, and 1.5%. Overall the dosage 0.5% of steel fibre reinforced slag based geopolymer shows better results with a punching shear of 224 kN and 1.0% of steel fibre incorporated geopolymer concrete had the better energy absorption capacity with 3774.40 N·m for first crack toughness and 4123.88 N·m for ultimate failure toughness.

scholarly journals Structural Assessment of the Hull Response of an FPSO Unit to Dropped Objects: A Case Study

2019 ◽  
Vol 26 (4) ◽  
pp. 39-46 ◽  
Author(s):  
Ozgur Ozguc
Keyword(s):  
Structural Damage ◽  
Local Buckling ◽  
Structural Response ◽  
Offshore Structures ◽  
Mechanical Equipment ◽  
Structural Members ◽  
Impact Area ◽  
Explicit Dynamic ◽  
The Impact

Abstract Offshore structures are exposed to the risk of damage caused by various types of extreme and accidental events, such as fire, explosion, collision, and dropped objects. These events cause structural damage in the impact area, including yielding of materials, local buckling, and in some cases local failure and penetration. The structural response of an FPSO hull subjected to events involving dropped objects is investigated in this study, and non-linear finite element analyses are carried out using an explicit dynamic code written LS-DYNA software. The scenarios involving dropped objects are based on the impact from the fall of a container and rigid mechanical equipment. Impact analyses of the dropped objects demonstrated that even though some structural members were permanently deformed by drop loads, no failure took place in accordance with the plastic strain criteria, as per NORSOK standards. The findings and insights derived from the present study may be informative in the safe design of floating offshore structures.

Seismic Performance of T-Shaped CFT Column to Steel Frame Beam Connection – Experimental Study

2014 ◽  
Vol 919-921 ◽  
pp. 951-959 ◽  
Author(s):  
Yan Tao Li ◽  
Cheng Xiang Xu ◽  
Guo Feng Du
Keyword(s):  
Failure Mechanism ◽  
Damping Ratio ◽  
Local Buckling ◽  
Steel Tube ◽  
Steel Frame ◽  
Hysteretic Behavior ◽  
Stiffness Ratio ◽  
Joint Models ◽  
Panel Zone ◽  
Axial Forces

The focus of this research program is T-shaped CFT central column to steel frame beam connection. 3 joints with strong columns-weak beams and 1 joint with strong beams-weak columns 1:2 scale specimens were tested under constant axial loads and cyclic horizontal loads. Overall impact of axial force ratio and beam to column linear stiffness ratio on joint failure mechanism, hysteretic behavior, deformation ductility, and energy dissipation capability was investigated. Results showed that the failure mechanism for specimens with strong columns-weak beams was local buckling of the steel beam flanges and formation of the plastic hinges. There was minimum damage on the concrete column and joint panel zone. For a specimen with strong beams-weak columns, there was local buckling fracture on steel tube above and below the joint panel zone. Crushing of the core concrete was also observed with formation of the column hinges. It was found that both axial forces and beam to column linear stiffness ratio had impacts on joint capacity and ductility behavior of the specimens. Experiment results showed that the joint models had deformation ductility factor between 3.39 and 3.91 and viscous damping ratio between 0.46 and 0.51.

scholarly journals Harnessing the interface mechanics of hard films and soft substrates for 3D assembly by controlled buckling

2019 ◽  
Vol 116 (31) ◽  
pp. 15368-15377 ◽  
Author(s):  
Yuan Liu ◽  
Xueju Wang ◽  
Yameng Xu ◽  
Zhaoguo Xue ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Functional Materials ◽  
Loading Path ◽  
Weak Interface ◽  
Nonlinear Buckling ◽  
Micromechanical Resonators ◽  
Diverse Range ◽  
3D Assembly ◽  
Engineering Parameters

Techniques for forming sophisticated, 3D mesostructures in advanced, functional materials are of rapidly growing interest, owing to their potential uses across a broad range of fundamental and applied areas of application. Recently developed approaches to 3D assembly that rely on controlled buckling mechanics serve as versatile routes to 3D mesostructures in a diverse range of high-quality materials and length scales of relevance for 3D microsystems with unusual function and/or enhanced performance. Nonlinear buckling and delamination behaviors in materials that combine both weak and strong interfaces are foundational to the assembly process, but they can be difficult to control, especially for complex geometries. This paper presents theoretical and experimental studies of the fundamental aspects of adhesion and delamination in this context. By quantifying the effects of various essential parameters on these processes, we establish general design diagrams for different material systems, taking into account 4 dominant delamination states (wrinkling, partial delamination of the weak interface, full delamination of the weak interface, and partial delamination of the strong interface). These diagrams provide guidelines for the selection of engineering parameters that avoid interface-related failure, as demonstrated by a series of examples in 3D helical mesostructures and mesostructures that are reconfigurable based on the control of loading-path trajectories. Three-dimensional micromechanical resonators with frequencies that can be selected between 2 distinct values serve as demonstrative examples.

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