Peter L Bishay

• PhD
• Professor (Full) at California State University, Northridge

Despite the tremendous advances in aircraft design that led to successful powered flights of aircraft as heavy as the Antonov An-225 Mriya, which weighs 640 tons, or as fast as the NASA-X-43A, which reached a record of Mach 9.6, many characteristics of bird flight have yet to be utilized in aircraft designs. These characteristics enable various spe...

Nowadays there are various prosthetic arm designs in the literature, the market, and CAD design websites, with different shapes, sizes, and degrees of freedom. Only limited options are available for controlling such prostheses. Prosthetic arm users reported muscle fatigue and unreliability when using the market-dominated myoelectric sensors. This w...

Featured Application Unmanned aerial vehicles (UAVs), radio-controlled (RC) drones. Abstract Birds have unique flight characteristics unrivaled by even the most advanced drones due in part to their lightweight morphable wings and tail. Advancements in 3D-printing, servomotors, and composite materials are enabling more innovative airplane designs i...

Conventional aircraft use discrete flight control surfaces to maneuver during flight. The gaps and discontinuities of these control surfaces generate drag, which degrades aerodynamic and power efficiencies. Morphing technology aims to replace conventional wings with advanced wings that can change their shape to control the aircraft with the minimum...

Shape memory alloy (SMA) wires are effective smart actuators since they provide relatively large actuation force and strain in a very limited space. Embedding SMA wires in flexible laminated composite plates or shells allows for creating active structures for morphing applications. However, the design of such structures is challenging due to the no...

The “Infinity” foot controller for controlling prosthetic arms has been improved in this paper in several ways, including a foot sleeve that enables barefoot use, an improved sensor-controller unit design, and a more intuitive control scheme that allows gradual control of finger actuation. Furthermore, the “Persistence Arm”, a novel transradial pro...

The applications of smart structures with integrated piezoelectric elements have been expanding in the last few decades due to the abilities of such structures to withstand mechanical loads and operate as sensors or actuators using their electromechanical coupling. The available manufacturing techniques can result in uncertainties in the structure'...

Although composite materials are used in many industries nowadays, an educational tool for the design of laminated composite structures is missing in the literature. This study discusses the most important features that should exist in such a tool and, hence, presents the “Composite Analysis and Design Apps” (CADA) tool. To improve engineering stud...

Composite materials are being used in many weight-sensitive applications due to their attractive features of high strength-to-weight and stiffness-to-weight ratios and design flexibility. In harsh dynamic environments, excitation frequencies can lead to resonance at some frequency bands, impacting the integrity and functionality of the whole compos...

Shape memory alloy (SMA) wires have been used to actuate prosthetic arms and robotic grippers, among other interesting applications. This work presents a compact system that amplifies the stroke of SMA wire actuators in a prosthesis’ forearm and locks them after actuation to save energy. The proposed system, called the “Clever Lever & Locking” (CLL...

Although the benefits of morphing wings have been proven in many studies in the last few decades, the wing skin design remains one of the challenges to advancing and implementing the morphing technology. This is due to the conflicting design requirements of high out-of-plane stiffness to withstand aerodynamic loads and low in-plane stiffness to all...

The dynamic behavior of solid structures is an important aspect that must be considered in the design phase to ensure that the designed structure will have desired response under external excitation. Periodic structures offer various design possibilities that can tailor the dynamic behavior of the structure to match the desired response under a giv...

The objective of this work is to characterize the nonlinear dependence of the piezoelectric d15 shear coefficient of a composite actuator on the static electric field and include this effect in finite element (FE) simulations. The Levenberg-Marquardt nonlinear least squares optimization algorithm implemented in MATLAB was applied to acquire the pie...

Morphing technology aims to improve both aerodynamic and power efficiency of aircrafts by eliminating traditional control surfaces and implementing uniform wings with seamless shapechanging ability. A lot of research has focused on proposing new designs for morphing wings, without implementation in a flying aircraft. Only few papers reported the de...

This paper highlights the amount of risk taken when a deterministic approach is used in designing composite structures without consideration of stochastic effects. The study treats all material and geometric parameters of the composite laminated plates under investigation as stochastic. Monte Carlo simulation is employed to investigate the stochast...

