Soobum Lee

Soobum Lee
University of Maryland, Baltimore County | UMBC · Department of Mechanical Engineering

About

62
Publications
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1,067
Citations

Publications

Publications (62)
Article
This paper presents a new self-powered wireless failure detection method that uses different signal transmission rates from piezoelectric energy harvesters. Reliable signal transmission from a wireless sensor network has been challenging due to the power supply issue, often covered by batteries that need regular replacement. Piezoelectric energy ha...
Article
Full-text available
Due to lack of sufficient data and information in engineering practice, it is often difficult to obtain precise probability distributions of some uncertain variables and parameters in reliability-based design optimization (RBDO). In this paper, distributional probability-box (p-box) model is employed to quantify these uncertain variables and parame...
Article
This paper develops a mathematical model of a two degree of freedom piezoelectric energy harvester of which vibration is driven by disk swing motion. The proposed device converts slow mechanical rotation into piezoelectric vibration using gravity force and magnetic repelling force. The harvester consists of a disk and a piezoelectric cantilevered b...
Article
Efficient Structural Health Monitoring (SHM) could reduce operation and maintenance costs, improve longevity, and enhance safety of the performance in complex mechanical systems. Traditional sensor network for SHM relied on simple sensor behavior without considering uncertain factors from system and environment. A probabilistic sensing model is req...
Conference Paper
This paper proposes a probabilistic model for the placement of sensors that considers uncertain factors in the sensing system to find the best arrangement of sensor locations. Traditional procedures for structural health monitoring (SHM) usually rely on simplified behavior and deterministic factors from structure’s response. Incorporating the sourc...
Conference Paper
This paper presents mathematical modeling of a two degree of freedom energy harvester which converts slow mechanical rotation into piezoelectric vibration using gravity force and magnetic repelling force, for large-scale machinery monitoring such as wind turbine blades. The harvester consists of a disk with an unbalanced mass, a piezoelectric canti...
Article
This study explores the feasibility of energy harvesting from the deformation of a piezoelectric material attached on the human mandible to power an implantable medical device such as deep brain stimulator. A finite element (FE) model of the human mandible was developed and verified experimentally. A piezoelectric energy harvesting device was desig...
Article
Full-text available
This paper proposes an efficient Kriging-based subset simulation (KSS) method for hybrid reliability analysis under random and interval variables (HRA-RI) with small failure probability. In this method, Kriging metamodel is employed to replace the true performance function, and it is smartly updated based on the samples in the first and last levels...
Article
This paper presents mathematical modelling of an energy harvester that converts slow mechanical rotation into piezoelectric vibration using a small disk and a pair of magnets, for large-scale machinery monitoring applications such as wind turbine blades. The harvester consists of a piezoelectric cantilevered beam, a gravity-induced disk, and magnet...
Article
Reliability-based design optimization (RBDO) requires the evaluation of probabilistic constraints (or reliability), which can be very time consuming. Therefore, a practical solution for efficient reliability analysis is needed. The response surface method (RSM) and dimension reduction (DR) are two well-known approximation methods that construct the...
Article
Reliability-based design optimization (RBDO) aims at optimizing the design of an engineered system to minimize the design cost while satisfying reliability requirements. However, it is challenging to perform RBDO under high-dimensional uncertainty due to the often prohibitive computational burden. In this paper, we address this challenge by leverag...
Conference Paper
This paper presents mathematical modeling of an energy harvester (EH) for a wireless structure health monitoring (SHM) system in wind turbine blades. The harvester consists of a piezoelectric energy harvester (PEH) beam, a gravity-induced disk, and magnets attached to both the beam and the disk. An electromechanical model of the proposed EH is deve...
Article
This paper proposes a segmented impact-type piezoelectric energy harvester (PEH) for self-start impedance matching circuit. Generally, an oscillator in an impedance matching circuit requires a separate power supply. Considering randomness and intermittence of wind energy, a design of a smart power controller is essential for efficient and timely po...
Article
Reliability analysis involving high-dimensional, computationally expensive, highly nonlinear performance functions is a notoriously challenging problem in simulation-based design under uncertainty. In this paper, we tackle this problem by proposing a new method, high-dimensional reliability analysis (HDRA), in which a surrogate model is built to ap...
Article
This paper proposes alternating resistive impedance matching for an impact-type micro wind piezoelectric energy harvester (PEH). The proposed PEH is composed of a piezoelectric cantilever and a small wind turbine, which strikes the free end of the cantilever to generate vibrations. The motion of the cantilever is divided into two action periods, im...
Article
Full-text available
A new sequential sampling method, named sequential exploration-exploitation with dynamic trade-off (SEEDT), is proposed for reliability analysis of complex engineered systems involving high dimensionality and a wide range of reliability levels. The proposed SEEDT method is built based on the ideas of two previously developed sequential Kriging reli...
Conference Paper
This paper proposes a self-start piezoelectric energy harvesting circuit with an undervoltage-lockout (UVLO) converter for a wireless sensor network (WSN). First, a self-start circuit with mini piezoelectric energy harvester (PEH) is designed to supply the power for operation of the oscillator without battery. The experimental results show that a b...
Article
