Erick I. Saavedra Flores

• University of Santiago Chile

The prevalence of poor road conditions makes urban traffic gridlock, leading to increased travel time and disruptions in urban mobility in developing countries. In this research the Payne-Whitham (PW) model which is second-order macroscopic traffic flow model was modified by replacing the speed constant (\(\:{C}_{^\circ\:}\)) with a novel parameter...

Humans are the only species who generate waste materials that cannot be broken down by natural processes. The ideal solution to this waste problem would be to employ only compostable materials. Biodegradable materials play a key role in creating a safer and greener world. Biodegradability is the gift that keeps on giving, in the sense of creating a...

Recent and past studies mainly focus on reducing the dead weight of structure; therefore, they considered lightweight aggregate concrete (LWAC) which reduces the dead weight but also affects the strength parameters. Therefore, the current study aims to use varied steel wire meshes to investigate the effects of LWAC on mechanical properties. Three t...

In recent years, wood has gained important significance in construction, with several developments and research conducted. Despite this, some species show scarce dedicated research on the mechanical behavior and data about material parameters is limited. Timber exhibits variable mechanical properties influenced by several factors. Particularly, whe...

Timber, a fascinating and versatile material, has been used for centuries in construction, furniture, and various other applications. The intricate and diverse structure of timber, spanning multiple length scales, presents challenges in developing accurate numerical models that capture its macroscopic behavior. To overcome this challenge, multiscal...

The behavior of wood when is subjected to radial compression is characteristic of regular honeycomb structures and four stages can be distinguished: elastic response, elastic micro-buckling, plateau stage and densification. Hence the wood cell collapse is a gradual process. However, significant non-linearities such as large deformations, cell wall...

The behavior of wood when is subjected to radial compression is also characteristic of regular honeycomb structures and, therefore, four stages can be distinguished: elastic response, elastic micro-buckling, plateau stage and densification. i.e., the wood cell collapse is a gradual process. However, significant non-linearities such as large deforma...

Concrete technology is adopted worldwide in construction due to its effectiveness, performance, and price benefits. Subsequently, it needs to be an eco-friendly, sustainable, and energy-efficient material. This is achieved by replacing or adding energy-efficient concrete materials from industries, such as ground granulated blast furnace slag, steel...

Steel–concrete composite systems are an efficient alternative to mid- and high-rise building structures because of their high strength-to-weight ratio when compared to traditional concrete or steel constructive systems. Nevertheless, composite structural systems are susceptible to damage due to, for example, deficient construction processes, errors...

This paper represents a first attempt to study the feasibility of using shear wave (SW) ultrasonic probes as pump-wave sources in concrete microcrack detection and monitoring by Nonlinear Ultrasonic Coda Wave Interferometry (NCWI). The premise behind our study is that the nonlinear elastic hysteretic behavior at microcracks may depend on their orie...

Copper slag (CS) is produced during the smelting process to separate copper from copper ore. The object of the experimental research is to find the optimum percentage of CS and PPF volume fraction when CS replaces fine aggregate, and PPF volume fraction when subjected to impact loading. Copper slag was incorporated as 20%, 40%, 60%, 80% and 100% wi...

In the last decades the use of wood as a construction material has been steadily increasing. Among the main reasons behind this, are its renewable resource nature and its low environmental footprint. In this context, one of the main challenges faced by engineers during the design process is the knowledge and characterization of wood’s thermo-mechan...

The use of the combination of ultrafine rice husk ash (RHA) and nano silica (NS) enhances the compactness of hardened concrete, but there is still a lack of studies that address the effects of NS and RHA on the workability, mechanical properties and pore microstructure of concrete. This study mainly aims to investigate the influence of the pore siz...

En este trabajo se presenta los resultados obtenidos del análisis micro-estructural de la madera sometida a compresión radial. Para ello, se realiza un análisis del comportamiento de estructuras regulares sometidas a compresión en el plano confinadas en una caja, incrementando el número de celdas. De esta manera, es posible caracterizar el comporta...

Citation: Arularasi, V.; Thamilselvi, P.; Avudaiappan, S.; Saavedra Flores, E.I.; Amran, M.; Fediuk, R.; Vatin, N.; Karelina, M. Rheological Behavior and Strength Characteristics of Cement Paste and Mortar with Fly Ash and GGBS Admixtures. Sustainability 2021, 13, 9600. https://

In general, most highway bridges are constructed using prestressed concrete or steel girders. Mechanical joints are provided at the end of each span, to allow for the expansion of the bridge deck due to shrinkage of concrete, thermal effects, and deflections, among others. Smooth riding ability, low noise, wear resistance, and water tightness shoul...

