Dr. Christoph Schaal
California State University, Northridge
18111 Nordhoff St, Northridge, CA 91330
Phone: (818) 677-7980
Email: christoph.schaal@csun.edu
Dr. Christoph Schaal
California State University, Northridge
18111 Nordhoff St, Northridge, CA 91330
Phone: (818) 677-7980
Email: christoph.schaal@csun.edu
EDUCATION
University of Stuttgart, Germany
Thesis: Fuzzy Arithmetical Assessment of Health Monitoring for Multi-Wire Cables using Ultrasonic Waves
Committee: Profs. Lothar Gaul (University of Stuttgart, Germany), Michael Hanss (University of Stuttgart, Germany) and Claus-Peter Fritzen (University of Siegen, Germany)
Dipl.-Ing. (B.S. and M.S.) Engineering Cybernetics (Cybernetics and Systems Engineering) – Oct. 2009
University of Stuttgart, Germany
Thesis: Optimal State Estimation of Structural Vibrations with Piezoelectric Sensors (in German)
AWARDS AND FELLOWSHIPS
For the design, development and implementation of innovative laboratory experiments in the fields of ultrasonics, nondestructive testing, bioengineering and composites.
CECS Research Fellow California State University, Northridge 2018
Release time and funding for student salaries and supplies
Outstanding Engineering Achievement Merit Award The Engineers’ Council 2017
For outstanding contributions to the fields of theoretical and experimental mechanics employing ultrasonic technology, and the superb execution in instructional activities
Postdoctoral Fellowship German Academic Exchange Service (DAAD) 2014
Funding for a 12-month postdoctoral research project at the University of California, Los Angeles, CA
JSPS Summer Program Fellowship Japan Society for the Promotion of Science (JSPS) 2013
Funding for a two-month cooperative doctoral research project at the Tokyo Institute of Technology, Japan, and additional language and cultural courses
AREAS OF INTEREST
RESEARCH EXPERIENCE
Department of Mechanical Engineering, California State University, Northridge, CA
Ultrasonics and Applied Mechanics Laboratory (Director): conducting experimental, numerical and theoretical research on various ultrasound applications, such as nondestructive testing, medical devices, robotic systems, gyroscopes. Advising graduate students on their Master’s theses
Keck Composites Laboratory (Director): researching on cure monitoring and damage detection using embedded smart materials in composite structures, and investigating novel, sustainable materials for engineering applications. Supervising the operation of the equipment for the manufacturing and testing of composite structures. Implementing safety procedures, developing labs for related courses
Visiting Researcher Mechanical and Aerospace Engineering Jan. 2016 – present
University of California, Los Angeles, CA
Conducting analytical, numerical and experimental analyses on composite structures. Co-Mentoring Ph.D. students in Dr. Ajit Mal’s Nondestructive Evaluation Research Group
Postdoctoral Scholar Mechanical and Aerospace Engineering May 2014 – Dec. 2015
University of California, Los Angeles, CA
Nondestructive Testing: Analyzed wave propagation in anisotropic composite structures using realistic experimental methods and sophisticated finite element simulations. Developed nondestructive damage detection methods for mechanical and aerospace applications. Supervised undergraduate and graduate students in the laboratory (in collaboration with Dr. Ajit Mal)
System Dynamics: Developed a semi-analytical framework to predict energy loss of miniature high-performance angular rate sensors (in collaboration with Dr. Robert M’Closkey)
Research Associate Mechanical Engineering Nov. 2009 – Apr. 2014
Institute of Applied and Experimental Mechanics, University of Stuttgart, Stuttgart, Germany
Investigated linear and nonlinear wave propagation, coupling of waveguides and reliable structural health monitoring, considering uncertainty. Helped students to successfully complete research projects, and graded Bachelor’s and Master’s theses. Collaborated in a small team to write funding proposals and reports
Visiting Researcher Mechanical and Control Engineering Jun. 2013 – Aug. 2013