Energy harvesting (EH) technologies to power small sized electronic devices are attracting great attention. Wasted energy in a vehicle's rotating tire has a great potential to enable self-powered tire pressure monitoring sensors (TPMS). Piezoelectric type energy harvesters can be used to collect vibrational energy and power such systems. Due to the...
Conference Paper
Full-text available
In this paper we perform reliability analysis for a piezoelectric energy harvester to power the tire pressure monitoring sensor (TPMS) under various uncertainty. Reliability based design optimization (RBDO) is applied to improve the performance of the system. Wasted vibrational energy in a vehicle’s rotating tire can be exploited to enable a self-p...
Article
This paper proposes a new minimum power-loss management circuit with a quick self-start function, for effective power use from an impact-type micro wind piezoelectric energy harvester. The free tip of the piezoelectric cantilever harvester is excited by a miniaturized wind blade. A smart power management strategy is required for efficient saving an...
Article
In recent years, vibration energy harvesters have been widely studied to build self-powered wireless sensor networks for monitoring modern engineered systems. Although there has been significant research effort on different energy harvester configurations, the power output of a vibration energy harvester is known to be sensitive to various sources...
Article
Full-text available
This paper proposes a stepwise structural design methodology where the component layout and the supporting frame structure is sequentially found using global search algorithm and topology optimization. In the component layout design step, the genetic algorithm is used to handle system level multiobjective problem where the optimal locations of mult...
Conference Paper
This paper presents design optimization of an electromagnetic vibration energy harvester to improve durability and increase life cycle. The energy harvester discussed in this paper has been developed by the Korean Railroad Research Institute, as a maintenance-free power supply for a wireless sensor module that monitors rail bogie axles and bearings...
Conference Paper
Energy harvesting technology can provide a renewable, portable power source for soldiers who rely solely on battery power in the field. Electromagnetic energy harvesters scavenge energy from wasted kinematic and vibration energy in human motion. The motion of interest in this paper is vertical hip displacement during human gait that acts as a base...
Conference Paper
This paper proposes a new efficient motion conversion system which can be used in an energy harvesting system that converts wasted kinematic energy into electrical energy. In the proposed system, a reciprocating translational motion will be converted into one-directional rotational motion that spins a generator. The system will be devised with a tw...
Conference Paper
In this paper, we perform design parameter study and design optimization for a piezoelectric energy harvester considering vehicle speed variation. Initially, a FEM model using ANSYS is developed to appraise the performance of a piezoelectric harvester in a rotating tire. The energy harvester proposed here uses the vertical deformation at contact pa...
Conference Paper
This paper presents reliability-based design optimization (RBDO) and experimental validation of the purely mechanical nonlinear vibration energy harvester we recently proposed. A bi-stable characteristic was embodied with a pre-stressed curved cantilever substrate on which piezoelectric patches were laminated. The curved cantilever can be simply ma...
Article
The power output of a vibration energy harvesting device is highly sensitive to uncertainties in materials, manufacturing, and operating conditions. Although the use of a nonlinear spring (e.g., snap-through mechanism) in energy harvesting device has been reported to reduce the sensitivity of power output with respect to the excitation frequency, t...
Article
The burgeoning growth of tall buildings around the world requires novel design methodologies to resolve design challenges imposed by the enormous volume of material and energy employed during their construction and operation. To meet this upcoming social demand on tall buildings, practical and efficient design method is proposed for optimal outrigg...
Article
This paper presents a robust design framework to develop piezoelectric materials based structural sensing systems for failure diagnostics and prognostics. At first, a detectability measure is proposed to evaluate the performance of any given sensing system given various uncertainties. Thus, the censoring system design problem can be formulated to m...
Article
Vibration energy harvesting (EH) has been initiated from linear vibration principle, which utilizes a single frequency to obtain power. Unfortunately, linear energy harvesters do not yield appreciable power because of random nature of vibration in the real world. In order to overcome the weakness of linear harvesters and account for the arbitrary n...
Article
The increasing interest in mechanical systems exhibiting enhanced vibration control and shock mitigation characteristics has motivated the study of novel design approaches for the synthesis of scalable systems with passive adaptive dynamic characteristics. In this article, we present a modular design concept to synthesize passive adaptive structure...
Conference Paper
The increasing interest in engineering systems with excellent mitigation of vibration and shock has required novel design approaches which provide systems with passive adaptive performance across the different fields of engineering. In this paper we present a novel modular design concept to synthesize passive adaptive structures upon a varied loadi...
Conference Paper
This paper proposes design optimization of a mechanically decoupled six-axis F/T sensor. In order to indicate the biggest cross coupling error of a Maltese cross type F/T six-axis sensor, principal error is proposed in this paper. Locations of twenty-four strain gages are determined and four design variables are selected to solve optimization probl...
Article
A new concept design of electromagnetic energy harvester is proposed for powering a tire pressure monitoring sensor (TPMS). The thin coil strap is attached on the circumferential surface of a rim and a permanent magnet is placed on the brake caliper system. When the wheel rotates, the relative motion between the magnet and the coil generates electr...
Article