This paper presents a first concept of a new biomimetic transradial prosthetic arm design, called ‘MataPro-1,’ that features a 3D-printed hand bone structure that mimics the shape of human finger phalanges and palm bones, flexible elastic joints, artificial muscles, and silicone flesh that covers and protects the internal components, provides resto...

The finite element method (FEM) is one of the most important numerical methods used to solve various engineering problems in many physics' domains. In this study, engineering students enrolled in “Computer‐Aided Analysis and Design” course were first introduced to FEM through a simple computer code for analyzing two‐dimensional (2D) and 3D trusses....

This paper presents a new design for the core of a lightweight tail section of an unmanned aerial vehicle (UAV) with camber-morphing horizontal and vertical stabilizers. The core of each stabilizer is composed of an aluminum spar, two active end ribs, and multiple inactive ribs. Each active end rib is composed of a solid leading compartment connect...

Modeling the elastic behavior of solids in energy conversion and storage devices such as fuel cells and lithium-ion batteries is usually difficult because of the nonlinear characteristics and the coupled chemo-mechanical behavior of these solids. In this work, a perturbation finite element (FE) formulation is developed to analyze chemo-elastic boun...

This paper presents a new design for the core of a span-morphing unmanned aerial vehicle (UAV) wing that increases the spanwise length of the wing by fifty percent. The purpose of morphing the wingspan is to increase lift and fuel efficiency during extension, to increase maneuverability during contraction, and to add roll control capability through...

In this work, the finite element method (FEM) is used to characterize the effective thermo-electro-mechanical material properties of cement-based porous piezoelectric ceramic composites used in structural health monitoring (SHM) systems. The micromechanics representative volume element (RVE) approach is used with a realistic distribution of piezoel...

Since quantum-dot (QD) nanostructures in many applications are subjected to cyclic electrical and thermal loads, it is very important to analyze such nanostructures under transient thermal loads that affect the induced strains which in turn affects the response of the QD system. When the dimensions of the QDs are of the same order of magnitude as t...

Undergraduate research has a significant positive impact on the students’ educational experience but has many implementation challenges in curricular or co-curricular activities. This paper presents an approach for introducing undergraduate research to engineering students in a Numerical Analysis of Engineering Systems course, which is typically a...

This paper presents a new finite-element-based design procedure for geometrically periodic beam structures to target a specific desired attenuation frequency band. Using the “forward approach,” the effects of the cell geometric parameters on the location of the stop bands are first studied. Then using the “reverse approach,” explicit expressions fo...

Monte Carlo Simulations (MCS), commonly used for reliability analysis, require a large amount of data points to obtain acceptable accuracy, even if the Subset Simulation with Importance Sampling (SS/IS) methods are used. The Second Order Reliability Method (SORM) has proved to be an excellent rapid tool in the stochastic analysis of laminated compo...

Soft robotics is an emerging research field that uses deformable materials to build compliant and adaptable systems, using simple integrated mechanisms, enabling biomimetic behavior. This paper presents a sensitivity analysis of a shape memory alloy (SMA)-driven smart soft composite (SSC) bending actuator that is used as an artificial finger in rob...

The production methodology of alloyed quantum-dot (QD) structures introduced a new design degree of freedom for QD arrays which is the grading of the material composition in the QD growth direction. This enables QDs of same size to generate different colors when exposed to blue light based on the grading of each QD. The grading of the material comp...

A fully coupled thermo-electro-mechanical models of cylindrical and truncated conical GaN/AlN Functionally Graded Quantum Dot (FGQD) systems with and without WL are analyzed in this study to determine the effect of lattice mismatch strain grading on the electromechanical behavior of the FGQD system. This has a technological and fundamental importan...

In this paper, based on Von Kármán’s nonlinear theory and the classical lamination theory, a closed form expression is derived for the tangent stiffness matrix of a laminated composite beam element undergoing large deformation and rotation under mechanical and hygrothermal loads. Stretching, bending and torsion have been considered. A co-rotational...

Although micro-dilatation theory is very suitable and effective in modeling elastic porous materials, the absence of any guidance to evaluate or characterize its porosity-related parameters in the literature limited its use and applicability. This paper is proposing a methodology to characterize two of such important parameters, namely porosity cha...

