Ciro Soto - Academia.edu (original) (raw)

Papers by Ciro Soto

Topology Optimization of Structures and Composite Continua, 2000

In this study, a 2D lattice model is proposed to approximate the relevant behavior of a continuum... more In this study, a 2D lattice model is proposed to approximate the relevant behavior of a continuum structure during an impact event. An optimization problem is posed to minimize a measure of the acceleration while constraining the displacement at special points in the structure. Design variables are associated with the material properties of unit cells of the lattice. A solution strategy whereby the optimization takes place inside the time integration scheme used for the analysis proved to be an efficient way to solve the problem. An example illustrates the problem and the difficulties yet to be addressed.

A benefit analysis system allows a user to compare the energy consumption between a first electri... more A benefit analysis system allows a user to compare the energy consumption between a first electric vehicle and a second vehicle. A data collector receives user driving characteristics. A parameter calculation module determines a peak parameter, a width parameter, a weighting factor, a scaling factor, and a frequency parameter in response to the user driving characteristics. An analyzer responsive to the parameters from the parameter calculation module to generate respective energy consumption results for the first and the second vehicle. The analyzer provides a personal drive chain distribution is as a composite function having a common component, which is defined by the peak parameter and the width parameter, and a non-common component which is defined by the scaling factor. The composite function combines the ordinary component and the non-common component in accordance with the weighting factor. The analyzer determines the power consumption results in response to the personal dri...

ABSTRACT A new formulation of the problem of computing the layout of reinforcement of Reissner-Mi... more ABSTRACT A new formulation of the problem of computing the layout of reinforcement of Reissner-Mindlin plates for minimum compliance is presented. Bending and transverse shear stiffness properties of plates with an arbitrary but finite number of local rib directions and widths are computed using standard homogenization techniques. These properties are then expressed in terms of only four variables that fully describe the anisotropy of the plate. The optimization problem is solved in two stages consisting of a local, four-dimensional maximization problem, where a given amount of material is optimally allocated into an arbitrary number of fine scale stiffeners of different widths and orientations, and a global one-dimensional optimization problem, where the optimum spatial layout of material is determined. A discussion of implementation issues is included and an example is solved to illustrate the approach.

Crashworthiness, Occupant Protection and Biomechanics in Transportation Systems

This paper presents a new formulation for the structural topology optimization problem under cras... more This paper presents a new formulation for the structural topology optimization problem under crashworthiness conditions. The objective of the optimization problem is to match levels of plastic strain and stress to prescribed values while having a weight constraint under consideration. The problem is solved by using a non-gradient based algorithm that allows to reach near to the optimum in a quick fashion. An example is presented to illustrate the optimization formulation. Results show that the formulation and algorithm are suitable for practical applications.

A new application of a homogenization method in optimal shape design is presented. Optimum reinfo... more A new application of a homogenization method in optimal shape design is presented. Optimum reinforcement of damaged structures is achieved by a simple modification of the approach presented by Bendsøe and Kikuchi [1] for optimum structural shape synthesis. The method is applied to frame structures subject to specific damages.

Volume 3: 22nd Design Automation Conference

This work deals with the problem of computing the optimum topology of structures subject to a for... more This work deals with the problem of computing the optimum topology of structures subject to a force frequency spectrum. The analysis is done in the frequency domain and the optimum topology is computed using the simplified density approach. Optimization formulation as well as the sensitivity analysis are discussed. An example showing the capabilities of the computational implementation is presented.

SAE Technical Paper Series

A brief review of different strategies for designing simultaneously the global structural topolog... more A brief review of different strategies for designing simultaneously the global structural topology and the local material properties is presented. Different treatments have been developed in the last decade to design the stiffest continuum structure using the concept of material distribution introduced in 1988 by Bends0e and Kikuchi. The comparison of such treatments shows a trend towards simplification, as expected, and also towards unification of metrics that allows the expression of design variables, objective functions, and constraints in a single basis. Numerical examples are presented to show the capabilities of the 'natural basis' treatment introduced by Taylor in 1998.

