scholarly journals Design of a Prototype for the In Situ Forming of a Liquid-Infused Preform Process

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Jaime Juan ◽  
M. Núria Salán ◽  
Arlindo Silva ◽  
José A. Tornero
Keyword(s):  
Experimental Validation ◽  
Mechanical Design ◽  
Fiber Reinforced Polymer ◽  
Infrared Heating ◽  
Full Potential ◽  
In Situ Forming ◽  
Reinforced Polymer ◽  
Diaphragm System ◽  
Functional Prototype

Abstract The world is changing and demanding stronger, lighter, and more versatile materials. Taking advantage of the full potential of these materials also requires versatile manufacturing processes. The in situ forming of a liquid-infused preform (ISFLIP) is a new manufacturing process for fiber-reinforced polymer (FRP) parts with shell shapes. ISFLIP is a hybrid process between vacuum infusion (VI) and diaphragm forming. This paper focuses on the mechanical design and experimental validation of a functional prototype of ISFLIP. The novelty of the design lies especially in a double-diaphragm system that is fundamental to carrying out the forming just after the infusion stage. The double-diaphragm system and other two major subsystems, a vacuum table and an infrared heating grid, were devised to benefit from the operational advantages of ISFLIP. The whole prototype, once constructed, was tested by forming some demonstration components. The result of one of these components, a “C” cross-section FRP profile with two sharp joggles, is finally obtained, proving the feasibility of the prototype.

Seismic Strengthening of Reinforced-Concrete Multicolumn Bridge Piers

2007 ◽  
Vol 23 (3) ◽  
pp. 635-664 ◽  
Author(s):  
Chris P. Pantelides ◽  
Jeffrey B. Duffin ◽  
Lawrence D. Reaveley
Keyword(s):  
Reinforced Concrete ◽  
Bridge Pier ◽  
Fiber Reinforced Polymer ◽  
Bridge Piers ◽  
Seismic Rehabilitation ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Pile Caps ◽  
Rehabilitation Measures

The analysis, seismic rehabilitation measures, and in-situ performance of a reinforced-concrete (RC) bridge pier subjected to quasi-static loads are presented. The bridge was built in 1963 and was designed for gravity and wind but not seismic loads. The reinforcement details are compared with AASHTO requirements for seismic zones 3 and 4. The bridge pier was rehabilitated with steel dowels connecting the piles to the pile caps and RC grade beam connecting the three pile caps; carbon Fiber-Reinforced-Polymer (FRP) composite jackets were used to rehabilitate the columns, cap beam, and T-joints. An analytical model is presented that includes the effects of soil-pile-structure interaction and the seismic rehabilitation measures. Critical events in the experimental performance of the bridge pier are identified. Comparisons are made between the pier's performance and that of other piers tested in situ at the same site that were rehabilitated with incremental measures.

scholarly journals Conductivity-Based Damage Detection in Carbon Fiber Composites

2012 ◽  
Author(s):  
Bryan R. Loyola ◽  
Luciana Arronche ◽  
Valeria La Saponara ◽  
Kenneth J. Loh
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Damage Detection ◽  
Composite Laminates ◽  
Electrical Impedance ◽  
Fiber Reinforced Polymer ◽  
Impedance Tomography ◽  
Frp Composites ◽  
Reinforced Polymer

Fiber-reinforced polymer (FRP) composites have become a primary structural material in many new structures, particularly in the aerospace, wind turbine, automobile, and marine industries, due to their higher strength-to-weight ratios, corrosion resistance, and ease of manufacturing. However, these composite materials have complex damages modes that are different from typical monolithic metallic alloys, such as delamination, fiber breakage, matrix cracking, and fiber-matrix debonding. These avenues of damage tend to manifest internally to the composite structure, making them nearly invisible to visual inspection. Several damage detection approaches have been introduced for the purpose of in situ non-destructive evaluation (NDE) of composites; however, many of these approaches require complex analysis methods, data interpolation for achieving spatial sensing, and/or embedding invasive sensors into the composites themselves. To allow for widespread implementation of a next-generation NDE approach for composites, an easily discernible, highly visual, and fast approach that does not adversely affect the structural performance of the composite laminate is needed. This study introduces the use of a spatially distributed electrical conductivity distribution mapping method called electrical impedance tomography (EIT). EIT reconstructs a material’s 2D or 3D electrical conductivity within a series of boundary electrodes. A 100 mA current is injected between two opposing electrodes while the adjacent differential voltages are measured at the remaining electrodes; this process is repeated for all opposing electrode pairs. Using a linear reconstruction algorithm, changes in electrical conductivity are spatially resolved and plotted for easy detection, localization, and evaluation of damage. This approach is validated by applying EIT to a set of carbon fiber-reinforced polymer composite laminates. First, damage has been simulated in composite parts by selectively removing portions of the structure and then verifying that EIT has captured this occurrence. After validation of the EIT method, pristine composite laminates have been subjected to low velocity impact damage. Before and after impact EIT readings have been taken. The differential conductivity reconstruction is presented. This work demonstrates the value of adopting electrical impedance tomography for in situ NDE of FRP composites.

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