Fujita Lab, Tokyo Institute of Technology, Tokyo, Japan
Developed and applied an iterative learning controller for generating precise ultrasonic wave pulses to improve the reliability of wave-based structural health monitoring
GRANTS
HBCU/MI Equipment grant for establishing a “Multi-Scale Mechanical Characterization Laboratory”(No. 8092-RT-REP)
The Aerospace Corporation $15,500, Role: PI (CSUN) 2018 – 2020
Subreceipient of the grant “Strength and Damage Tolerance of Metal-Composite Hybrid Joints” in collaboration with University of California, Los Angeles (No. 0205-S-XD184)
Jet Propulsion Laboratory $35,000, Role: PI 2018 – 2018
Research Support Agreement on the “Study and modeling of Lamb wave propagation through pristine and flawed manufactured materials” (No. 1606860)
CSUPERB $15,000, Role: PI 2017 – 2019
New Investigator Grant on the “Treatment of pain along the spinal cord using focused ultrasound”
Internal (CSUN) Role: PI
Summer Grants Program awards ($3,000, 2019)
Research, Scholarship and Creative Activity awards ($5,000, 2017)
Summer Grants Program awards ($3,000, 2017)
Research, Scholarship and Creative Activity awards ($5,000, 2016)
TEACHING EXPERIENCE
Center for Educational Development of the Universities in Baden-W ̈urttemberg, Germany
Completed certification for academic teaching to improve learning experience and student success
Thesis: Teaching Engineering Mechanics I (in German)
Assistant Professor Jan. 2016 – present
Department of Mechanical Engineering, California State University, Northridge, CA
Undergraduate courses:
- Programming for Mechanical Engineers (ME 209)
- Numerical Analysis of Engineering Systems (ME 309)
- Machine Design (ME 330)
- Computer-Aided Design and Analysis and Lab (ME 386/L)
- Mechanics and Design of Composite Materials and Lab (ME 436/L)
Graduate courses:
Seminar in Engineering Analysis (ME 501B)
Mechanical Design with Composites (ME 536)
Lecturing, writing and grading homework, quizzes, exams and projects. Assisting students in computer-based labs as well as composites manufacturing and testing labs. Holding in-person and online office hours. Course coordinator for ME 386/L. Academic advisor to juniors and seniors. Advisor of composites club.
Lecturer Jan. 2015 – Dec. 2015
Mechanical and Aerospace Engineering Department, University of California, Los Angeles, CA
Undergraduate courses:
- Statics and Strength of Materials (MAE 101)
- Advanced Strength of Materials (MAE 156A)
- Mathematics of Engineering (MAE 182B)
Lectured, composed homework and exams, and instructed and supervised teaching assistants
Lecturer Nov. 2009 – Mar. 2014
Institute of Applied and Experimental Mechanics, University of Stuttgart, Stuttgart, Germany
- Engineering Mechanics (TM I–III, undergraduate)
- Smart Structures (SMARTS, graduate)
Developed and lectured a graduate Smart Structures course in English for German and international students. Lectured in-class exercises in Engineering Mechanics. Wrote and graded exams. Organized and held office hours. Guided teaching assistants in preparing in-class experiments
Teaching Assistant 2006, 2009
University of Stuttgart, Stuttgart, Germany
- Real-Time Data Processing (EZDV, graduate)
- Advanced Mathematics (HM I, undergraduate)
Assisted students in labs, and graded homework
OTHER PROFESSIONAL EXPERIENCE
German Academic Exchange Service (DAAD), New York, NY
System Administrator, Nov. 2009 – Apr. 2014
Institute of Applied and Experimental Mechanics, University of Stuttgart, Stuttgart, Germany
Trainee Functional Safety for Automotive Control Units, Nov. 2008 – Mar. 2009
ITK Engineering AG, Stuttgart, Germany
Software Engineer Statistical Cancer Viability, Apr. 2007 – Sep. 2008
Institute of Stochastics and Applications, University of Stuttgart, Stuttgart, Germany
MEMBERSHIP IN PROFESSIONAL ORGANIZATIONS
PUBLICATIONS AND PRESENTATIONS
Books
Articles in Books and Journals
[13] M. Brown, M. Safisamghabadi, D. Sanford, and C. Schaal. Shadowgraph visualization of the scattering of focused ultrasonic waves at bone-like constructs. Experimental Mechanics, 60:861–872, 2020. doi:10.1007/s11340-020-00609-1.
