About

Mary Frecker is the Department Head of Mechanical Engineering at Penn State University and holds the Riess Chair of Engineering. She is a professor with affiliations in Mechanical Engineering, Biomedical Engineering, the Center for Acoustics and Vibration, and other related research centers. Her research areas include biomechanics and mechanobiology, design and manufacturing, and mechanical sciences, with particular interest in optimal design, compliant mechanisms, smart structures, and medical device design. Dr. Frecker has contributed extensively to the fields of compliant mechanisms, morphing structures, and bioinspired engineering, with a focus on innovative applications such as medical devices, aerospace structures, and adaptive systems. Her work involves the development of advanced modeling, optimization, and fabrication techniques to enhance the performance and functionality of complex mechanical systems.

Research topics

• Computer science
• Materials science
• Mechanical engineering
• Structural engineering
• Engineering

Selected publications

• A Systematic Design Approach for Magneto-Active Elastomers with Bayesian Network Classifiers Considering Manufacturing Variability

  Journal of Mechanical Design · 2026-01-09

  articleOpen accessSenior author

  Abstract Smart materials have demonstrated great potential for applications requiring flexibility, shape morphing, and reconfigurability. Among these, magneto-active elastomers (MAEs) are especially promising, achieving relatively large actuation deflections and forces under non-contact magnetic fields with rapid response times. Optimizing the structure and material properties of such advanced materials typically requires a systematic design strategy. Most approaches employ forward design methods, which are time intensive as they evaluate multiple design variables and the resultant performances to find optimal solutions. In this work, an inverse design strategy is proposed for MAE to efficiently identify the feasible design space that meets predefined performance requirements, such as actuated displacement, force thresholds, and actuation energy. Using a supervised Bayesian network classifier (BNC) adapted to training data and user-defined performance thresholds, this approach identifies a feasible design space capable of achieving customized performance goals. The BNC model is further enhanced by incorporating the manufacturing variability of additive manufacturing (AM) processes, specifically thickness variation. The design strategy is demonstrated with an MAE unimorph, using training data from an analytical model based on classic beam theory with free deflection and blocked force as performance metrics. The BNC mapping of the feasible design space demonstrates a resultant lower bending stiffness for displacement targets and a higher bending stiffness for the actuation force threshold. The feasible design space is further reduced to satisfy performance targets and manufacturing reliability. This approach serves as a powerful tool for identifying high performing designs that account for manufacturing variability for advanced material.

  PublisherOA PDFDOI

• Investigating Social Relevance and Knowledge Construction in Engineering Design Research Published in the <i>Journals of Mechanical Design</i> and <i>Mechanisms and Robotics</i>

  Journal of Mechanical Design · 2026-03-26

  article

  Abstract Engineering design research is evolving to incorporate socially relevant themes such as justice, ethics, and sustainability. With this evolution, new methods, theories, and concepts are introduced, resulting in a need for strategies aimed at gaining disciplinary depth and increased impact on other disciplines. This study examines how knowledge is constructed in engineering design research by analyzing articles published in well-respected venues for this field: the Journal of Mechanical Design (JMD) and the Journal of Mechanisms and Robotics (JMR). Using a systematic literature review, we analyze all JMD and JMR articles published in 2023 for discussion of social relevance, goal function (agentic/communal), and goal type (the type of knowledge construction it employs). Our findings show that research with communal goals, primarily “working with people” and “helping others,” tends to employ fortifying functions by refining and validating established methods. In contrast, agentic research is primarily focused on success in a particular role and relies on the advancing function by exploring the use of new theories, concepts, and methods in design contexts. This study critically examines how knowledge is constructed in engineering design research and provides a foundation for clarifying disciplinary identity and strengthening intellectual contributions. Because communal goals are associated with higher participation of women, these findings may inform strategies for improving diversity and inclusion in engineering design research.

  PublisherDOI

• Magneto-Active Compliant Slider-Rocker Mechanisms for Creating High-Energy Linear Motion

  Journal of Mechanisms and Robotics · 2026-04-27

  articleSenior author

  Abstract This study investigates the design of magneto-active bistable compliant mechanisms for creating high-energy motion. Compared to traditional actuation methods, magneto-active actuation can enable remote and wireless control due to the ability of uniform magnetic fields to remotely induce torque on magnetic materials. In this study, we focus on bistable compliant mechanisms with slider-rocker geometries, where the input is a magnetic field-induced torque and the output is the linear motion of the slider. We investigate how the bistable design enables triggerable energy release during the rapid snap-through motion after the mechanism passes the unstable equilibrium. First, we introduce methods to determine the magnetic programming direction of the input link that enables reversible actuation between stable positions at the lowest possible magnetic field strength. Next, we investigate the design space to identify the geometries that maximize the energy stored in the mechanism’s dominant spring and minimize the input magnetic field. Results from this study can guide the design of compliant mechanisms for creating high-energy motion when triggered by external uniform magnetic fields, such as remotely actuated rapid jumping or launching actuators for robotic applications.

