Bolted Joints: Insights, Failures & Solutions

The use of Preload Requirement Charts in resolving bolting structural integrity issues - Bill Eccles, Bolt Science
One frequent root cause of bolted joint failures is insufficient preload. If the preload provided by the bolt is insufficient, joint separation and movement can occur resulting in possible bolt fatigue and self-loosening issues. In order that such problems do not occur it is vital that there is sufficient residual clamp force acting on the joint interface after accounting for the effects of the applied forces and embedding losses. A Preload Requirement Chart graphically illustrates this point as it looks at the forces acting on the joint interface. The presentation looks at this approach and includes some joint failure examples.

We are nuts about our bolts - Jarek Rosinski, Transmission Dynamics
Jarek will discuss fundamental basics of bolted joints design explaining how they work and highlighting common misconceptions. In a highly dynamic presentation the following topics will be included: rating of the bolts, typical and unusual failures of bolted joints, remedies and solutions, digital age instrumentation for remote monitoring of bolted joints. The presentation will include multiple case studies; lessons learned and lessons to be learnt!

The Nuts and Bolts of Non-Permanent Joints - Jamie Shenton - JCB
JCB extensively use bolted joints, but you may not realise just how varied that use is. This presentation will give an insight into some of JCB's bolted joints and the challenges encountered. Several obvious key joints will be highlighted but also some of the lesser known and forgotten joints. Jamie will discuss and share the critical role of bolted joints in machine production and the potential consequences of oversight. He will then explore how JCB achieves precision and efficiency in torque settings and ensuring proper joint configuration, something crucial in a high-volume production environment where confidence is key.

Bolted Joints in Electrical Connections – Thomas Llewellyn, Coexlion
Bolted joint design is critical for maintaining the correct performance of electrical connections in busbars, particularly in electric vehicles where high currents and dynamic loads are present.  Maintaining pre-load in these joints which typically have multiple interfaces and short grip lengths can be a challenge.  In this talk Thomas reviews best practices and some common misconceptions about robust design in busbar connections.

Exploring Bolt Technology in the Digital Age - John Doyle, MoreVision
Join John as he delves into the complexities and curiosities surrounding bolt reuse, challenging the concept of a "universal torque," and investigating the peculiar occurrence of certain bolts loosening while their apparent counterparts remain steadfast. This presentation will spotlight advanced bolt-tightening techniques and reliable secondary locking mechanisms, all illustrated through authentic case studies from the railway industry and practical bolt failure assessment tools. Furthermore, John will demonstrate how utilizing digital workflow forms enables workers to program intelligent torque wrenches, ensuring the implementation of superior bolt-tightening methods while simultaneously compiling tightening records. By storing this data in a cloud database, we provide a reliable assurance of bolt integrity.

Relaxation of Bolt Preload Resulting from Bolt Bending Arising from In-Plane Loads - Mike Welch, Michael A Welch (Consulting Engineers) Limited
Classical analysis methods have shown that flexural, in-plane, deflections due to shear strain in the flange pack of preloaded bolted joints produce bending moments and tensile loads on bolts within the joint. These tensile loads can be significant, particularly in joints made with long bolts, and are in addition to the bolt preload. These additional loads, combined with a high initial bolt preload, can cause yielding of the bolt, and result in relaxation of the initial preload. The presentation reviews this earlier work and presents a method of calculating the amount of preload relaxation.

The C1 Wedge Connection, a high-capacity, fast to install, cost-effective connection for wind turbines - Jasper Winkes, C1 Connections BV
Larger wind turbines, harsher conditions and floating foundations have pushed the traditional bolted L-flange connections past its limits. Following a rigorous testing program the C1 Wedge Connections has been developed to deliver the required higher capacities and allow faster and safer installation of offshore wind turbines. The technology has been tested over two years in a turbine and soon more connections will be installed.

PANEL DISCUSSION
This will provide an opportunity for attendees to engage with speakers, facilitating in-depth conversations about the day's topics and allow for the exploration of particular issues and potential solutions.