[12] D. Upadhyay and C. Schaal. Optimizing the driving trajectories for guided ultrasonic wave excitation using iterative learning control. Mechanical Systems and Signal Processing, 144:106876, 2020. ISSN0888-3270. doi: 10.1016/j.ymssp.2020.106876.
[11] C. Schaal, R. M’Closkey, and A. Mal. Semi-analytical modeling of anchor loss in plate-mounted resonators. Ultrasonics, 82:304–312, 2018. ISSN 0041-624X. doi: 10.1016/j.ultras.2017.09.009.
[10] C. Schaal and A. Mal. Core-skin disbond detection in a composite sandwich panel using guided ultrasonic waves. Journal of Nondestructive Evaluation, Diagnostics and Prognostics of Engineering Systems, 1(1):011006, 2018. doi: 10.1115/1.4037544.
[9] C. Schaal, S. Zhang, H. Samajder, and A. Mal. An analytical study of the scattering of ultra-sonic guided waves at a delamination-like discontinuity in a plate. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, pages 1–14, 2017 doi:10.1177/0954406217700176.
[8] C. Schaal and A. Mal. Lamb wave propagation in a plate with step discontinuities. Wave Motion, 66:177–189, 2016. doi: 10.1016/j.wavemoti.2016.06.012.
[7] C. Schaal, S. Bischoff, and L. Gaul. Damage detection in multi-wire cables using guided ultrasonic waves. Structural Health Monitoring, 15(3):279–288, 2016. doi: 10.1177/1475921716647249.
[6] C. Schaal, H. Samajder, Harsh Baid, and A. Mal. Rayleigh to Lamb wave conversion at a delamination-like crack. Journal of Sound and Vibration, 353(0):150–163, 2015. doi: 10.1016/j.jsv.2015.05.016.
[5] C. Schaal, S. Bischoff, and L. Gaul. Energy-Based Models for Guided Ultrasonic Wave Propagation in Multi-Wire Cables. International Journal of Solids and Structures, 64–65:22–29, 2015. doi:10.1016/j.ijsolstr.2015.03.010.
[4] H. Baid, C. Schaal, H. Samajder, and A. Mal. Dispersion of Lamb waves in a honeycomb composite sandwich panel. Ultrasonics, 56(0):409–416, 2015. doi: 10.1016/j.ultras.2014.09.007.
[3] S. Bischoff, C. Schaal, and L. Gaul. Efficient wave scattering analysis for damaged cylindrical waveg-uides. Journal of Sound and Vibration, 333(18):4203–4213, 2014. doi: 10.1016/j.jsv.2014.04.013.
[2] C. Schaal, S. Bischoff, and L. Gaul. Analysis of wave propagation in periodic 3D waveguides. Mechanical Systems and Signal Processing, 40(2):691–700, 2013. doi: 10.1016/j.ymssp.2013.06.021.
[1] L. Gaul, H. Sprenger, C. Schaal, and S. Bischoff. Structural health monitoring of cylindrical structures using guided ultrasonic waves. Acta Mechanica, 223:1669–1680, 2012. doi: 10.1007/s00707-012-0634-z.
Conference Papers
[34] C. Gonzales, A. Balyan, M. Mallari, and C. Schaal. Lamb wave-based nondestructive inspection using a mobile robotic platform. In P. Fromme and Z. Su, editors, Health Monitoring of Structural and Biological Systems XV, volume 11593, pages 562 – 571. International Society for Optics and Photonics, SPIE, 2021. doi: 10.1117/12.2583865.
[33] D. Upadhyay and C. Schaal. Iterative learning control for high-intensity focused ultrasound treatments. In P. Fromme and Z. Su, editors, Health Monitoring of Structural and Biological Systems XV,volume 11593, pages 260 – 270. International Society for Optics and Photonics, SPIE, 2021. doi:10.1117/12.2583539.