The meshless local integral equation method is developed to analyze general two-dimensional boundary value problems in size-dependent magnetoelectroelastic solids. A consistent theory is developed for size dependent magnetoelectroelasticity. The strain gradients are considered in the constitutive equations for electric displacement and magnetic ind...

In this paper, a recently developed type of lower-order mixed finite elements is extended to model porous materials based on the microdilatation theory. These mixed finite elements are based on assuming independent linear generalized strain fields and collocating them with the generalized strains derived from primal variables (mechanical displaceme...

A meshless local Petrov-Galerkin (MLPG) model of porous elastic materials based on micro-dilatation theory by Cowin and Nunziato (1983) is developed. . This theory describes properties of homogeneous elastic materials with voids free of fluid. The primal fields (mechanical displacements, and change in matrix volume fraction which is also called mic...

In this article, a model for a multi-goal course project is reported and discussed. Teams of students are asked to create attractive Matlab Apps for topics related to “Fundamentals of Engineering” (FE) exam (hence called “FEApps”). The main goals of this project, discussed in details in the article, are: (1) allowing students practice coding in a n...

Influenced by the need for composites with stronger magneto-electric coupling, we present a novel numerical method called “Computational Piezo-Grains” (CPGs) for modeling different types of piezoelectric/piezomagnetic composites in the microscale. The advantage of this method is that the matrix and the inclusion of a grain can be modeled using only...

Influence of electric conductivity on intensity factors for cracks in conducting piezoelectric materials is investigated. Mechanical and electric loads are considered for 2D crack problems. The electric displacement in conducting piezoelectric materials is influenced by the electron density and it is coupled with the electric current. The coupled g...

Conceptually simple and computationally most efficient polygonal computational grains with voids/inclu-sions are proposed for the direct numerical simulation of the micromechanics of piezoelectric composite/porous materi-als with non-symmetrical arrangement of voids/inclusions. These are named "Multi-Physics Computational Grains" (MPCGs) because ea...

A simple and efficient method for modeling piezoelectric composite and porous materials to solve direct and inverse 2D problems is presented in this paper. The method is based on discretizing the problem domain into arbitrary polygonal-shaped regions that resemble the physical shapes of grains in piezoelectric polycrystalline materials, and utilizi...

A mechanics-based mathematical model for retinal detachment is developed, incorporating an energy-based criterion for propagation. Retinas with and without central tears are considered and contraction of the vitreous and extension of its fibrils, along with a pressure difference across the retina, are taken as the stimuli for detachment propagation...

In this paper, 2D and 3D Multiphysics Voronoi Cells (MVCs) are developed, for the Direct Mesoscale Numerical Simulation (DMNS) of the switching phenomena in ferroelectric polycrystalline materials. These arbitrarily shaped MVCs (arbitrary polygons in 2D, and arbitrary polyhedrons in 3D with each face being an arbitrary polygon) are developed, based...

A new class of hybrid/mixed finite elements, denoted “HMFEM-C”, has been developed for modeling magneto-electro-elastic (MEE) materials. These elements are based on assuming independent strain-fields, electric and magnetic fields, and collocating them with the strain-fields, electric and magnetic fields derived from the primal variables (mechanical disp...

Higher-order two-dimensional as well as low and higher-order threedimensional new Hybrid/Mixed (H/M) finite elements based on independently assumed displacement, and judiciously chosen strain fields, denoted by HMFEM-2, are developed here for applications in macro-mechanics. The idea of these new H/M finite elements is based on collocating the compone...

The Magnetorheological fluid, as one of the smart materials, is the focus of many researches running nowadays and is getting to replace many materials in several commercial applica-tions. This fluid is characterized by its ability to change from liquid into solid gel in few mil-liseconds as a result of applying a magnetic field. This paper deals wi...

The Magnetorheological fluid, as one of the smart materials, is the focus of many researches running nowadays and is getting to replace many materials in several engineering applications. This fluid is characterized by its ability to change from liquid into semi-solid gel in few milliseconds as a result of applying magnetic field. This paper deals...