  PublisherDOI

• Investigating woodpecker drumming using the center of percussion

  Bioinspiration & Biomimetics · 2026-03-09

  articleOpen access

  Woodpeckers are known for their distinctive drumming behavior used to forage for food and attract mates. During drumming, woodpeckers endure decelerations up to 1200 g without developing apparent brain injuries. Because of this extraordinary capability, woodpecker anatomy has served as an inspiration for structures that reduce forces during impacts, with potential applications in helmet design and vehicle safety. Previous studies theorized that impact energy from drumming is primarily absorbed by anatomical features in the woodpecker's head such as the tongue, hyoid bone, spongy bone, or lower beak. However, this explanation was challenged by a recent study reporting that shock-absorbing anatomy in the head would decrease drumming efficiency to an unrealistic threshold. In light of these conflicting theories, the exact methods used by woodpeckers to mitigate the adverse effects of drumming remain unclear. This work investigates the dynamics of woodpecker drumming using a principle called the center of percussion, which relates the location of an applied force (called the center of percussion, CoP) to a corresponding location of zero reaction force (called the center of rotation, CoR). We hypothesized that woodpecker anatomy exploits the relationship between the CoP and CoR to reduce reaction forces at critical anatomical locations, mitigating the adverse effects of drumming. We apply this hypothesis to woodpeckers by using two simplified rigid body models of the woodpecker's anatomy and performing parameter sweeps to investigate the location of zero reaction force when the applied force is at the woodpecker's beak. Results indicate zero reaction force in the lower body near the joint connecting the woodpecker's femur for a body-head model and zero reaction force near a joint in the lower neck for a neck-head model. The absence of reaction forces at these locations may provide critical insight into woodpecker dynamics and future investigation into strategies for reducing impact forces.

  PublisherDOI

• Pseudo-Reflection: A Graphical Method to Predict Stable Positions in Four-Bar and Five-Bar Bistable Linkages

  Journal of Mechanisms and Robotics · 2026-01-07

  article

  Abstract This work introduces Pseudo-Reflection, a graphical method for predicting candidate stable positions in bistable linkages and compliant mechanisms. Compared to computational methods that are typically used to model the energy landscape and determine stability, graphical methods can offer intuitive advantages, particularly in early-stage design. In particular, Pseudo-Reflection enables designers to rapidly visualize a linkage’s stable positions relative to a base geometry, making stable positions a controllable design input rather than a byproduct. This work shows how to use Pseudo-Reflection to predict the second stable position of bistable four-bar, slider–crank, and slider–rocker linkages with one dominant spring, and bistable five-bar linkages with two dominant springs. Each of these can be created as compliant mechanisms. Furthermore, this method integrates with existing graphical synthesis techniques and is compatible with modern computer-aided design tools, enabling designers to rapidly and intuitively predict stable positions.

  PublisherDOI

• Topology optimization of compliant mechanisms using augmented IFEMwith adaptive mesh refinement and level set method

  Structural and Multidisciplinary Optimization · 2025-07-01

  articleSenior author
  PublisherDOI

• Flexure-Based Locking Plates Can Modulate Interfragmentary Motion in Distal Femur and Diaphyseal Fractures: A Parametric Finite Element Analysis

  Journal of Biomechanical Engineering · 2025-11-15 · 1 citations

  articleOpen access

  Axial interfragmentary motion is known to stimulate fracture healing. A mechanically compliant fracture fixation plate incorporating flexures is proposed to provide controlled axial micromotion to long bone fractures. To explore the concept's feasibility, computational modeling of general diaphyseal and distal femur fractures treated with both rigid and compliant plates is conducted. In Part I of this study, a diaphyseal fracture finite element model for novel compliant plates is validated against experimental data with good agreement. In Part II, a parametric analysis is conducted using the validated model to characterize the performance of many compliant plate designs with varying geometry and materials. Under axial loading, all compliant plate configurations provided greater (1.03 mm versus 0.22 mm) and more symmetric (270-390%) axial interfragmentary motion than rigid plates. Steel compliant plates with thicker flexures (0.3-0.6 mm) may provide the best performance given their enhanced motion and comparable bending/torsional rigidity. In Part III, compliant plates are adapted for use in treating distal femur fractures. Results demonstrate that compared to a rigid plate, a compliant distal femur plate with increased thickness can effectively modulate interfragmentary motion-that is, increase the insufficient near cortex motion under low loads (from 0.14 mm to 0.23 mm) and reduce the excessive far cortex motion under large loads (from 7.96 mm to 2.54 mm). Flexure-based locking plates represent a promising new approach to treating diaphyseal and/or distal femur fractures. Additional research is needed to investigate in vivo performance.

