More Like this

1. Wavefield Analysis Enabled Multi-Directional Mechanical Properties Characterization for 3D Printed Composites

   https://doi.org/10.1115/IMECE2024-147340  

   Cai, Bowen; Watts, Hunter; Sun, Chuangchuang; Huberty, Wayne; Tian, Zhenhua (November 2024, American Society of Mechanical Engineers)

   Abstract Thermoset composites, utilized in additive manufacturing, are distinguished by their excellent thermal and mechanical properties, enabling them to maintain structural integrity even under high-temperature conditions. An accurate method for characterizing the mechanical properties is necessary to ensure the performance parameters, reliability, and safety of materials during and post-manufacturing. However, characterizing 3D-printed thermoset composites is challenging due to the anisotropy introduced by the additive manufacturing process and factors such as delamination and porosity. This also leads to difficulties in accurately characterizing composites with traditional testing methods. To address this, this paper introduces a novel method that combines a non-destructive Piezoelectric transducer-laser Doppler Vibrometer (PZT-LDV) guided wave sensing system with an optimization algorithm-enhanced wavenumber analysis technique. A series of experiments were conducted to validate the concept of measuring the mechanical properties of a 3D-printed thermoset material panel. Our method successfully determined two material properties — shear wave speed and Poisson’s ratio in multiple directions on the test panel. This study aims to establish a precise and rapid non-destructive testing method that can effectively characterize various composite materials and monitor their performance throughout the additive manufacturing process. 

   more » « less
2. Durability of Externally Bonded Fiber-Reinforced Polymer Composites in Concrete Structures: A Critical Review

   https://doi.org/https://doi.org/10.3390/polym13050765  

   Tatar, Jovan; Milev, Sandra (February 2021, Polymers)

   Frigione, Mariaenrica (Ed.)

   Externally bonded fiber-reinforced polymer composites have been in use in civil infrastructure for decades, but their long-term performance is still difficult to predict due to many knowledge gaps in the understanding of degradation mechanisms. This paper summarizes critical durability issues associated with the application of fiber-reinforced polymer (FRP) composites for rehabilitation of concrete structures. A variety of factors that affect the longevity of FRP composites are discussed: installation, quality control, material selection, and environmental conditions. Critical review of design approaches currently used in various international design guidelines is presented to identify potential opportunities for refinement of design guidance with respect to durability. Interdisciplinary approaches that combine materials science and structural engineering are recognized as having potential to develop composites with improved durability. 

   more » « less
3. Optimizing Truss Structures Using Composite Materials under Natural Frequency Constraints with a New Hybrid Algorithm Based on Cuckoo Search and Stochastic Paint Optimizer (CSSPO)

   https://doi.org/10.3390/buildings13061551  

   Khodadadi, Nima; Harati, Ehsan; De Caso, Francisco; Nanni, Antonio (June 2023, Buildings)

   This article highlights the absence of published paradigms hybridized by The Cuckoo Search (CS) and Stochastic Paint Optimizer (SPO) for optimizing truss structures using composite materials under natural frequency constraints. The article proposes a novel optimization algorithm called CSSPO for optimizing truss structures made of composite materials, known as fiber-reinforced polymer (FRP) composites, to address this gap. Optimization problems of truss structures under frequency constraints are recognized as challenging due to their non-linear and non-convex search spaces that contain numerous local optima. The proposed methodology produces high-quality optimal solutions with less computational effort than the original methods. The aim of this work is to compare the performance of carbon FRP (CFRP), glass FRP (GFRP), and steel using a novel hybrid algorithm to provide valuable insights and inform decision-making processes in material selection and design. Four benchmark structure trusses with natural frequency constraints were utilized to demonstrate the efficiency and robustness of the CSSPO. The numerical analysis findings indicate that the CSSPO outperforms the classical SPO and exhibits comparable or superior performance when compared to the SPO. The study highlights that implementing CFRP and GFRP composites in truss construction leads to a notable reduction in weight compared to using steel. 

   more » « less
4. Structural analysis of FRP parts from waste wind turbine blades for building reuse applications

   Lawrence C. Bank, Franco R. (September 2019, Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications)

   The focus of this work is on the problem of the future waste to be generated by the decom-missioning of wind farms and especially the Fiber Reinforced Polymer (FRP) composite materials used in the wind turbine blades. The FRP composites used to manufacture the blades are not biodegradable and present severe problems with regard to waste management and their End-of-Life (EOL). The impact on polymers on the environment and society has become a major concern in many countries. With the increased awareness of the environmental impacts of climate change, decreased and more expensive natural resources, and greater global concerns for health, the barriers to FRP production and waste disposal are likely to increase. In the context of the circular economy the preferred method to manage FRP waste is to use it in new applications or processes. Recent structural analysis research conducted by the authors related to reuse of FRP composite material parts from decommissioned wind turbine blades in infrastructure applications is presented in this paper. 

   more » « less
5. ADAPTIVE REUSE OF FRP COMPOSITE WIND TURBINE BLADES FOR CIVIL INFRASTRUCTURE CONSTRUCTION

   Gentry, T.R.; Bank, L.C.; Chen, J-F.; Arias, F.; Al-Haddad, T. (July 2018, Composites in Civil Engineering CICE 2018)

   The rapid growth in wind energy technology has led to an increase in the amount of thermosetting FRP composite materials used in wind turbine blades that will need to be recycled or disposed of in the near future. Calculations show that 4.2 million tons of waste from wind blades will need to be managed globally by 2035, increasing to 16.3 million tons by 2055. Three waste management route are possible: disposal, recycling or reusing. Currently, most FRP composites taken out of service are disposal of in landfills or are incinerated. Recycling options consist of reclamation of the constituent fibers or the resins by thermo–chemical methods or recycling of small pieces of granular FRP material as filler material by cutting, shredding or grinding. Reuse options consist of reusing the entire FRP blade or large parts of the blade in new structural applications. This paper reports on the potential for reusing parts of wind turbine blades in new or retrofitted architectural and civil infrastructure projects. The paper introduces the geometry, materials, and laminates typically used in wind blades and provides a snapshot of the sizes of wind blades likely to be available from the inventory of active turbines. Because the materials and manufacturing of commercial wind blades are proprietary, generic blade geometries and materials are discussed. These come from the Sandia National Laboratory and National Renewable Energy Laboratory, in the United States, and from OPTIMAT in the European Union. The paper presents a method for generating the geometry and material properties of structural elements cut from wind blades, using the Numerical Manufacturing and Design Tool (NUMAD), published by the Sandia National Laboratory. 

   more » « less