An earlier study introduced the concept of piezoelectric energy-harvesting skin (EHS) to harvest energy by attaching thin piezoelectric patches onto a vibrating skin. This paper presents a methodology for the optimum design of EHS with the use of an efficient topology optimization method referred to as the hybrid cellular automaton (HCA) algorithm....
Conference Paper
This paper presents an overview of a proposed tall building design platform that has the aim of determining the optimal external shape and structural system for tall buildings subject to aerodynamic loads. The platform is intended to bridge the gap between the traditionally manual conceptual design stage and the more automated detailed design stage...
Article
This research proposes a new design for a cantilever-type piezoelectric energy harvester in which a free tip is excited by any rotary motion of mechanical devices. A coupled field finite element model for the harvester is constructed using ANSYS and verification study is performed. Design optimization on the shape of the harvester is done to maximi...
Article
Full-text available
The performance of surface damping treatments may vary once the surface is exposed to a wide range of temperatures, because the performance of viscoelastic damping material is highly dependent on operational temperature. In addition, experimental data for dynamic responses of viscoelastic material are inherently random, which makes it difficult to...
Article
Full-text available
This paper presents an advanced design concept for a piezoelectric energy harvesting (EH), referred to as multimodal EH skin. This EH design facilitates the use of multimodal vibration and enhances power harvesting efficiency. The multimodal EH skin is an extension of our previous work, EH skin, which was an innovative design paradigm for a piezoel...
Article
Full-text available
This paper presents a design and experimental verification methodology for energy harvesting (EH) skin, which opens up a practical and compact piezoelectric energy harvesting concept. In the past, EH research has primarily focused on the design improvement of a cantilever-type EH device. However, such EH devices require additional space for proof m...
Conference Paper
This paper presents a piezoelectric energy harvesting skin (EHS) design using topology optimization. EHS was motivated to embody a power-generating skin structure by attaching thin piezoelectric patches onto a vibrating skin for the purpose of self-sustainable health monitoring with wireless sensors. In this paper the hybrid cellular automata (HCA)...
Article
A spacer grid (SG), which supports nuclear fuel rods (FRs) laterally and vertically with a friction grip, is one of the most important structural components in a PWR fuel. The forms of the grid straps and spring form are known to be closely related with the SG crush strength and the integrity of FR support, respectively. In this study, a new SG for...
Conference Paper
This paper presents a new energy harvesting (EH) concept design, referred to as EH skin structure. A generic design and experimental verification methodology will be proposed to demonstrate the feasibility of the EH skin for practical applications. In the past, EH researches have primarily focused on designing a device-level energy harvester, such...
Article
A topology optimization methodology, named "smooth boundary topology optimization," is proposed to overcome the shortcomings of cell-based methods. Material boundary is represented by B-spline curves and their control points are considered as design variables. The design is improved by either creating a hole or moving control points. To determine w...
Article
Full-text available
This paper presents an innovative design platform of a piezoelectric energy harvester (EH), called a segment-type EH, and its application to a wireless sensor. Energy harvesting technology is motivated to minimize battery replacement cost for wireless sensors, which aims at developing self-powered sensors by utilizing ambient energy sources. Vibrat...
Conference Paper
This paper presents an innovative design platform of piezoelectric energy harvester (EH), named segment-type EH, and its application to a wireless sensor. Energy harvesting technology is motivated to minimize battery replacement cost for wireless sensors, which aims at developing self-powered sensors by utilizing ambient energy sources. Vibration e...
Article
Full-text available
The spacer grid assembly, an interconnected array of slotted grid straps embossed with dimples and springs, is one of the main structural components of a pressurized light-water reactor (PWR). It takes the role of supporting the nuclear fuel rods which experience a severe expansion and contraction caused by harsh operational conditions such as an e...
Conference Paper
This paper presents a thorough study on a piezoelectric bimorph energy harvester which experiences a random vibration. Two different conceptual designs are considered for comparison of their power generation efficiency. For this comparison study, it is essential to construct a valid computer model and several model parameters (e.g., piezoelectric m...
Article
A spacer grid assembly, which is an interconnected array of slotted grid straps welded at the intersections to form an egg crate structure, is one of the core structural components for the nuclear fuel assemblies of a Pressurized light Water Reactor (PWR). The commercial spacer grid assembly is spot-welded at the crossing points of the intersection...
Article
Most signals between chips or packages in an electric circuit board require certain delays in order to achieve good timing. An extension of the circuit line that is proportional to the designated time delay has been a usual practice due to cost effectiveness. However, the layout of the line becomes dense due to the small size of packages or circuit...
Article
The new topology optimization method known as smooth boundary topology optimization (SBTO) is enhanced to deal with natural frequencies as a design characteristic. SBTO combines boundary representation using computer graphics with a selection criterion which determines the usefulness of generating a hole. Topological changes such as hole generation...
Article
Korea Atomic Energy Research Institute (KAERI) is in the process of carrying out a Nuclear Hydrogen Development and Demonstration (NHDD) Program by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950°C A coaxial double-tube hot gas duct (HGD) is a key component connecting the reactor pressure ves...

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