This paper presents a parametric study on the aeroelasticity of cantilever wings equipped with Flared Hinge Folding Wingtips (FHFWTs). The finite element method is utilized to develop a computational, low-fidelity aeroelastic model. The wing structure is modelled using Euler–Bernoulli beam elements, and unsteady Theodorsen’s aerodynamic strip Theor...

Concrete pavements for underground mining are in service under very aggressive exposure conditions (heavy loads and chemical attacks), which reduce their service life and affect mining productivity. Aiming to improve the concrete's performance, the combined use of silica fume, nanosilica, and polypropylene fibers was investigated. While each of the...

To find the energy required during the mixing process of self-compacting concrete in a ready-mixed concrete plant and correlate the results with the yield stress of concrete. Power consumption required during the mixing of concrete is measured with a wattmeter connected to the mixing unit’s power supply. A coaxial cylinder viscometer is used to mea...

Due to their sustainability as well as physical and mechanical performance, different natural fibers, both vegetal and animal fibers, have been successfully used in adobe mixtures (AMs) to enhance properties such as cracking control, flexural toughness and water erosion resistance, among others. However, the use of jute fibers (JFs), one of the mos...

An experimental investigation is performed on various cold-formed profiled sheets to study the connection behavior of composite deck slab actions using bolted shear connectors. Various profiles like dovetailed (or) re-entrant profiles, rectangular profiles and trapezoidal profiles are used in the present investigation. This experimental investigati...

This paper investigates the effect of sisal fiber addition on fresh ,mechanical properties of self compacting concrete(SCC) and flexural performance of fiber reinforced RC beams made with mineral admixtures like Meta Kaolin (MK) and Fly Ash (FA)which is an industrial waste. The mixes were prepared by varying MK content from 5% to 15% with 5% increm...

In this paper, a multi-scale modelling strategy is proposed to investigate the creep behaviour of reinforced concrete structures. A Mean Field homogenisation procedure is adopted to compute the overall response of a high-strength concrete made of limestone inclusions embedded in a cement paste matrix. Finite element models of beams subjected to sus...

Moire pattern arises from the lattice mismatch between two different nanosheets. The discovery of the Moire pattern has resulted in breakthrough properties in 2D carbon-based nanostructures such as graphene. Here we investigate the impact of a Moire pattern on mechanical properties of bi-layer 2D nanosheets. In particular, buckling instability of 2...

Graphene and its associated nanostructures (GANS) have been widely investigated by means of experimental and numerical approaches over the last decade. GANS and GANS reinforced composite materials show exceptional promise towards superior mechanical and thermal properties along with limitless opportunity to tailor, control, design, modify and manip...

Seismic hazard assessment of earthquake prone terrain is estimated in numerous ways for civil underground structures such as tunnels which receives little attention on the seismic zones of the country. The resemblance of the past behaviour of earthquake is seen in the present seismotectonic block, and this is considered for this study. With this, t...

Finite element (FE) model updating aims to minimize the discrepancy between measured and FE-predicted responses of instrumented structural systems. In the last decades, significant efforts have focused on linear FE models, including recent studies investigating applications with large models (i.e., models with many degrees-of-freedom) and/or models...

In this study, an experimental program for testing steel concrete composite slabs subjected to symmetrical double line loads has been carried out to investigate the longitudinal shear bond behaviour. Different configurations of steel concrete composite slabs with and without embossments were studied. The flexural characteristics, ultimate strength...

Los bloques de adobe son un material de construcción sustentable y de bajo costo, pero también se caracterizan por sus bajas resistencias mecánicas y a la erosión debido a agua. Por a lo anterior, la estabilización de bloques de adobe con cemento es utilizada satisfactoriamente, pero el cemento es un material con un alto costo e impacto ambiental....

Corrugated panels have many potential applications in civil, echanical and aerospace engineering. The research on morphing aircraft requires the derivation of deformation limits of corrugated panels, which can be used as the constraint conditions for the design and optimisation of morphing structures. The relationship between the local and global s...

Cross-laminated timber (CLT) is a relatively new construction building system based on structural panels made of several layers of boards stacked crosswise and glued together on their faces [1]. As CLT panels are light-weight structural elements with high stiffness and strength to bending, compression and shear, they are an economically competitive...

