International Journal of Sustainable Materials and Structural Systems (13 papers in press)
Compression behaviour of composite sandwich panels with corrugated core
by Nagwa Elzayady, Eltahry Elghandour
Abstract: The corrugated-core of composite structures is low-density for sandwich panels and has excellent anisotropic properties. More efforts are needed to understand the behaviour of such composites under mechanical loads. A flexible design is proposed for manufacturing polymeric composite corrugated cells to be utilised for producing a wide cellular honeycomb-like core. Unit cell specimens with varying lengths and heights have been made of woven prepreg composite (fibreglass-epoxy). Manufacturing and experimental testing have been carried out to understand the behaviour of the specimens in both linear and nonlinear stages of edgewise compression tests. The results indicated a significant increase in the stiffness and crushing force values with increasing specimen length. Stiffness was found to be height dependent while
the crushing force was not. The total energy increased strongly with the increase in length. Specific properties relative to the specimens weight are emphasised in this study. Failure modes of different conditions were discussed.
Keywords: sandwich panels; corrugated core; fibreglass; composite laminated; stiffness crushing; edgewise compression; specific stiffness; ligaments; failure mode.
Analyzing properties of concrete made with stone dust and jute fiber using response surface methodology
by Sourav Ray, Mohaiminul Haque, Minhaz Monwar Auni, Shriful Islam
Abstract: In this study, the fresh and hardened properties of concrete produced from stone dust as fine aggregate and with the incorporation of jute fibre were analysed by employing the response surface methodology. Two independent variables, i.e., cut length (015 mm) and volumetric percent of jute fibre (00.15%) and their five responses (7-day and 28-day compressive strength, 7-day and 28-day splitting tensile strength and slump value) were considered to develop statistical models. From the response surface plot, it was observed that both compressive strength and tensile strength increases with the increase of both variables. Moreover, it was observed that the maximum compressive and split tensile strength is obtained for 15 mm cut length and with the addition of 0.10% and 0.15% jute fibre respectively. Furthermore, the slump values show a declining trend with the increase of both variables. Finally, the probabilistic models have been found statistically significant from the analysis of variance.
Keywords: jute fibre; stone dust; response surface; compressive strength; split tensile strength; slump.
Comparison between honeycomb and composite corrugated cores in sandwich panels under compression loading
by Eltahry Elghandour, Nagwa Elzayady
Abstract: The study is to evaluate the compression properties of the polymeric composite corrugated-core sandwich structure against the honeycomb-core structure. The skin facings are from the prepreg carbon fibre composite laminate, while the core is made of different materials. Four core types are suggested; carbon fibre corrugated-core, fibreglass corrugated-core, Nomex honeycomb-core, and Kevlar honeycomb-core. The study is based on an experimental work of edgewise compression testing, and the comparison between alternatives are based on the specific properties -to-weight ratio. The analysed results prove there is superior compression capacity of the polymeric composite corrugated-core sandwich members to the honeycomb-core members, in particular in the nonlinear stage of compression test. The bonded surface between the honeycomb structure and the skins is often less than that of the corrugated profile for the same sandwich panel sizes. This contact area between the core and skin facings play an important role in carrying load mechanism.
Keywords: corrugation core; honeycomb core; sandwich structure; edgewise compression; aerospace application.
Numerical Analysis Study to Validate Experimental Vibration Results of CubeSats
by Pedro Rivera, Eltahry Elghandour, Xi Wu
Abstract: CubeSats are cost-effective nanosatellites that undergo dynamic testing for launch qualification (NASA, 2013). The work presented here recreates a vibration test setup using Finite Element Analysis (FEA) in order to predict and validate the dynamic response of a CubeSat test assembly. A Poly Picosatellite Orbital Deployer (P-Pod) is used as the housing and ejection mechanism for CubeSats. For modeling purposes however, a simplified P-Pod (test pod) was used, along with a mass model to represent a CubeSat. Sine sweep and random vibration tests were performed for the test pod and mass model. CAD geometry and material properties were imported into the FEA solver Abaqus to analyze the modes, natural frequencies, and damped response of the CubeSat assemblies. Comparing the FEA results to experimental data, the first six natural frequencies of the test pod were generated with an average 7% error and an average 4% error for the first eight modes of the test pod with mass model assembly. The validated FEA template was then applied to CubeSat CPX, a concept design structure used to demonstrate the application of the FEA models developed in this work.
