Julian A. Norato

Julian A. Norato
University of Connecticut | UConn · Department of Mechanical Engineering

PhD in Mechanical Engineering

About

58
Publications
13,227
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,116
Citations
Citations since 2016
44 Research Items
1804 Citations
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
Additional affiliations
August 2014 - present
University of Connecticut
Position
  • Professor (Assistant)
August 2014 - present
University of Connecticut
Position
  • Professor (Assistant)
Description
  • - Design with the Finite Element Method - Principles of Optimum Design
January 2014 - May 2014
University of Illinois, Urbana-Champaign
Position
  • Visiting Lecturer
Description
  • Nonlinear Solid Mechanical Design
Education
January 2004 - May 2005
University of Illinois, Urbana-Champaign
Field of study
  • Mechanical Engineering
August 1999 - December 2003
University of Illinois, Urbana-Champaign
Field of study
  • Mechanical Engineering
January 1992 - December 1997
National University of Colombia
Field of study
  • Mechanical Engineering

Publications

Publications (58)
Conference Paper
This work introduces a computational method for designing ceramic scaffolds fabricated via direct ink writing (DIW) for maximum bone growth, whereby the deposited rods are curvilinear. A mechanobiological model of bone adaptation is used to compute bone growth into the scaffold, taking into account the shape of the defect, the applied loading, and...
Article
Full-text available
This paper introduces a novel method for stress-constrained topology optimization in which the stress constraint is a differentiable approximation of the maximum element stress violation in the structure. The element stress violation is given by a differentiable rectifier function. A key feature of the proposed method is its ability to render desig...
Article
Wind power is one of the main sources of renewable energy. New applications of this technology are currently under development through small vertical axis wind turbines, allowing energy production in small spaces even at low wind speeds. Therefore, creating an effective turbine design methodology tailored to these operating conditions has been the...
Article
Full-text available
This work introduces a topology optimization method for the design of structures composed of fiber-reinforced, rectangular plates. Each of the plates has a predetermined, non-designable reinforcement, and the proposed method determines an optimal layout of the plates within a prescribed three-dimensional region. A plate is modeled using a homogeneo...
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-2245.vid This work aims to address the challenging problem of buckling in topology optimization of structures made of geometric components. Specifically, the structure may be composed entirely from the union of bar or plate geometric primitives, or these primitives may reinforce a fixed struct...
Article
Full-text available
This work presents a topology optimization method for the design of programmable lattice materials whose struts can be activated/deactivated by some actuation mechanism. The proposed method simultaneously determines the spatial layout of struts in the unit cell, and two or more programs corresponding to the open/close states of the struts in order...
Conference Paper
This work presents a topology optimization method for the design of structures composed exclusively of rectangular plates made of a predetermined, generally anisotropic material. The geometry projection method is employed to map the highlevel geometry and material properties to a fixed grid for the analysis, thus circumventing the need to re-mesh u...
Article
This work introduces a computational method for designing bone scaffolds for maximum bone growth. A mechanobiological model of bone adaptation is used to compute the bone growth, taking into account the shape of the defect, the applied loading, and the existing density distribution of the bone in which the scaffold has been implanted. Numerical hom...
Article
Full-text available
This work presents a topology optimization method for design of architected truss lattices made of anisotropic struts. Employing anisotropic materials for the lattice struts can result in better effective properties than those that can be obtained for a lattice in which each strut is made of a single isotropic material, but different struts may be...
Article
We present a novel topology optimization (TO) method for the design of structures composed of bars that are made of an orthotropic, fiber-reinforced material. The designs generated under this framework tailor the layout of the fiber-reinforced bars to maximize the stiffness of the structure for a fixed amount of material. The proposed method extend...
Conference Paper
This work introduces a topology optimization technique for the design of fail-safe structures made of geometric components. Specifically, the structure is made of the union of bar or plate geometric primitives. The geometry projection method is employed to smoothly map the geometric parameters that describe the primitives onto a continuous density...
Article
This paper presents a topology optimization formulation for frequency-domain dynamics to reduce solution dependence upon initial guess and considered loading conditions. Due to resonance phenomena in undamped steady-state dynamics, objectives measuring dynamic response possess many local minima that may represent poor solutions to a design problem,...
Article
Full-text available
In this review we identify a new category of methods for implementing and solving structural optimization problems that has emerged over the last 20 years, which we propose to call feature-mapping methods. The two defining aspects of these methods are that the design is parameterized by a high-level geometric description and that features are mappe...
Conference Paper
This work introduces a topology optimization method for the design of structures composed of rectangular plates each of which is made of a predetermined anisotropic material. This work builds upon the geometry projection method with two notable additions. First, a novel geometric parameterization of plates represented by offset surfaces is formulat...