[32] D. Sanford and C. Schaal. High-intensity focused ultrasound scattering at mammal vertebrae. In Proceedings of the ASME International Mechanical Engineering Congress and Exposition – IMECE 2020, Virtual, 2020.
[31] S. Tai, F. Kotobuki, A. Mal, and C. Schaal. Numerical and experimental investigation of damage detection in stiffened composite panels using guided ultrasonic waves. In P. Fromme and Z. Su, editors, Health Monitoring of Structural and Biological Systems IX, volume 11381, pages 1 – 12. International Society for Optics and Photonics, SPIE, 2020. doi: 10.1117/12.2558845.
[30] L. Araque, L. Wang, S. Tai, A. Mal, and C. Schaal. Uncertainty characterization of guided ultrasonic wave properties in composite materials. In P. Fromme and Z. Su, editors, Health Monitoring of Structural and Biological Systems IX, volume 11381, pages 28 – 36. International Society for Optics and Photonics, SPIE, 2020. doi: 10.1117/12.2558853.
[29] A. Miranda, C. Gonzales, A. Balyan and C. Schaal. Mobile Robotic Platform for Inspecting Aircraft Surfaces Using Lamb Waves. In Proceedings of IWSHM – 12th International Workshop on Structural Health Monitoring, Palo Alto, CA, USA, 2019.
[28] S. Tai, L. Wang, L. Araque, A. Mal and C. Schaal. Effects of homogenization and quasi-isotropy assumptions on guided wave-based nondestructive testing methods. In Proceedings of IWSHM – 12th International Workshop on Structural Health Monitoring, Palo Alto, CA, USA, 2019.
[27] D. Upadhyay and C. Schaal. Ringing suppression for ultrasonic nondestructive testing using iterative learning control and H-infinity synthesis. In Proceedings of IWSHM – 12th International Workshop on Structural Health Monitoring, Palo Alto, CA, USA, 2019.
[26] L. Wang, L. Araque, S. Tai, A. Mal and C. Schaal. Feasibility analysis of various sensing methods for nondestructive testing of composites. In Proceedings of IWSHM – 12th International Workshop on Structural Health Monitoring, Palo Alto, CA, USA, 2019.
[25] M. Brown, D. Sanford, and C. Schaal. Imaging of the scattering of high-intensity focused ultrasonic waves at artificial bone replicas. In M. E. Grady, editor, Mechanics of Biological Systems and Materials & Micro-and Nanomechanics, Volume 4, pages 41–48, Cham, 2020. Springer International Publishing. ISBN 978-3-030-30013-5. doi: 10.1007/978-3-030-30013-5 8.
[24] C. Schaal, M. Brown, and K. Schulz. Experimental investigation of lamb wave-based edge detection methods. Proc. SPIE, 10972:1097223–1097223–11, 2019. doi: 10.1117/12.2515452. Christoph Schaal 6
[23] C. Schaal and V. Durgesh. Investigation of the scattering of focused ultrasonic waves at bones. In Proceedings of ASME International Mechanical Engineering Congress and Exposition – IMECE 2018, Pittsburgh, PA, USA, 2018.
[22] E. Hong and C. Schaal. Reverse engineering stiffened plates using guided wave-based nondestructive testing methods. Proc. SPIE, 10600:10600 – 10600–9, 2018. doi: 10.1117/12.2296745.
[21] M. Brown, M. Safisamghabadi, C. Schaal, and V. Durgesh. Visualization of the scattering of focused ultrasonic waves at solid-fluid interfaces. Proc. SPIE, 10600:10600–10600–10, 2018. doi:10.1117/12.2296744.
[20] C. Schaal, R. M’Closkey, and A. Mal. Parametric studies for semi-analytical investigation of plate-mounted resonators. Proc. SPIE, 10170:101700O–101700O–10, 2017. doi: 10.1117/12.2262002.
[19] C. Schaal, S. Tai, and A. Mal. On the assumption of transverse isotropy of a honeycomb sandwich panel for NDT applications. Proc. SPIE, 10170:1017022–1017022–8, 2017. doi: 10.1117/12.2260092.