Keywords: CubeSat; Nano-satellite; Finite Element Analysis; Vibration data comparison; FEA model validation; Dynamic response prediction.
Damage reduction countermeasures for short span bridges focusing on restorability of structural joints
by Teruhiko Yoda, Weiwei Lin
Abstract: Disaster-related losses cause short- as well as long-term adverse effects on econ-omy, society, health, culture and the environment. Then, resilient infrastructure with less cost will be hoped for. The resilience of infrastructure and built envi-ronment are long-term issues. This means cooperation is required with the gov-ernment, municipalities and other related organs to ensure network continuity so that the different organizations can cooperate smoothly. In Japan, the events of March 11, 2011 highlighted the need for the related government agencies, munic-ipalities, research organizations and universities to work together in formulating and implementing a holistic and comprehensive policy approach for damage re-duction countermeasures. In this paper, damage reduction countermeasures for bridge structures are presented, with a view to earthquakes, tsunamis, floods, de-terioration.
Keywords: Bridge superstructure; Damage reduction; Earthquake; Tsunami; Flood; Resilience; Deterioration of bridges; Performance-based design.
Present and future resilience research driven by science and technology
by Marco Domaneschi, Gian Paolo Cimellaro, Lili Xie, Michel Bruneau, Zhishen Wu, Max Didier, Mohammad Noori, Aftab Mufti, Xilin Lu, Xinzheng Lu, Jinpin Ou, Shamim Sheikh, Ying Zhou, Teruhiko Yoda, Ertugrul Taciroglu, Ivo Häring, Anastasios Sextos
Abstract: Community resilience against major disasters is a multidisciplinary research field that garners an ever-increasing interest worldwide. This paper provides summaries of the discussions held on the subject matter and the research outcomes presented during the Second Resilience Workshop in Nanjing and Shanghai. It, thus, offers a community view of present work and future research directions identified by the workshop participants who hail from Asiaincluding China, Japan, and Korea, Europe, and the Americas.
Keywords: Community resilience; Critical Infrastructure; Regional Assessment.
From event to performance function-based resilience analysis and improvement processes for more sustainable systems
by Ivo Häring, Jörg Finger, Mirjam Fehling-Kaschek, Kai Fischer, Georg Vogelbacher, Katja Faist, Werner Riedel, Benjamin Scharte, Katharina Ross, Elena-Maria Restayn, Alexander Stolz, Tobias Leismann, Stefan Hiermaier
Abstract: The rising variety of threats due to increasing complexity, interconnected-ness and intelligence of socio technical systems as well as increasing ex-tremes of threats, e.g., due to stronger natural threats and more sophisticat-ed terroristic events, ask for improved approaches for overall risk control and resilience enhancement. This holds in particular for critical infrastructures and public spaces. The present paper reviews and discusses advanced ap-proaches for several example domains: risk and resilience quantification of single explosions in civil contexts; susceptibility, vulnerability, averaged risk and recovery analysis in case of terroristic events in urban public spaces; quantification of cascading effects in coupled supply grids; questionnaire-based scoring approach for critical infrastructures for overall risk control and resilience enhancement; and a semi-quantitative tabular resilience analysis and management approach applied to telecommunication networks. In each case, the main process and its steps, selected typical methods for process steps and results of the approach are summarized. It is shown that most of the schemes focus on risk event assessment for single or multiple threat or disruptive events only. However, more recent approaches ask for the identi-fication, determination and use of time-dependent system performance (ser-vice) functions and their assessment in case of disruptions. While classical risk management identifies objectives of stakeholders and quantifies risk events countering these objectives, time-dependent system (non) perfor-mance function resilience assessment is argued to allow a more direct quan-tification of overall risk control objectives, since it assesses main system ser-vice functions before, during and post disruptions. Also, it is more suitable for communication with the public, management, and for dashboard mobile visualization. Hence, in each case, it is shown how to link more classical risk analysis approaches and results with time-dependent system performance function risk and resilience quantification.
Keywords: Resilience and risk quantification and management; System (non) performance function; Explosive quantitative risk analysis; Terrorism susceptibility; vulner-ability and averaged risk and resilience analysis; Coupled supply grid analy-sis; Semi-quantitative residence analytics; Tabular telecommunication grid risk and resilience analysis.