Bill Eccles, Bolt Science

Bill Eccles started his working life at Leyland Motors. He was Principal Engineer on bus chassis design before leaving to join Massey Ferguson Industrial as an Engineering Manager in the 1980’s and then to Ingersoll Rand as Design Manager. In 1992, Bill founded Bolt Science to allow him to focus on his interest in bolted joints. Subsequent consultancy work included work across many industries including involvement in accident investigation in which bolted joint failure was the root cause. He has developed software for the analysis of bolted joints that’s in use world-wide by several multi-national companies. His Doctorate is on the self-loosening of threaded fasteners and is a member of the British Standards fastener committee and a number of ISO fastener committees.
Read '60 Seconds with Bill Eccles'

Jamie Shenton, JCB

Jamie started at JCB as a graduate over 10 years ago. He quickly decided to focus his career on durability and fatigue. His experience ranges through structural simulation, physical testing & data collection, data analysis and process engineering. Jamie has been the technical lead of and participated in various grant funded research projects. In addition, he is an EIS committee member and sits on both the Durability and Fatigue Group and the Young Engineers Forum and continues to lead structural innovation and education within JCB and the wider EIS communities.
Read '60 Seconds with Jamie Shenton'

John Doyle, MoreVision

John Doyle graduate from London’s Imperial College and started work with Rolls Royce where he attained chartered status with the UK Institute of Mechanical Engineers. Having risen to the position of Chief Mechanical Engineer with Bombardier Transportation he started his own engineering consultancy in 1995 called MoreVision. It specialises in engineering analyses applied to railway vehicles, construction equipment, oil and gas plant, cranes and mechanical items for theme parks. His client list includes Shell, Bombardier, Siemens, Volvo and Disney. He won a UK Government SMART competition for software innovation and his www.ExcelCalcs.com website shares MS Excel based engineering calculations with its 80,000 members. The current focus of the business is www.ExcelWraps.com where further empowers Excel users by creating corporate cloud solutions for data, digital signatures & media. It has secured the support of Hitachi, Siemens and Wabtec in the UK rail industry and is set to deliver a quantum change to how engineers organise their workflows and engineering campaigns.
Read '60 Seconds with John Doyle'

Thomas Llewellyn, Coexlion

Thomas started his engineering journey as a placement year Student at Triumph Motorcycles over 20 years ago.  After a 15-year stint at Triumph in the chassis design department, his career took him to India.  Thomas held the position of chassis design head at Hero Motocorp, India’s highest volume motorcycle manufacturer, then moved to Ola Electric Mobility also in India, as senior director of mechanical engineering.  Ola were a billion dollar start-up, they are now India’s highest volume EV manufacturer.  In 2021 Thomas co-founded Coexlion.  Coexlion is an engineering consultancy, specialising in two-wheeler, L-Category vehicle design and EV powertrain design and simulation.  Coexlion has offices in Bangalore, India, and Leamington Spa in Warwickshire.  Alongside design consultancy, Coexlion works closely with BoltScience Limited, providing technical training on bolted joints in the UK and Asia.
Read '60 Seconds with Thomas Llewellyn'

Michael Welch - Michael A Welch (Consulting Engineers) Limited

Mike became a freelance consultant of engineering analysis, particularly stress analysis, in 1985. Previously he was Research and Design Manager at Gulick Dobson Special Products developing specialist/niche mining equipment. Before that he was a Senior Project Engineer at Babcock Power’s research center in Renfrew. He is now an Independent Researcher pursuing a number of interests in the field of classical stress analysis. He is particularly interested in preloaded bolted joints. The types of papers and technical notes that he is producing can be regarded as reviews of best practice and the presentation of original research and concepts.
Read '60 Seconds with Mike Welch'

Jasper Winkes - C1 Connections BV

Jasper Winkes studied mechanical engineering at the Eindhoven University of Technology in The Netherlands. Following his studies, he started Fistuca BV, developing innovative techniques for the foundation industry. In 2013 the development of a new pile driving technology for offshore monopiles, BLUE Piling Technology, started and in 2016 the development of the C1 Wedge Connection was initiated. Early 2019 the BLUE Piling Technology was acquired by IQIP BV and a new company was started for the C1 Wedge Connection, called C1 Connections.
Read '60 Seconds with Jasper Winkes'

Jarek Rosinski, Transmission Dynamics

After gaining his PhD degree at the Institute of Mechanics and Vibroacoustics in Krakow, Jarek joined the Design Unit, National Gear Technology Centre at Newcastle University where he spent 18 years of service. In 2006 Jarek left Newcastle University, to pursue wholly his company Transmission Dynamics (JR Dynamics Ltd), which he founded in 1996. Transmission Dynamics has grown organically, employing ca.  60 staff, including electronics, mechanical and software engineers and data analysts. Transmission Dynamics maintains the status of entirely privately owned company. He is a renowned consultant in the field of instrumentation, machine dynamics and power transmission systems, providing support for blue-chip companies around the globe.
Read '60 Seconds with Jarek Rosinski'