Wood has long been an accessible material, at hand for different type of applications. It has recently undergone a renaissance thanks to exceptional properties. For instance, as a renewable material source, it has a small environmental impact, a favorable seismic performance and it can self-protect against fire. In Chile, Radiata pine has been prom...

In this work, a computational homogenization-based multiscale modeling strategy is adopted to compute the thermal conductivity of wood and to study the thermal performance of cross-laminated timber. In order to determine the thermal conductivity of wood within a multiscale modeling framework, the behavior of its microscopic constituents is investig...

In this study, steel-concrete composite slabs are subjected to symmetrical double line loads, and the prediction of longitudinal shear resistance capacity is evaluated using the shear bond mechanism or m-k procedure. The current study uses the experimental testing data with a sufficient shear span distance to predict the effect of the normal force...

In this article, a Matlab‐based software environment called Guide Silo Design (GSD) is proposed to help undergraduate students to better understand the complex phenomena involved in the analysis process of silo structures. The software is integrated with two commercial finite element softwares. These are the Open Application Programming Interface (...

Finite element (FE) model updating has emerged as a powerful technique for structural health monitoring (SHM) and damage identification (DID) of civil structures. Updating mechanics-based nonlinear FE models allows for a complete and comprehensive damage diagnosis of large and complex structures. Recursive Bayesian estimation methods, such as the U...

The recent trend towards the use of Cross-Laminated Timber (CLT) as a novel construction material in mid- and high-rise buildings has steered the research efforts into this subject over the last few years. Despite the considerable progress made on the structural response of CLT, there are still several unresolved issues related to the analysis and...

Composite steel-concrete systems are highly dependent on the behavior of the connection at the interface. Generally, this connection is characterized by the load-slip curve from push-out tests. In this article, a numerical model is developed to represent the mechanical behavior of a shear stud anchor embedded in concrete. The updated approach consi...

In this work we investigate the structural response of cross-laminated timber (CLT) buildings by means of a multi-scale modelling strategy. In order to determine the mechanical properties of CLT, a computational homogenisation scheme based on the volume averaging of the stress and strain fields over a representative volume element (RVE) of material...

Single point incremental forming (SPIF) has several advantages over traditional forming, such as the high formability attainable by the material. Different hypotheses have been proposed to explain this behavior, but there is still no straightforward relation between the particular stress and strain state induced by SPIF and the material degradation...

In this work, a bottom-up multiscale modeling approach is developed to estimate the effective elastic moduli of Carbon NanoTube (CNT)-reinforced polymer composites. The homogenization process comprises two successive steps, including an atomistic-based computational model and a micromechanics approach at the nano- and micro-scales, respectively. Fi...

The Gurson-Tvergaard-Needleman (GTN) model includes several parameters of different nature. Some of them have micromechanical roots while others are strictly phenomenological. Hence, a methodology should be developed in order to obtain a robust set of parameters with both numerical and physical meaning. The material parameters of the GTN model are...

In this work we investigate the structural response of cross-laminated timber (CLT) buildings by means of a multi-scale modelling strategy. In order to determine the mechanical properties of CLT, a computational homogenisation scheme based on the volume averaging of the stress and strain fields over a representative volume element (RVE) of material...

The present work was originally carried out as a project by HVAC-R engineering students of a heat transfer undergraduate course. The main goal was to introduce to the students to the implementation of a commercial simulation tool, ANSYS/Transient thermal, to analyze a transient heat transfer process of their professional interest. Behind this goal...

This paper investigates the influence of the uncertainty in different micromechanical properties on the variability of the macroscopic response of cross-laminated timber plates, by means of a probabilistic sensitivity analysis. Cross-laminated timber plates can be modelled using a multiscale finite element approach which although suitable, suffers...

Concrete is an old and reliable material for construction. Its mechanical behavior has been widely studied and is well known. It is common to use reinforcements such as steel to improve the ductility of concrete under tension. Recently, nanomaterials have become an interesting solution to improve concrete’s mechanical behavior, creating a totally n...

The mechanics of wood is not fully understood due to the complex wood microstructure. At small scales, wood shows a complicated hierarchical structure distributed across different spatial scales. At the nanometer scale, it contains three basic constituents: cellulose, hemicellulose and lignin. These three fundamental constituents form the fiber-rei...

Concrete is an old and reliable material for construction. Its mechanical behavior has been widely studied and is well known. It is common to use reinforcements such as steel to improve the ductility of concrete under tension. Recently, nanomaterials have become an interesting solution to improve concrete's mechanical behavior, creating a totally n...

