About

Hamid Nayeb-Hashemi is a professor in the Department of Mechanical and Industrial Engineering at Northeastern University College of Engineering. He holds a PhD in Mechanical Engineering from MIT, earned in 1982, and has a background that includes a Master’s degree from MIT and both Bachelor’s and Master’s degrees from Tehran University in Iran. His research focuses on biomechanics and mechanics, with notable projects involving high-performance biodegradable composites from Qatari date palm waste, knee injury prevention and osteoarthritis risk in obesity, and the development of novel multi-functional composite sandwich panels. He has been recognized as a Fellow of the American Society of Mechanical Engineers and has contributed significantly to the field through research and publications. His work often involves biomechanics, structural protection, and the mechanical behavior of biological tissues, with a particular emphasis on orthopedic applications such as knee joint analysis and osteoarthritis prevention. Professor Nayeb-Hashemi has received multiple awards and grants for his research, and he is actively involved in advancing knowledge in biomechanics and mechanics.

Selected publications

• On the Electromechanical Instability of Polar Elastomers

  Journal of Engineering Materials and Technology · 2023-06-30

  article

  Abstract Based on a continuum theory that accounts for the underlying molecular physics of polar elastomers (PEs), a typical boundary value problem (BVP) is developed to analyze the electromechanical instability (EMI) of PEs with randomly distributed dielectric particles. Through extensive numerical simulations, the effects of various parameters such as particle volume fraction, particle size, and enhancement factor related to polar groups on the critical voltage leading to EMI of PEs are investigated. The results are presented in 3D phase diagrams, which may better help researchers to understand EMI of PEs and guide them in synthesis, design, and application of PEs in the fields of chemistry, physics, bio-engineering, etc.

  PublisherDOI

• Bending Stiffness Tunability of Biomimetic Scale Covered Surfaces Via Scales Orientations

  SSRN Electronic Journal · 2023-01-01 · 1 citations

  articleOpen accessSenior author
  PublisherDOI

• Bending stiffness tunability of biomimetic scale covered surfaces via scales orientations

  International Journal of Solids and Structures · 2023-06-30 · 3 citations

  articleSenior authorCorresponding
  PublisherDOI

• Predicting in-plane instability of high-speed rotating silicon multi-ring structures

  International Journal of Solids and Structures · 2023-07-08

  articleCorresponding
  PublisherDOI

• Predicting In-Plane Instability of High-Speed Rotating Silicon Multi-Ring Structures

  SSRN Electronic Journal · 2022-01-01

  articleOpen accessCorresponding
  PublisherDOI

• Dynamic Analysis of a Curved Beam With Tuning of Elastic Modulus and Mass Density in Circumferential Direction

  Journal of vibration and acoustics · 2022-05-27 · 1 citations

  articleSenior author

  Abstract Deformation and stress fields in a curved beam can be tailored by changing its mechanical properties such as the elastic modulus/mass density, which is typically done using functionally graded materials (FGM). Such functional gradation can be done, for instance, by using particles or fiber-reinforced materials with different volume fractions along the beam length. This article presents in-plane vibrations of functionally graded (FG) cantilevered curved beams. Both semi-analytical and finite element modeling are employed to find natural frequencies and mode shapes of such beams. The natural frequencies obtained from the analytical solution and finite element analysis are in close agreement with an error of 6.2% when the variance of material properties gradation is relatively small. In the analytical approach, the direct method is employed to derive the governing linear differential equations of motion. The natural frequencies and mode shapes are obtained using the Galerkin and the finite element methods. First, three natural frequencies and corresponding mode shapes are analyzed for different elastic modulus/mass density distribution functions. Furthermore, the natural frequencies of FG curved beams with a crack are also investigated. Our results indicate that larger cracks near the clamped side of the beam significantly decrease the first natural frequency. In the second and third vibration modes, cracks located in the area with a maximum moment result in the lowest natural frequency values. However, the second and third natural frequencies of the cracked curved beam are not affected by the presence of a crack, if the crack is located at the nodal points of the curved beam.

