by Robert Pires
Maintaining the high quality of our work is our top priority. That’s why it’s important that our office environment promotes efficiency and qualitative communication here at Hill Engineering. From a project’s inception until its close, we strive to keep a workflow that handles our customer’s needs with consistent attention and care. Continue reading How We Work
by Adrian DeWald
As was previously discussed, Hill Engineering was recently awarded ISO17025:2005 accreditation for our Quality System. Developing a Quality System that is compliant with ISO is a significant effort, and at Hill Engineering we took it as an opportunity to improve the quality and documentation of our laboratory residual stress measurement services. Here’s a look back on some of the highlights in the development of our Quality System. Continue reading Building a Quality System
by Adrian DeWald
Fatigue is one important failure mode that guides the design and engineering of aircraft structure. As we have discussed previously aircraft are often manufactured using rivets and fasteners, which require drilling many holes in the structure during assembly. The holes act as stress concentrations, which tend to be locations where fatigue cracks are found. Compressive residual stresses act to hold cracks shut and result in improved fatigue performance. This residual compressive stress can provide substantial benefits in terms of performance, safety, cost, and inspection requirements. To take advantage of the benefits of compressive residual stress, cold expansion is often applied to aircraft fastener holes. Continue reading Cold expansion
by Adrian DeWald
Hill Engineering recently moved into a new facility in Rancho Cordova, CA. The new facility features a combination of laboratory, research and development, and office space; all of which are important as we work tenaciously to meet the needs of our current projects, while at the same time keeping an eye towards innovation and new opportunities. We have proudly named the primary conference room in our new facility the Prime Room, a fitting tribute to a special Hill Engineering collaborator, the inventor of the contour method, and inspirational figure, Mike Prime. Continue reading The Prime Room
by Camille Fowler
Aircraft undergo complex loading during their operation and lifecycle. For example, take off, landing, turbulence, and flight/ground maneuvers are all instances where significant loading occurs. The cyclic loading and unloading activates a failure mechanism called fatigue, which is most prevalent at the highest stressed regions. Continue reading Fracture surfaces evaluation
by Robert Pilarczyk
Fracture and fatigue are important material performance issues that Hill Engineering examines on a regular basis. Hill Engineering recently contributed to a publication titled “Investigating and interpreting failure analysis of high strength nuts made from nickel-base superalloy.” The publication includes a detailed review of work performed to understand the failure of these fracture critical nuts. The abstract text is copied below. A temporary link to download a pdf of the publication is provided at the bottom. Continue reading Failure analysis of high strength nuts
by Adrian DeWald
2016 was an exciting year at Hill Engineering. We accomplished so much and we wanted to take a moment to recognize some of the highlights. Continue reading 2016 Highlights at Hill Engineering
by Robert Pires
The Hill Engineering employees took a quick break from all the residual stress analysis to partake in a few fall-themed festivities this season. We recognize that enjoying quality time together is an important way to strengthen our resolve as a team. What better way to do that than through everybody’s favorite activities: pumpkin carving and food! Continue reading A Feast of Fall Festivities
by Adrian DeWald
We are excited to announce that Hill Engineering was recently awarded ISO17025:2005 accreditation!
ISO/IEC 17025 General requirements for the competence of testing and calibration laboratories is the primary ISO standard used by testing and calibration laboratories. Hill Engineering was accredited by the American Association for Laboratory Accreditation (A2LA). Compliance with the ISO/IEC 17025:2005 standard provides an internationally recognized basis for laboratory accreditation. The standard is used to govern Hill Engineering’s Quality System and entails adherence to rigorous technical requirements. Continue reading Hill Engineering achieves ISO 17025 certification
by Adrian DeWald
In a previous blog post we discussed, in general, issues related to residual stress in welding. In this post, we’ll follow up with a more detailed look at a specific welding application – linear friction welding of titanium alloys.
Titanium alloys are widely used in aerospace applications for their high strength to weight ratio, good corrosion resistance, and metallurgical stability. New joining methods are being implemented that allow for more efficient manufacture of titanium components. Linear friction welding (LFW) is a solid phase bonding process, which is particularly appropriate for titanium alloys. Due to the titanium’s great affinity for oxygen, nitrogen, and hydrogen, protective atmospheres must be used to prevent contamination of the welded material. LFW avoids the formation of a liquid phase during the welding process, and can therefore be carried out in air. Likewise, the typical defects caused by melting and solidification during traditional welding process such as pores, pinholes, shrinkage cracks and grain coarsening are avoided. However, as with all welding and deformation processes, understanding the weld residual stress is important. Continue reading Residual stress in linear frictions welds