Purpose The purpose of this paper is to capture the actual structural behavior of the longest timber footbridge in Spain by means of a multi-scale model updating approach in conjunction with ambient vibration tests. Design/methodology/approach In a first stage, a numerical pre-test analysis of the full bridge is performed, using standard beam-ty...

The paper developed a new analytical solution for elastic deformation of thin rectangular functionally graded (FG) plates with in-plane stiffness (Young's modulus) variation, which has important applications in various thin-walled structures. Also the problem was solved numerically using the graded finite element method (FEM). The relevant governin...

Negative thermal expansion (NTE) and negative Poisson’s ratio (NPR) are counterintuitive material properties that have gained popularity as the focus of many recent works. However, most of the structures previously studied only exhibit NTE or NPR exclusively. One important structure that has already been shown to exhibit NPR is the re-entrant trian...

In this paper we propose a homogenisation-based four-scale model for the mechanical properties of cross-laminated timber. The spatial scales considered in this study are the wood cell-wall, the wood fibres, growth rings and the structural scale. The computational homogenisation scheme is solved sequently from the lowest to the highest level in orde...

A yield criterion for porous solids of the Gurson type is presented. This model is able to model ductile damage and fracture, dealing with material softening and strain localization. This usually leads to unwanted numerical features such as the loss of the ellipticity of equilibrium equations. The first step before dealing with these issues is for...

A porous yield criterion for porous solids of the Gurson[1] type is presented. This model is able to model ductile damage and fracture, dealing with material softening and strain localization. This usually leads to unwanted numerical features such as the loss of the ellipticity of equilibrium equations. The first step before dealing with these issu...

In this paper we investigate micro-macro mechanical relations in Palmetto wood, a natural composite, by means of a computational homogenisation-based multi-scale modeling approach. The homogenisation procedure is solved sequentially at multiple length scales by following a bottom-up approach. The proposed strategy consists of homogenising the three...

An atomistic multiscale modelling approach is used to simulate the nonlinear pullout behaviour of interlinked single walled carbon nano tubes (SWCNT) and single layer graphene sheets (SLGS) embedded in an epoxy polymer. The pullout forces have been computed for various configurations of nanocomposites (SWCNT-SWCNT, SLGS-SLGS and hybrid SLGS-SWCNT),...

With the aid of atomistic multiscale modelling and analytical approaches, buckling strength has been determined for carbon nanofibres/epoxy composite systems. Various nanofibres configurations considered are single walled carbon nano tube (SWCNT) and single layer graphene sheet (SLGS) and SLGS/SWCNT hybrid systems. Computationally, both eigen-value...

In this paper we investigate the rolling shear failure in cross-laminated timber structures by homogenisation and cohesive zone models. In order to predict the structural response, four spatial scales are interlinked within a purely kinematic multi-scale modelling framework. The constitutive description has incorporated information coming from the...

This paper is concerned to investigate the mechanical behavior of the wood cell-wall using a Finite Element-based fully-coupled Multi-scale Computational Homogenisation scheme. The approach to improve the understanding of the mechanical and physical properties of wood is through its hierarchical nature, distributed across multiple spatial scales. A...

Corrugation has long been seen as a simple and effective means of forming lightweight structures with high anisotropic behaviour, stability under buckling load and energy absorption capability. This has been exploited in diverse industrial applications and academic research. In recent years, there have been numerous innovative developments to corru...

This paper develops and models the compliant spar concept that allows the wingspan to be varied to provide roll control and enhance the operational performance for a medium altitude, long endurance (MALE) UAV. The wing semispan is split into morphing partitions and the concept may be incorporated in each partition; however, only the tip partition i...

This paper presents the optimum design of a PID controller for the Adaptive Torsion Wing (ATW) using the genetic algorithm (GA) optimiser. The ATW is a thin-wall, two-spar wingbox whose torsional stiffness can be adjusted by translating the spar webs in the chordwise direction inward and towards each. The reduction in torsional stiffness allows ext...

In this paper, we investigate the hyperelastic tensile behaviour of single layer graphene sheets (SLGSs). A one-term incompressible Ogden-type hyperelastic model is chosen to describe the mechanical response of C-C bonds. By establishing equality between the Ogden strain-energy and the variation of the Tersoff-Brenner interatomic potential, three d...

SUMMARY This paper investigates the optimal location of sensors in a timber structure when parametric uncertainty is considered in the microstructure of the material. In order to describe the proposed methodology, a timber beam is chosen for our numerical simulations. A classical sensor location methodology based on the Fisher information matrix is...