A Strategic Framework for Resilient and Sustainable Urban Infrastructure Systems An Overview, Model-ing, Design and Assessment
by Wael A. Altabey, Mohammad Noori, Ying Zhao
Abstract: Undoubtedly, infrastructure is the backbone of the worlds economies. This in-clude transportation networks, such as bridges, tunnels, subways, railways, ship yard cranes; water delivery, utilities, dams, various pipeline networks, power transmission, communication network, government centers, and large business centers. Resilience research for infrastructure networks covers multi-faceted and multidisciplinary domains encompassing risk analysis, uncertainty quantification, risk and reliability analysis in design, vulnerability mitigation, performance im-provement, and sustainable development, to cite a fee examples. Some of the in-herent attributes of resilience are diversity, efficiency, adaptability, and cohesion. Despite the importance of this topic, a holistic framework for creating resilient in-frastructure systems regarding component, system and system-of-systems levels has not been established by incorporating technical, organizational, economic, so-cial and environmental and ecological dimensions. In this paper, basic concepts of resilience, ecology and sustainability are introduced first. Then associated per-formance metrics and interdependency of critical infrastructure systems are pre-sented and discussed. Moreover, the importance of big data (BD) and data min-ing (DM), as emerging themes in this field, is discussed. Other relevant issues such as how to foster decision-making and accountability to plan for any expan-sion in resilience services, resources, and the associated performance metrics and interdependency of critical infrastructure systems are presented. It is the recom-mendation of this study that due to the difficulty and complexity of resilience, and its definitional ambiguity, the ability to assess such a concept helps to bridge the gap between theory and application, and between the academic and the policy cir-cles. A framework for creating resilient, ecological and sustainable infrastructure systems is also proposed, as a recommendation, in a more holistic and compre-hensive way. This framework is shown promising for its effectiveness and effi-ciency in modeling, designing and assessing system resilience. Finally, the re-view reveals that several opportunities are available for applying the concept of resilience in infrastructure; however, there are still many issues and challenges to be addressed in order to achieve a better utilization of this methodology, and a new relevant evaluation approach for the resilience of infrastructure systems and their evaluatiohs.
Keywords: Infrastructure Systems; Resilience Metrics; Interdependency; Resilience Capacity; Resilient; Ecological and Sustainable Systems; Resilience assessing Method.
Assessment and prediction of mechanical strength of jute fiber reinforced recycled aggregate concrete
by Mushtaq Ahmed, Md Ashiqur Rahman, Abidur Rahman
Abstract: A large amount of construction and demolished waste are generated all over the world daily, particularly in developing countries like Bangladesh due to rapid urbanization and construction works. To manage this waste properly, recycled aggregate concrete (RAC) might draw a sustainable and economic option of construction work. However, concrete shows a very weak response in tension. Using the natural fiber in concrete as reinforcement can improve the strength and ductility of concrete. This study investigates the mechanical strength performance of RAC using Jute Fiber with the full replacement of natural coarse aggregate. Two concrete mix proportion (1:1.5:3 and 1:2:4), four different water- cement ratios (W/C) (0.4, 0.45, 0.5 and 0.55) and four types of jute percentages by weight of the cement (0%, 1%, 2% and 3%) having 10 mm length were considered to inspect the 28 days compressive strength and splitting tensile strength behavior of jute fiber reinforced recycled aggregate concrete (JFRRAC). It is evidenced that the mix proportion of 1:1.5:3, W/C ratio of 0.45 and jute percentage of 1% have shown 19.30 MPa and 2.48 MPa of compressive strength and splitting tensile strength respectively which is maximum and quite satisfactory comparing with natural aggregate concrete. Strength prediction equations also have been developed in this study by multivariable linear regression analysis to predict the strength of JFRRAC.
Keywords: Recycled Aggregate Concrete; Jute Fiber; Splitting Tensile Strength; Fiber Reinforced Concrete; Demolished Waste.
