Hill Engineering Blog

BAMF webinar

Hill Engineering will be participating in an upcoming webinar related to 3D fatigue analysis using our Broad Application for Modeling Failure (BAMF) software. BAMF is a software tool for predicting the growth of fatigue cracks in 3D parts. Starting from an assumed initial flaw, BAMF combines stress and crack growth analyses to predict the evolution of crack shape and size in 3D. BAMF provides a robust and automated link between two leading tools: AFGROW and StressCheck™. Continue reading BAMF webinar

Residual stress biaxial mapping validation

Hill Engineering recently published new research detailing our efforts to validate the PSR biaxial mapping technique for residual stress measurement.

This new technique generates two-dimensional maps of additional residual stress components over the same plane as the original contour method measurement. The paper is titled Assessment of Primary Slice Release Residual Stress Mapping in a Range of Specimen Types and appears in the November 2018 volume of Experimental Mechanics. Continue reading Residual stress biaxial mapping validation

2019 SEM Annual Conference and Exposition on Experimental and Applied Mechanics

Hill Engineering will be presenting at the upcoming SEM Annual Conference and Exposition on Experimental and Applied Mechanics in Reno, NV from June 3rd through June 6th. We invite you to come see us. This conference focuses on all areas of research and applications pertaining to experimental mechanics, and has evolved to encompass the latest technologies supporting:

  • optical methods
  • additive & advanced manufacturing
  • dynamic behavior of materials
  • biological systems
  • micro-and nano mechanics
  • fatigue and fracture
  • composite and multifunctional materials
  • residual stress
  • inverse problem methodologies
  • thermomechanics
  • time dependent materials.

Hill Engineering’s presentation will include a summary of recent work related to regularization uncertainty in slitting residual stress measurement. The abstract text is presented below.

This presentation describes the development of an uncertainty estimate for slitting residual stress measurement. The uncertainty estimate includes a newly developed uncertainty estimate related to the smoothing used in the stress calculation procedure called the regularization uncertainty. This work describes the approach to define the regularization uncertainty, shows the usefulness of the uncertainty estimate in a numerical experiment and a repeatability study. The uncertainty estimate is shown to meet an acceptance criterion that compares the calculated (measured) stress ± its uncertainty estimate to the true value for the numerical experiment or the mean stress from the repeatability study. This works shows the regularization uncertainty estimate to be a necessary contributor to the uncertainty in slitting and additionally the uncertainty estimate developed here reasonably predicts the uncertainty present in slitting method residual stress measurements.

If you are planning to attend the conference please stop by to discuss Hill Engineering’s capabilities in fatigue analysis and design and residual stress measurement . Please contact us for more information.

Meet our new 3D scanner

We at Hill Engineering are always looking for ways to improve the accuracy and efficiency of our laboratory. That’s why we recently acquired a 3D scanner for our laboratory, which will aid in many aspects of our residual stress measurement processes, as well as enable us to provide further services to our customers. In the newest video on our YouTube channel , we discuss some of the highlights of this tool. Continue reading Meet our new 3D scanner

Residual stress in additive manufacturing

Additive manufacturing (AM) is a manufacturing process that deposits material in a controlled manner to build three-dimensional part geometry (bit by bit). This is in contrast to traditional manufacturing processes where material is cut or removed (i.e., subtracted) from the raw stock to create the intended part shape. The potential for additive manufacturing to significantly improve the economics and performance of manufactured parts for certain applications has made it a popular topic. However, since most additive manufacturing processes are highly thermal (e.g., material is deposited in a melted form and solidifies into the desired shape) significant residual stresses can develop. Hill Engineering has been working with many collaborators to better understand the influence of these processes on residual stress. Continue reading Residual stress in additive manufacturing

Residual Stress 101

The upcoming SEM Annual Conference and Exposition on Experimental and Applied Mechanics will include a Pre-conference Course titled: Residual Stress 101. Scheduled for Sunday, June 2, 2019 from 9:00 a.m. to 5:00 p.m, the residual stress short-course aims to cover a broad, practical introduction to residual stresses for interested students, researchers and industrialists. Michael Prime, Michael Hill, Adrian DeWald, Antonio Baldi, and Cev Noyan will teach the course. Registration is currently open through the SEM website. Continue reading Residual Stress 101

Propulsion Safety & Sustainment Conference 2019

Hill Engineering is presenting at the upcoming Propulsion Safety & Sustainment Conference (PS&S) in Washington, D.C. from April 23rd through April 25th. We invite you to come see us. The mission of this conference is to proactively address or prevent problems with safety, readiness, reliability, and sustainment within the tri-service turbine engine fleet. This is to be accomplished through the transition of existing and emerging technologies. Hill Engineering’s presentation will include a summary of recent work related to residual stress measurement in support of production quality control. The abstract text is presented below. <!–more–>  

Aircraft engine and structural components are being produced from forgings with increasingly complex geometries in a wide range of aerospace alloys. The forging process involves a number of steps required to attain favorable material properties (e.g., heat treatment, rapid quench, cold work stress relieving, and artificial aging). These processing steps, however, also result in the introduction of residual stress. Excessive bulk residual stresses can have negative consequences including: part distortion during machining and/or during service, reduced crack initiation life, increased crack growth rates, and an overall reduction in part life. This presentation will describe an approach for quality management of residual stresses in aerospace forgings. The quality management system relies upon computational process modeling, residual stress measurement, and the integration of these concepts within the framework of a standard production quality system.  

If you are planning to attend the conference, please stop by to discuss Hill Engineering’s capabilities in fatigue analysis and design and residual stress measurement. Please contact us for more information.  



Illustration of residual stress in an aluminum forging before and after cold work residual stress relief