La presente investigación tiene por objeto determinar el comportamiento en fluencia de la made-ra, por medio de un procedimiento multi-escala en base a fundamentos variacionales [1]. Dicha metodología ha sido recientemente adoptada en la evaluación del criterio de fluencia de Gurson para materiales porosos [2]. El enfoque para mejorar la comprensió...

This paper investigates the relation between the uncertain mechanical properties of wood and its extensibility at the ultrastructural scale. A statistical approximation to the output of a multi-scale constitutive model is adopted to predict the extensibility of wood in the presence of parametric uncertainty. By means of this procedure, a very large...

Corrugated panels have gained considerable popularity in a range of engineering applications, particularly in morphing skin applications. The optimum design of these structures needs simple models of the corrugated panels that may be incorporated into multi-disciplinary system models. Considering the geometric and mechanical properties of the corru...

A comprehensive conceptual design study is performed to assess the potential benefits of span morphing technology and to determine its feasibility when incorporated on medium altitude long endurance unmanned air vehicles. A representative medium altitude long endurance unmanned air vehicle based on the BAE Systems Herti unmanned air vehicle was sel...

Shape memory alloys (SMAs) are a unique class of metallic materials with the ability to recover their original shape at certain characteristic temperatures (shape memory effect), even under high applied loads and large inelastic deformations, or to undergo large strains without plastic deformation or failure (super-elasticity). In this review, we d...

This paper investigates the extensibility of the wood cell-wall composite in the presence of parametric uncertainty by means of a multi-scale finite element approach. Normally, the three fundamental phases in wood, that is, cellulose, lignin and hemicellulose, present considerable scatter in their microstructure and mechanical properties. Neverthel...

The paper proposes a new modeling approach for the prediction and analysis of the mechanical properties in DNA molecules based on a hybrid atomistic-finite element continuum representation. The model takes into account of the complex geometry of the DNA strands, a structural mechanics representation of the atomic bonds existing in the molecules and...

The paper proposes a new modeling approach for the prediction and analysis of the mechanical properties in deoxyribonucleic acid (DNA) molecules based on a hybrid atomistic-finite element continuum representation. The model takes into account of the complex geometry of the DNA strands, a structural mechanics representation of the atomic bonds exist...

This note assesses the benefits of active aeroelastic structures (AAS) in enhancing flight performance and control authority. A representative AAS concept, whose torsional stiffness and shear centre position can be altered depending on the instantaneous flight condition, is employed in the wing of a medium altitude long endurance (MALE) UAV. A mult...

Coated composite corrugated panels have wide applications in engineering, especially in morphing skin applications. The optimal design of these structures requires simple models of the panels that may be incorporated into multi-disciplinary system models. Therefore equivalent structural models are required that retain the dependence on the geometri...

Vibration isolation devices are required to reduce the forcing into the supporting structure or to protect sensitive equipment from base excitation. A suspension system with a low natural frequency is required to improve isolation, but with linear supports the minimum stiffness is bounded by the static stiffness required to support the equipment. H...

This paper investigates the deformation and failure mechanisms of wood at the ultrastructural scale. At this level, wood is composed of a periodic alternation of amorphous and crystalline cellulose fractions, embedded in a soft hemicellulose-lignin matrix. The mechanical response of wood is calculated under tensile loading conditions by means of th...

The probabilistic characterisation of a frequency response function can be very valuable for structural design and control. Unfortunately, obtaining a sufficiently large sample for wide ranges of vibration can easily become unaffordable. A variety of modelling assumptions can dramatically add to the computational cost: nonproportional damping, mult...

This paper develops and models the Compliant Spar concept that allows the wing span to be varied to provide roll control and enhance the operational performance for a medium altitude long endurance (MALE) UAV. The wing semi-span is split into morphing partitions and the concept maybe incorporated in each partition; however only the tip partition is...

This article reviews the main mechanisms of stiffness variation typically found in nature. The temporal changes in stiffness may be fully or partially reversible, or completely irreversible, and can be very slow or fast in time depending on the strategy adopted to alter the mechanical properties. It is also possible to observe changes in the stiffn...

The probabilistic characterisation of a frequency response function can be very valuable for structural design and control. Unfortunately, obtaining a sufficiently large sample for wide ranges of vibration can easily become unaffordable. A variety of modelling assumptions can dramatically add to the computational cost: nonproportional damping, mult...