Article
This work introduces an Adaptive Mesh Refinement (AMR) strategy for the topology optimization of structures made of discrete geometric components using the geometry projection method. Practical structures made of geometric shapes such as bars and plates typically exhibit low volume fractions with respect to the volume of the design region they occu...
Article
Full-text available
This work introduces a MATLAB code to perform the topology optimization of structures made of bars using the geometry projection method. The primary objective of this code is to make available to the structural optimization community a simple implementation of the geometry projection method that illustrates the formulation and makes it possible to...
Article
A major limitation in extrusion-based bioprinting is the lack of direct process control, which limits the accuracy and design complexity of printed constructs. The lack of direct process control results in a number of defects that can influence the functional and mechanical outcomes of the fabricated structures. The machine axes motion cannot be re...
Preprint
Full-text available
This work presents a computational method for the design of architected truss lattice materials where each strut can be made of one of a set of available materials. We design the lattices to extremize effective properties. As customary in topology optimization, we design a periodic unit cell of the lattice and obtain the effective properties via nu...
Preprint
Full-text available
In this review we identify a new category of structural optimization methods that has emerged over the last 20 years, which we propose to call feature-mapping methods. The two defining aspects of these methods are that the design is parameterized by a high-level geometric description and that features are mapped onto a fixed grid for analysis. The...
Preprint
Full-text available
In this review we identify a new category of structural optimization methods that has emerged over the last 20 years, which we propose to call feature-mapping methods. The two defining aspects of these methods are that the design is parameterized by a high-level geometric description and that features are mapped onto a fixed grid for analysis. The...
Preprint
Full-text available
This work presents a computational method for the design of architected truss lattice materials where each strut can be made of one of a set of available materials. We design the lattices to extremize effective properties. As customary in topology optimization, we design a periodic unit cell of the lattice and obtain the effective properties via nu...
Preprint
Full-text available
This work introduces an Adaptive Mesh Refinement (AMR) strategy for the topology optimization of structures made of discrete geometric components using the geometry projection method. Practical structures made of geometric shapes such as bars and plates typically exhibit low volume fractions with respect to the volume of the design region they occu...
Conference Paper
In this paper, we present a method for multi-material topology optimization of lattice structures for maximum bulk modulus. Unlike ground structure approaches that employ 1-d finite elements such as bars and beams to design periodic lattices, we employ a 3-d representation where each lattice bar is described as a cylinder. To accommodate the 3-d ba...
Article
Fatigue resistance is an important structural design criterion. In this work, we present a method for the topology optimization of structures subject to non-proportional cyclic loading with regard to fatigue criteria. The non-proportionality of the loading leads to a significant increase in computational cost with respect to topology optimization m...
Article
Full-text available
This article provides a comprehensive review of recent research efforts on the development and characterization of sandwich structures with corrugated, honeycomb, and foam cores. The topics discussed in this review article include aspects of core‐face bonding and reinforcement, enhancement of core mechanical properties and panel performance (includ...
Conference Paper
Topology optimization problems are typically non-convex, and as such, multiple local minima exist. Depending on the initial design, the type of optimization algorithm and the optimization parameters, gradient-based optimizers converge to one of those minima. Unfortunately, these minima can be highly suboptimal, particularly when the structural resp...
Article
Full-text available
This work presents a method for the continuum-based topology optimization of structures whereby the structure is represented by the union of supershapes. Supershapes are an extension of superellipses that can exhibit variable symmetry as well as asymmetry and that can describe through a single equation, the so-called superformula, a wide variety of...
Article
We present a new method for the simultaneous topology optimization and material selection of structures made by the union of discrete geometric components, where each component is made of one of multiple available materials. Our approach is based on the geometry projection method, whereby an analytical description of the geometric components is smo...
Article
Well-designed honeycomb sandwich panels are known to have superior blast performance compared to their corresponding solid panel of the same mass. However, the residual structural capacity of honeycomb sandwich panels and their blast resilience has not been systematically studied. Here, we investigate the structural behavior of all-metal honeycomb...
Article
We constructed a new class of three-dimensional cellular metamaterials by connecting planar structure with anti-chiral topology. This was achieved by introducing a unique node design for connecting planar materials to enable constructing a three-dimensional architecture. This node design is based on linking the circular elements of the anti-chiral...
Article
Single-curvature plates are commonly encountered in mechanical and civil structures. In this paper, we introduce a topology optimization method for the stiffness-based design of structures made of curved plates with fixed thickness. The geometry of each curved plate is analytically and explicitly represented by its location, orientation, dimension...
