Author: atdewald
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Legacy Post: Cold expansion (Feb 2017)
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…
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Legacy Post: The Prime Room (Feb 2017)
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…
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Legacy Post: Failure analysis of high strength nuts (Jan 2017)
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.…
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Legacy Post: 2016 highlights at Hill Engineering
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. Early in the year, we were in the middle of Hill Engineering’s largest ever facilities planning/construction project. We had just selected our new office location and needed to plan and…
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Legacy Post: Hill Engineering achieves ISO 17025 certification (Dec 2016)
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…
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Legacy Post: Residual stress in linear friction welds (Dec 2016)
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…
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Legacy Post: ASIP Conference 2016 (Nov 2016)
Hill Engineering is presenting about fatigue analysis methods for cold expanded aircraft fastener holes at the upcoming 2016 Aircraft Structural Integrity Program (ASIP) Conference in San Antonio, TX. Cold hole expansion is a method commonly used to induce compressive residual stress around the perimeter of fastener holes, which are common in aircraft structure. The compressive…
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Legacy Post: Residual stress analysis (Oct 2016)
Material fabrication processes like forging, rolling, extrusion, quenching, additive manufacturing, machining, and welding lock spatially varying residual stress fields into structural materials. These residual stresses can influence the way that materials perform (e.g., fatigue, fracture, distortion, and corrosion). Hill Engineering has developed expertise to support many different types of residual stress analysis, which we apply…
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Legacy Post: Residual stress in welding (Sep 2016)
Welding is a very common manufacturing process that is used to join materials together to form assemblies and systems. In many cases the welded joints are large, have reduced material properties (e.g., stress corrosion cracking resistance, fracture toughness), and contain defects. The welded joints tend to be critical locations in terms of design and sustainment.…
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Legacy Post: AFGROW User Workshop (Sep 2016)
Hill Engineering is presenting about fatigue analysis as part of the AFGROW User Workshop 2016 in Layton, UT. The objective of the workshop is to provide a forum for AFGROW users to exchange information and ideas related to fracture and fatigue. Hill Engineering’s presentation will include a summary of recent work on the formulation and…