  PublisherOA PDFDOI

• Frequency bandgap enhancement in locally resonant metasurfaces for <i>S</i>0 Lamb wave mode using topology-optimized resonators

  Journal of Applied Physics · 2025-01-28 · 3 citations

  articleOpen access

  Elastodynamic metasurfaces composed of surface-mounted resonators show great promise for guided wave control in diverse applications, e.g., seismic and vibration isolation, nondestructive evaluation, or surface acoustic wave devices. In this work, we revisit the well-studied problem of “rod-shaped” resonators coupled to a plate to reveal the relationship between the resonator's resonances and antiresonances obtained under unidirectional harmonic excitation, and the resultant frequency bandgap for S0 Lamb mode propagation once a metasurface is arranged. This relationship is shown to hold true even for non-prismatic resonators, such as those presented in our recent studies, in which we established a systematic resonator design methodology using topology optimization by matching a single resonator's antiresonance with a predefined target frequency. Our present study suggests that considering the waveguide (plate) during the resonator design is not essential and encourages a feasible resonator design approach to achieve wide bandgaps just by customizing a single resonator's resonances and antiresonances. We present a topology optimization design methodology for resonators that drive resonances away from antiresonances, i.e., a resonance gap enhancement, yielding a broadband S0 mode bandgap while ensuring the desired bandgap formation by matching antiresonances with a target frequency. The transmission loss of metasurfaces composed with topology-optimized resonators is numerically verified, confirming the generation of wider bandgaps compared to resonators designed without resonance gap enhancement and broadening the applicability of locally resonant metasurfaces.

  PublisherDOI

• Design optimization of flexible kerf structures under quasi-static loading

  2025-05-05

  articleSenior author

  Kerfing (relief cutting) is a technique that creates patterns of slender segments within planar surfaces. This study suggests using an optimization approach to determine the best kerf cell geometry within a surface of kerf cells (kerf panel). In finite element modeling, a beam element model is used, and the flexibility of these unit cells depends upon the material’s elastic modulus and the cell’s geometrical parameters. The distance between the cuts (<i>t_{of f}</i>), the width of each cut beam (<i>b</i>), and the cut density (<i>d_{ef f}</i>) were taken as the design variables of the optimization loop. In addition to the, cut shape (triangular, hexagonal, rectangular), the total number of unit kerf cells, cut thickness (<i>a</i>), and material properties are taken as inputs. The study uses a genetic algorithm, and the objective function is to minimize the coefficient of variation, which is a statistical measure that ensures that the stress distribution throughout the entire kerf structure is as uniform as possible. A nonlinear constraint enforces that the maximum von Mises stress acting on the kerf structure should not exceed a designer-specified limit. Case studies include optimizing kerf panels to uniformize stress distribution with different quasi-static loading conditions and minimum peak stresses induced. The results suggest that, although kerfing increases the flexibility in the structure, it reduces its load-carrying ability. However, the advantage of kerfing lies in its panels’ ability to propagate stress through deformation, resulting in lower maximum stress and more uniformly distributed stress compared to panels designed by intuition or experience.

  PublisherDOI

• A framework for analyzing goal alignment and social relevance of research papers to identify impact of women in design research communities

  Proceedings of the Design Society · 2025-08-01

  articleOpen access

  ABSTRACT: The underrepresentation of women and gender minorities in certain STEM fields remains a persistent issue, despite decades of research and outreach. Existing research has explored this disparity through lenses such as barriers to participation, whether there are differences in ability or competence, and the misalignment of individual goals with the affordances of STEM fields. This framework introduces a novel perspective by investigating how gender differences may influence the nature of research itself. We propose a coding protocol for systematically analyzing stated goal alignment through the lenses of social relevance, goal type (communal or agentic), and goal function (advancing or fortifying). The protocol was iteratively developed through a coding analysis of research papers from a major design engineering conference and journal (N = 297). The protocol is demonstrated through coding two papers, including one from the International Conference on Engineering Design. Use of this protocol will help researchers demonstrate how published research portrays social relevance and communal focus and thus improve understanding of the participation of women in STEM.

  PublisherOA PDFDOI

Recent grants

• EFRI-ODISSEI: Multi-field Responsive Origami Structures - Advancing the Emerging Frontier of Active Compliant Mechanisms

  NSF · $2.1M · 2012–2017

• NIH Grant R21EB006488

  NIH · $382k · 2010

• High-Strength High-Strain Structures Using Ceramic Cellular Contact-Aided Compliant Mechanisms (C3M)

  NSF · $629k · 2009–2013

• LEAP-HI/GOALI: DfAM of Smart Materials Using a Machine Learning Approach

  NSF · $500k · 2020–2023

Frequent coauthors

• Timothy W. Simpson

  Centraal Bureau voor de Statistiek

  35 shared

• George A. Lesieutre

  27 shared

• James E. Hubbard

  Edward Via College of Osteopathic Medicine

  26 shared

• Zoubeida Ounaies

  23 shared

• Aimy Wissa

  Princeton University

  18 shared

• Eric Mockensturm

  Pennsylvania State University

  17 shared

• James H. Adair

  Pennsylvania State University

  16 shared

• Saad Ahmed

  National University of Sciences and Technology

  15 shared

Labs

• Biomaterials and Biomechanics LabPI