Volume 1: 30th Design Automation Conference, 2004

ABSTRACT Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Associat... more ABSTRACT Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

International Journal of Crashworthiness, 2004

ABSTRACT This paper presents a method to obtain optimum topologies of structures subject to impac... more ABSTRACT This paper presents a method to obtain optimum topologies of structures subject to impact loads that produce geometric and material nonlinear behavior, surface contact, friction, and other phenomena in shell and three-dimensional structures. The main feature of this method is an algorithm that does not use sensitivity (gradient) information and does not require large number of iterations. A criterion called prescribed plastic strain/stress is used to circumvent the lack of sensitivity information. Additionally, a controlled crash behavior (CCB) feature is included in the simulation phase allowing design engineers to prescribe an improved structural behavior. An application of this method in a vehicle front rail is presented.

International Journal of Crashworthiness

This paper presents a method to obtain optimum topologies of structures subject to impact loads t... more This paper presents a method to obtain optimum topologies of structures subject to impact loads that produce geometric and material nonlinear behavior, surface contact, friction, and other phenomena in shell and three-dimensional structures. The main feature of this method is an algorithm that does not use sensitivity (gradient) information and does not require large number of iterations. A criterion called prescribed plastic strain/stress is used to circumvent the lack of sensitivity information. Additionally, a controlled crash behavior (CCB) feature is included in the simulation phase allowing design engineers to prescribe an improved structural behavior. An application of this method in a vehicle front rail is presented.

7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 1998

Structural Optimization, 1999

A method is presented for the prediction of optimal configurations for two-materiai composite con... more A method is presented for the prediction of optimal configurations for two-materiai composite continuum structures. In the model for this method, both local properties and topology for the stiffer of the two materials are to be predicted. The properties of the second, less stiff material are specified and remain fixed. At the start of the procedure for computational solution, material composition of the structure is represented as a pure mixture of the two materials. This design becomes modified in subsequent steps into a form comprised of a skeleton of concentrated stiffer material, together with a nonoverlapping distribution of the second material to fill the original domain. Computational solutions are presented for two example design problems. A comparison among solutions for different ratios of stiffness between the two materials gives an indication of how the distribution of concentrated stiffer material varies with this factor. An example is presented as well to show how the method can be used to predict an efficient layout for rib-reinforcement of a stamped sheet metal panel.

Transportation Research Part C: Emerging Technologies, 2013

ABSTRACT The environmental and economic impact of electric vehicles (EVs) will depend on the frac... more ABSTRACT The environmental and economic impact of electric vehicles (EVs) will depend on the fraction of users that can accept an EV of a given capability, and then in turn on how those EVs are actually used. Historically, estimates of the fraction of total travel that could be electrified as a function of EV range are based on vehicle usage data for large populations of vehicles, most often the National Household Travel Survey (NHTS). Two assumptions implicit in such estimates are subject to question: (1) that any user could accept an EV as a primary vehicle and would use it for all trips within its range, and (2) that the usage patterns of any individual EV user are the same as that exhibited by entire population. The first assumption is clearly unrealistic; willingness to accept an EV is dependent on the transportation needs and alternatives readily available to each individual user. As a surrogate for a priori knowledge of individual preferences, we use a crude metric of acceptance defined as a threshold frequency of need for alternative transportation above which all users would not accept the inconvenience. To test the validity of the second assumption and better estimate market and electrification potential, we analyze roughly 1 year of usage data for each of 133 instrumented vehicles in Minneapolis–St. Paul. We find a characteristic individual usage pattern that does not resemble the average over a large number of vehicles. Using the surrogate metric of EV acceptance and a simple payback model, we show that although the market acceptance and electrification potential of EVs are severely limited by battery cost, it is possible to determine an optimal EV range. Using the same usage data and payback model, we show that plug-in hybrid electric vehicles (PHEVs) can be much more effective than all-electric vehicles in electrifying personal transportation.

8th Symposium on Multidisciplinary Analysis and Optimization, 2000

Advances in Intelligent Systems and Computing, 2013

SAE International Journal of Engines, 2011

Abstract A hybrid electric vehicle (HEV) system model, which directly simulates vehicle drive cyc... more Abstract A hybrid electric vehicle (HEV) system model, which directly simulates vehicle drive cycles with interactions among driver, environment, vehicle hardware and vehicle controls, is a critical CAE tool used through out the product development process to project HEV ...