  PublisherDOI

• Stress analysis and thermoelastic instability of an annular functionally graded rotating disk

  Journal of Thermal Stresses · 2022-01-02 · 8 citations

  articleSenior authorCorresponding

  The in-plane behavior, linearized transverse vibration, and stability of a thin heated Functionally Graded (FG) rotating annular disk are investigated. The inner edge of the disk is clamped and heated to a constant temperature. The outer edge of the disk is free. A convective heat transfer is considered acting on the disk due to rotation in an environment with still air. The coefficient of thermal expansion, thermal conductivity, and Young's modulus vary radially according to the same power law. Assuming linear in-plane strains, the in-plane stresses are obtained and used to solve the linear equation of transverse motion to determine the critical speeds and stability characteristics. The results show that both the material property distribution and the heat convection coefficient have a significant effect on both the critical speed and stability characteristics. Moreover, heating a rotating FG disk can cause the modes with higher number of nodal diameters be excited before modes with lower ones. A convective coolant heat transfer acts as a strong stabilizer for the disk. Results suggests that an FG rotating disk with material properties increasing from the center is favorable to keep the disk stable and stress levels low if a continuous air supply is provided.

  PublisherDOI

• Design and Characterization of a Flexible Self-Inflating Mechanical Structure

  ASME Open Journal of Engineering · 2022-01-01 · 2 citations

  articleOpen accessSenior author

  Abstract Inflatable structures are commonly used in a variety of engineering applications such as robotics, space structures, medical devices, and automotive safety devices. However, inflation in these systems often requires a non-flexible external pressurized fluid source. Integration of the pressurized fluid source and the flexible construct sacrifices some of the main advantages of the soft structures such as overall flexibility of the system, weight, and cost of fabrication. In this paper, we introduce a novel design for self-inflating structure with embedded pressurizing module. The design is based on integrating a flexible dome with a cylinder. The pressure inside the cylinder is controlled by subjecting dome to a cyclic compression, causing air exchange between the dome and the cylinder. The performance of this design is fully validated through finite element simulations using fluid structure interactions as well as experimental investigations. The results show that a higher pressure is achieved by having smaller dome height. In addition to controlling internal pressure of the cylinder, the design can be used to control the stiffness of the flexible structure such as soft robotics through pressurization. An application of this conceptual device such as pressurizing a tire is presented. This device is integrated within a tire and tire rotation as well as load on the tire have been shown to pressurize the tire. The final pressure and time to achieve maximum pressure depend on the load to the axel of the tire and tire rotational speed, respectively.

  PublisherOA PDFDOI

• Energy Dissipation During Prey Capture Process in Spider Orb Webs

  Journal of Applied Mechanics · 2020-06-22 · 14 citations

  articleOpen accessSenior author

  Abstract Capture of a prey by spider orb webs is a dynamic process with energy dissipation. The dynamic response of spider orb webs under prey impact requires a multi-scale modeling by considering the material microstructures and the assembly of spider silks in the macro-scale. To better understand the prey capture process, this paper addresses a multi-scale approach to uncover the underlying energy dissipation mechanisms. Simulation results show that the microstructures of spider dragline silk play a significant role on energy absorption during prey capture. The alteration of the microstructures, material internal friction, and plastic deformation lead to energy dissipation, which is called material damping. In addition to the material damping in the micro-scale modeling, the energy dissipation due to drag force on the prey is also taken into consideration in the macro-scale modeling. The results indicate that aerodynamic drag, i.e., aero-damping, plays a significant role when the prey size is larger than a critical size.

  PublisherOA PDFDOI

• Bending behavior of biomimetic scale covered beam with tunable stiffness scales

  Scientific Reports · 2020-10-13 · 14 citations

  articleOpen access

  Biomimetic scales provide a convenient template to tailor the bending stiffness of the underlying slender substrate due to their mutual sliding after engagement. Scale stiffness can therefore directly impact the substrate behavior, opening a potential avenue for substrate stiffness tunability. Here, we have developed a biomimetic beam, which is covered by tunable stiffness scales. Scale tunability is achieved by specially designed plate like scales consisting of layers of low melting point alloy (LMPA) phase change materials fully enclosed inside a soft polymer. These composite scales can transition between stiff and soft states by straddling the temperatures across LMPA melting points thereby drastically altering stiffness. We experimentally analyze the bending behavior of biomimetic beams covered with tunable stiffness scales of two architectures-one with single enclosure of LMPA and one with two enclosures of different melting point LMPAs. These architectures provide a continuous stiffness change of the underlying substrate post engagement, controlled by the operating temperature. We characterize this response using three-point bending experiments at various temperature profiles. Our results demonstrate for the first time, the pronounced and reversible tunability in the bending behavior of biomimetic scale covered beam, which are strongly dependent on the scale material and architecture. Particularly, it is shown that the bending stiffness of the biomimetic scale covered beam can be actively and reversibly tuned by a factor of up to 7. The developed biomimetic beam has applications in soft robotic grippers, smart segmented armors, deployable structures and soft swimming robots.

  PublisherOA PDFDOI

Awards & honors

• Fellow, American Society of Mechanical Engineers