[18] L. Maio, F. Ricci, V. Memmolo, N. D. Boffa, E. Monaco, A. K. Mal, and C. Schaal. Laser Doppler velocimetry and PZT sensing for the study of guided waves in a stepped aluminum plate. Proc. SPIE, 10170:101701S–101701S–15, 2017. doi: 10.1117/12.2260140.
[17] C. Schaal and A. Mal. Guided waves in a plate with a delamination-like discontinuity. In Proceedings of ASME International Mechanical Engineering Congress and Exposition – IMECE 2016, Phoenix, AZ, USA, 2016.
[16] C. Schaal, A. Mal and R. M’Closkey. Semi-analytical modeling of substrate loss of miniature resonators. In Proceedings of the 24th International Congress of Theoretical and Applied Mechanics – ICTAM 2016, Montreal, Canada, 2016.
[15] C. Schaal, A. Mal and R. M’Closkey. A semi-analytical method for calculating resonator energy loss into plate substrates. In Proceedings of the 3rd International Symposium on Inertial Sensors and Systems, Laguna Beach, CA, USA, 2016.
[14] C. Schaal, S. Zhang, H. Samajder and A. Mal. Analytical Investigation of the Interaction of Rayleigh and Lamb Waves at a Delamination-Like Discontinuity in a Thick Plate. In Proceedings of IWSHM – 10th International Workshop on Structural Health Monitoring, Palo Alto, CA, USA, 2015. doi:10.12783/SHM2015/225.
[13] C. Schaal, X. Cao and A. Mal. The Influence of Stiffeners on the Propagation of Guided Ultrasonic Waves. In Proceedings of IWSHM – 10th International Workshop on Structural Health Monitoring, Palo Alto, CA, USA, 2015. doi: 10.12783/SHM2015/248.
[12] L. Gaul, C. Schaal and S. Bischoff. Crack Detection in Overhead Transmission Lines by Ultrasonic Waves. In Proceedings of International Conference on Structural Engineering Dynamics – ICEDyn 2015, Lagos, Algarve, Portugal, 2015.
[11] C. Schaal and A. Mal. Dispersion of guided waves in composite laminates and sandwich panels. Proc. SPIE, 9438:94380L1–94380L–12, 2015. doi: 10.1117/12.2083870.
[10] C. Schaal and M. Hanss. Uncertainty Analysis for Crack Detection in Cylindrical Waveguides. PAMM,14(1):695–696, 2014. doi: 10.1002/pamm.201410330.
[9] C. Schaal and L. Gaul. Crack Detection in Multi-Wire Cables using Guided Ultrasonic Waves. In Proceedings of EWSHM – 7th European Workshop on Structural Health Monitoring, pages 2028–2035, Nantes, France, 2014.
[8] C. Schaal and M. Hanss. Uncertainty Analysis for Damaged Multi-Wire Cables. In Proceedings of the 11th International Conference on Structural Safety & Reliability, pages 1601–1607, New York, NY, USA, 2013.
[7] C. Schaal and M. Hanss. Fuzzy Arithmetical Assessment of Wave Propagation Models for Multi-Wire Christoph Schaal 7 Cables. In Randall Allemang, James De Clerck, C.er Niezrecki, and Alfred Wicks, editors, Special Topics in Structural Dynamics, Volume 6: Proceedings of the 31st IMAC, A Conference on Structural
Dynamics, 2013, Conference Proceedings of the Society for Experimental Mechanics Series, pages 177–185. Springer New York, 2013. ISBN 978-1-4614-6545-4. doi: 10.1007/978-1-4614-6546-1.
[6] C. Schaal, M. Krautter, and M. Hanss. Dispersion in Cylindrical Waveguides with Uncertain Parameters. PAMM, 12(1):537–538, 2012. doi: 10.1002/pamm.201210257.
[5] N. Higgins and C. Schaal. Inter-wire Coupling Model Development for Health Monitoring of Cable Structures. PAMM, 12(1):543–544, 2012. doi: 10.1002/pamm.201210260.
[4] C. Schaal and M. Hanss. Modeling wave propagation in coupled waveguides with uncertain parameters. In Proceedings of ISMA2012–USD2012, pages 4945–4958, Leuven, Belgium, 2012.