Structural Health Monitoring of Composites from Carbon Nanotube (CNT) Coated E-Glass Fiber
by Eltahry Elghandour, Amro El Badawy, Ashraf Elbarbary, Sidney Wong, Omar Dwidar, Sergio Rafael Rodriguez
Abstract: Composite materials are extensively used as an advanced engineering material, particularly in aerospace, automotive, and buildings industries due to their superior properties such as high strength to weight ratios and resistance to corrosion. As composite materials are rapidly replacing traditional materials in aircraft manufacturing, improved methods of identifying damage and critical failure are in development. One of the most commonly used procedures utilizes a health monitoring system that relies on transducers to monitor transmitted waves generated by ultrasonics. By replacing this method with a nanotechnology-based one, it is possible to efficiently detect damage without the time-extensive process of scanning the structure. This research investigated the development of a nanomaterial-based sensor for health monitoring of composite structures. To develop the sensor, carbon nanotube/epoxy mixture was coated on a strand of E-glass fibre to be adhered onto a fiberglass composite specimen. The selection of E-glass fibre and fibreglass plate was largely due to its electrical insulating properties to demonstrate that the carbon nanotube is driving the sensing capabilities through its highly conductive nature. In addition, by adhering the coated E-glass fiber to a fibreglass coupon, the homogeneity and material properties were approximately maintained. Tensile testing of the specimen provided data on the actual strain which was correlated with the experimental differential resistances measured by a multimeter, both at the same specified tensile loading conditions. The experimental resistance data was calibrated with the actual strain data collected. Ultimately, the experimental sensors created a sample of gauge factors, which represents 91.24% probability of replicating the observed range of gauge factors by using the same manufacturing procedures, providing a valid alternative and consistent method to detecting composite damage.
Keywords: Composites; Strain Gauge; Carbon Nanotubes (CNT); E-Glass Fiber; Health Monitoring System.
Special Issue on: 2nd International Workshop on Resilience Resilience in the World Share the Knowledge, See the Future, Help Communities
Resilience and Sustainability of FRP-Retrofitted Concrete Structures
by S. Mukhtar Homam, Shamim Sheikh
Abstract: Damaged, deteriorated and deficient structures can prove to be among the biggest obstructions in an otherwise resilient community. An innovative rehabilitation technique using fibre reinforced polymers (FRP) was developed to build resilience in such structures. Lab investigations found that deteriorated concrete columns sustained about 20% loss in strength and larger reduction in ductility and energy dissipating capacity as a result of corrosion induced deterioration. Experimental results showed that utilizing FRP and special grouts not only recovered but enhanced the mechanical performance of these structures.
Long-term testing in the lab and observations in the field found excellent durability in FRP and FRP-retrofitted structures. This innovative repair technique resulted in remarkable reduction in risk of deterioration and performance degradation. It was concluded that resilience can be built into deficient or damaged structures through incorporation of innovative retrofitting techniques and utilization of durable materials that are economical and superior to traditional methods.
Keywords: Glass fibre reinforced polymer; bridge column; durability; freeze thaw cycles; temperature cycles; alkali solutions; ultraviolet radiation; long term performance; coupons; single lap bond.
Special Issue on: IJSMSS 2nd International Workshop on Resilience Resilience in the World Share the Knowledge, See the Future, Help Communities
Resilience and recoverability enhancement of concrete structures
by Zhishen WU, Mohamed Fahmy
Abstract: This study addresses the importance of enhancing the recoverability of reinforced concrete (RC) structures. A summary of the efforts and achievements done by the research community to improve the recoverability of RC structures is dis-cussed. In addition, the resilience of existing structures designed according to modern codes as well as under designed structures has been evaluated. Finally, the application of fiber reinforced polymer (FRP) composites in existing and modern structures to enhance post-earthquake recoverability and to provide a new controllability-tool is discussed. Recoverability and controllability can be realized using FRP composites.
Keywords: Resilience; damage-controllable systems; FRP; RC structures.
Resilient Isolation-Structure Systems with Super-Large Displacement Friction Pendulum Bearings
by Jinping Ou, Peisong Wu, Xinchun Guan
Abstract: This paper presents a super-large displacement friction pendulum bearing (SLDFPB) and isolation system with SLDFPB. SLDFPB has one or several spherical shells of large span and large curvature radius as an integrated sliding isolation layer. Superstructure can sustain large horizontal displacement through relative sliding between large spherical shell and sliding blocks. The proposed SLDFPB has two main advantages: i) avoid damage of isolation layer during super-strong earthquakes owing to large lateral deformation capability; and ii) have better isolation effectiveness because of smaller horizontal stiffness and isolation frequency. This study also investigates mechanical property of SLDFPB including equivalent radius and equivalent friction coefficient. Suggested designed method of SLDFPB is given based on seismic mitigation and reset ability of isolation layer. Two isolation structure systems with multi isolation layers are studied. The results show that large ratio of mass and optimized parameters contributes to good control effect.
Keywords: friction pendulum bearing; sustainable structural system; isolation system; equivalent radius; equivalent friction coefficient.