Hill Engineering Blog

Residual Stress 101 vlog

by Robert Pires

Today, we’ve released the newest episode of our vlog: Residual Stress 101. The video is a return to basics, discussing the core of what it is we do here at Hill Engineering.

If you haven’t checked out our YouTube channel, it might be time. Our mission is to post content that helps highlight the capabilities of our organization, so that everyone can see how and why residual stress is important to their manufacturing processes.

Today’s post is a broad overview of what residual stress is, including the several techniques for measuring residual stress found in our lab. Look for future content that delves further into each technique, and contact us if you have any further questions or want to see a video related to something we haven’t discussed.  

BAMF version 7.0 release

by Josh Hodges

Following the inputs from our user community, we continue to develop new capability in the Broad Application for Modeling Failure (BAMF) software. We are happy to announce the new version of BAMF (7.0) is now available, which includes several significant enhancements that improve the usability of BAMF and adds to the state-of-the-art capability not available in other fatigue analysis tools. Continue reading BAMF version 7.0 release

Case Study: cold hole expansion process modeling

by Robert Pires

Cold hole expansion (Cx or cold expansion for short) of fastener holes is a technique that has been widely used in the aircraft industry to improve the fatigue performance of structural components. The cold hole expansion process introduces compressive residual stress near the vicinity of the hole that slows crack growth and can significantly improve fatigue performance. Continue reading Case Study: cold hole expansion process modeling

New publication – An Uncertainty Estimator for Slitting Method Residual Stress Measurements Including the Influence of Regularization

by Adrian DeWald

Hill Engineering recently published new research detailing our efforts to quantify uncertainty for slitting method residual stress measurements. This new approach provides a more accurate estimate of the measurement uncertainty associated with the slitting method, which is very helpful for probabilistic performance assessments. The paper is titled An Uncertainty Estimator for Slitting Method Residual Stress Measurements Including the Influence of Regularization and appears in Experimental Mechanics. The abstract text is available here along with a link to the publication. Continue reading New publication – An Uncertainty Estimator for Slitting Method Residual Stress Measurements Including the Influence of Regularization

Additive Manufacturing Benchmark Publication

by Adrian DeWald

Hill Engineering recently contributed to a publication related to residual stress measurement in additive manufacturing (AM) test specimens titled, Elastic Residual Strain and Stress Measurements and Corresponding Part Deflections of 3D Additive Manufacturing Builds of IN625 AM‑Bench Artifacts Using Neutron Diffraction, Synchrotron X‑Ray Diffraction, and Contour Method. The work was performed under the NIST AM-Bench program in collaboration with researchers from NIST, Los Alamos National Laboratory, University of California Davis, and Cornell High Energy Synchrotron Source. The abstract text is available here along with a link to the publication. Continue reading Additive Manufacturing Benchmark Publication

ASIP Conference 2019

by Adrian DeWald

Hill Engineering is presenting about residual stress aerospace forgings at the upcoming 2019 United States Air Force Structural Integrity Program Conference (ASIP) in San Antonio, TX. The 2019 ASIP Conference is specifically designed to bring together the world leaders in the area of aircraft structural integrity and to disseminate information on state-of-the-art technologies for aircraft structures in both the military and civilian fleets. Hill Engineering’s presentation will include a summary of recent work to quantify the residual stress variability in aerospace forgings. The abstract text is presented below. Continue reading ASIP Conference 2019

Welcome Dallen Andrew

by Adrian DeWald

We would like to welcome Dallen Andrew to Hill Engineering. Dallen has 10 years of experience as a mechanical engineer supporting aircraft structural integrity programs. He received a BS degree in Mechanical Engineering from Utah State University in 2009, and a MS degree in Mechanical Engineering from the University of Utah in 2011.

During his career, Dallen has gained experience in many aspects of aircraft structural integrity, with specialization in the fatigue and fracture of metals. He has worked on many projects requiring him to utilize his capabilities in  fatigue crack growth analysis, fracture mechanics, durability and damage tolerance analysis (DADTA), fatigue testing, continuing damage, residual stress, finite element analysis (FEA), and non-destructive inspection.

Dallen is an organizer of the Engineered Residual Stress Implementation (ERSI) working group developing the analytical framework to allow the benefits from deep engineered residual stresses to be applied to aircraft inspection intervals for the United States Air Force. Dallen has significant experience supporting the A-10 and T-38 aircraft fleets. He also has significant expertise in the use of AFGROW and NASGRO fracture mechanics and damage tolerance software packages.

Please contact us today for additional information about Hill Engineering and the services we offer.