[3] C. Schaal and M. Hanss. Qualit ̈atsbewertung von Modellen mittels Unsicherheitsanalysen f ̈ur die wellengest ̈utzte Struktur ̈uberwachung. In Fortschritte der Akustik, pages 515–516, D ̈usseldorf, Germany, 2011. DEGA.
[2] S. Engelke, C. Schaal, and L. Gaul. Model Identification for a Modal State Estimator from Output-Only Data. In Tom Proulx, editor, Structural Dynamics, Volume 3: Proceedings of the 28th IMAC, A Conference on Structural Dynamics, 2010, Conference Proceedings of the Society for Experimental Mechanics Series, pages 1305–1312. Springer New York, 2011. ISBN 978-1-4419-9833-0. doi:10.1007/978-1-4419-9834-7.
[1] S. Engelke, C. Schaal, and L. Gaul. Beobachterentwurf zur Sch ̈atzung von Strukturschwingungen aufder Basis einer Output-Only Modalanalyse. In Schwingungsanalyse & Identifikation, volume 2093 of VDI-Berichte/VDI-Tagungsb ̈ande, pages 363–371. VDI Verlag GmbH, 2010. ISBN 978-3-18-092093-1.
Conference Presentations
[13] Investigation of the scattering of focused ultrasonic waves at bones. ASME’s International Mechanical Engineering Congress and Exposition – IMECE 2018, Pittsburgh, PA, USA, November 14, 2018.
[12] Parametric studies for semi-analytical investigation of plate-mounted resonators. SPIE Smart Structures/NDE conference: Health Monitoring of Structural and Biological Systems, Portland, OR, USA, March 27, 2017.
[11] On the assumption of transverse isotropy of a honeycomb sandwich panel for NDT applications. SPIE Smart Structures/NDE conference: Health Monitoring of Structural and Biological Systems, Portland, OR, USA, March 27, 2017.
[10] Guided waves in a plate with a delamination-like discontinuity. ASME’s International Mechanical Engineering Congress and Exposition – IMECE 2016, Phoenix, AZ, USA, November 2016.
[9] Analytical Investigation of the Interaction of Rayleigh and Lamb Waves at a Delamination-Like Discontinuity in a Thick Plate. 10th International Workshop on Structural Health Monitoring – IWSHM, Palo Alto, CA, USA, September 3, 2015.
[8] The Influence of Stiffeners on the Propagation of Guided Ultrasonic Waves. 10th International Work- shop on Structural Health Monitoring – IWSHM, Palo Alto, CA, USA, September 1, 2015.
[7] Dispersion of guided waves in composite laminates and sandwich panels. SPIE Smart Structures/NDE conference: Health Monitoring of Structural and Biological Systems IX, San Diego, CA, USA, March 10, 2015.
[6] Uncertainty Analysis for Crack Detection in Cylindrical Waveguides. 85th Annual Meeting of the Society of Applied Mathematics and Mechanics – GAMM, Erlangen-N ̈urnberg, Germany, March 13, 2014.
[5] Ultrasonic Monitoring of Overhead Power Lines and Stay Cables. Poster presentation at JSPS Summer Program 2013, Graduate University for Advanced Studies, Shonan Village, Japan, June 14, 2013.
[4] Fuzzy Arithmetical Assessment of Wave Propagation Models for Multi-Wire Cables. IMAC XXXI, Garden Grove, CA, USA, February 14, 2013.
[3] Modeling wave propagation in coupled waveguides with uncertain parameters. International Conference on Uncertainty in Structural Dynamics – USD/ISMA, Leuven, Belgium, September 18, 2012.
[2] Dispersion in Cylindrical Waveguides with Uncertain Parameters. 83rd Annual Meeting of the Society of Applied Mathematics and Mechanics – GAMM, Darmstadt, Germany, March 27, 2012.
[1] Model Quality Assessment for Wave-Based Structural Health Monitoring using Uncertainty Analysis (in German). 37th Annual Convention for Acoustics – DAGA, D ̈usseldorf, Germany, March 23, 2011.