Article
This paper proposes a level set method to solve minimum stress and stress-constrained shape and topology optimization problems. The method solves a sub-optimization problem every iteration to obtain optimal boundary velocities. A p-norm stress functional is used to aggregate stresses in a single constraint. The shape sensitivity function is derived...
Article
Bone scaffold porosity and stiffness play a critical role in the success of critical-size bone defect rehabilitation. In this work, we present a computational procedure to design ceramic bone scaffolds to provide adequate mechanical support and foster bone healing. The scaffolds considered in our study consist of a lattice of curved rods fabricated...
Article
In this paper, we introduce a framework for the stress-based topology optimization of structures made by the assembly of discrete geometric components, such as bars and plates, that are described by explicit geometry representations. To circumvent re-meshing upon design changes, we employ the geometry projection method to smoothly map the geometric...
Article
The stiffness of plate structures can be significantly improved by adding reinforcing ribs. In this paper, we are concerned with the stiffening of panels using ribs made of constantthickness plates. These ribs are common in, for example, the reinforcement of ship hulls, aircraft wings, pressure vessels, and storage tanks. Here, we present a method...
Article
Full-text available
We introduce a topology optimization method for the stiffness-based design of structures made of plates. Our method renders topologies made distinctly of plates, thereby producing designs that better conform to manufacturing processes tailored to plate structures, such as those that employ stock plates that are cut and joined by various means. To f...
Conference Paper
The stiffness of plate structures can be significantly improved by adding reinforcing ribs. In this paper, we are in particular concerned with stiffening of panels using ribs made of constant-thickness plates that may be, for example, welded to the panel. These ribs are common in, for example, the reinforcement of ship hulls, aircraft wings, pressu...
Article
This article describes a method for the continuum-based topology optimization of structures made of discrete elements. In particular, we examine the optimization of linearly elastic planar structures made of bars of fixed width and semicircular ends. The design space for the optimization consists of the endpoint locations of the bar’s medial axes a...
Conference Paper
This paper presents an optimization method for optimally distributing short fibers of variable length for the reinforcement of structural components for stiffness. Unlike standard density-based and level set topology optimization methods that generally render material distributions with variable member size, the proposed method projects an explicit...
Article
This article describes an efficient method for the shape optimization of axisymmetric structures under asymmetric loads. Our method employs the semi-analytical method for both the primal and adjoint sensitivity analyses to convert the three-dimensional problem into a more manageable two-dimensional problem. By using the Kronecker product and the ma...
Conference Paper
We present a methodology to design structures with fixed-width and fixed-thickness beams using continuum-based topology optimization. The proposed methodology projects the geometry of rectangular bars onto the analysis grid, whereby each bar is parameterized by its end points, which are the design variables for the optimization. We present a simple...
Article
We derive a cellular solids approach to the design of bone scaffolds for stiffness and pore size. Specifically, we focus on scaffolds made of stacked, alternating, orthogonal layers of hydroxyapatite rods, such as those obtained via micro-robotic deposition, and aim to determine the rod diameter, spacing and overlap required to obtain specified ela...
Article
We perform reliability-based topology optimization by combining reliability analysis and material distribution topology design methods to design linear elastic structures subject to random inputs, such as random loadings. Both component reliability and system reliability are considered. In component reliability, we satisfy numerous probabilistic co...
Article
We propose an effective algorithm to resolve the stress-constrained topology optimization problem. Our procedure combines a density filter for length scale control, the solid isotropic material with penalization (SIMP) to generate black-and-white designs, a SIMP-motivated stress definition to resolve the stress singularity phenomenon, and a global/...
Article
We propose a fictitious domain method for topology optimization in which a level set of the topological derivative field for the cost function identifies the boundary of the optimal design. We describe a fixed-point iteration scheme that implements this optimality criterion subject to a volumetric resource constraint. A smooth and consistent projec...
Article
We present a new method for shape optimization that uses an analytical description of the varying design geometry as the control in the optimization problem. A straightforward filtering technique projects the design geometry onto a fictitious analysis domain to support simplified response and sensitivity analysis. However, the analytical geometry m...
Article
1. Abstract We perform reliability-based topology optimization by combining reliability analysis and material dis- tribution topology design methods to design linear elastic structures subject to random inputs, such as random loadings. In the optimization the structure volume is minimized subject to probabilistic per- formance constraints. Both com...
Article
1. Abstract We propose a fictitious domain method for topology optimization in which the boundary of the optimal design is identified by a level set of the topological derivative field of the objective function that satisfies a given resource constraint. The response analysis employs a smooth and consistent projection of the geometry onto the ficti...

Network

Cited By