Hill Engineering Blog

Hill Engineering announces agreement with VEQTER for Deep-Hole Drilling technology

Hill Engineering, answering strong demand for its residual stress measurement services, would like to announce our agreement with VEQTER, Ltd to license the Deep-Hole Drilling (DHD) technology. VEQTER, along with the University of Bristol, aided in the development of the DHD technique, and have practiced the technology for over 25 years. With this agreement, VEQTER will provide Hill Engineering with the equipment, technology, and support to deliver state-of-the-art DHD measurements within the North and South American Continents.

The Deep-Hole Drilling technique involves drilling a reference hole through the component and accurately measuring its diameter before and after residual stress release by trepanning coaxially around it. The measured deformation of the reference hole (before and after residual stress release) enables the original residual stresses to be calculated using elasticity theory.


Illustration of the deep-hole drilling measurement process (figure provided by VEQTER)

The Deep-Hole Drilling technique is used to measure bi-axial residual stresses acting in the plane at 90-degrees to the reference hole axis (i.e., σxx, σyy and σxy). Deep-Hole Drilling can be applied to a wide range of components and materials with measurement depths of up to 30 inches. DHD measurements can be performed within our testing laboratory or on-site.

Deep-Hole Drilling is an excellent complement to existing Hill Engineering residual stress measurement technology. The DHD technique provides the capability for bulk residual stress measurements through thick sections with minimal restrictions on material type and geometry.

In the early 1990’s, the University of Bristol revived and subsequently developed the Deep-Hole Drilling residual stress measurement technique under the supervision of Professor David Smith with substantial funding and support from the UK Nuclear Industry. By the early 2000’s the technique was providing accurate and robust results, helping to demonstrate nuclear plant compliance according to safety audit requirements. In 2004, VEQTER was founded (by Prof. David Smith and Dr. Ed Kingston) and started providing the commercial DHD measurement service for the engineering industry worldwide under an exclusive license agreement. Hill Engineering is pleased to bring VEQTER’s world-leading DHD technology to the North and South American Continents.  

Hill Engineering is a global leader in improving the performance of materials. We are a trusted partner to engineers seeking solutions in design, manufacturing, operations, and sustainment; delivering expertise in residual stress measurement, mechanical design, material testing, structural integrity, and service life extension. Please contact us today for more information about residual stress measurement or other services that we offer.