Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

Self-Tapping Fasteners for Lightweight Designs

2014-04-01
2014-01-0785
Abstract As automotive technology rapidly provides advances in lighter weight designs and materials, the technology to fasten and join them must keep pace. This paper will explore two uniquely different fastening technologies that are being used to address some of today's demanding application challenges in plastics and thin steel and aluminum sheet. These are two areas of application that have historically provided few good options for designers, especially as they attempt to push the envelope with progressive, light weight designs. The first technology is self- tapping screws for plastics that, although not new, are now evolving to enable smaller bosses and shorter thread engagements, and incorporate light weight design options. Although dependent on the demands of the application, these screws can be produced in both steel and, now, lighter weight materials such as aluminum and plastic.
Technical Paper

Fastener Coating Change for Efficient Functional Performance in Automotive Application

2013-11-27
2013-01-2899
Fasteners performance on account of rust is not consistent and conductivity is a concern. A surface coat is applied on fasteners to provide corrosion protection, i.e., protection against rust. When a metal comes in contact with Oxygen present in the air, it gets corroded. So, an extra protective layer is required to prevent the contact of metal with air, hence preventing corrosion. However, surface coating peel-off is a persistent problem observed while assembly of fasteners, which leads to impetuous rusting of parts. So, repeated use of fasteners in service life becomes a matter of concern. At the same time, it is important to provide conductive surface coating to fasteners used in fuel filler area. When a human body comes in contact with fuel filler area, it is necessary to discharge the static electricity of humans, in order to avoid explosion, due to generation of spark in presence of fuel fumes.
Technical Paper

Use of Single Point Interface Measures for Characterization of Attachments

2005-05-16
2005-01-2388
Often components or subsystems are attached to other systems through multiple fasteners at multiple locations. Examples may include things like compressors, alternators, engine cradles, powertrain mounting systems, suspension systems, body structures or almost any other interface between components or subsystems. Often during early design stages, alternative component or subsystem configurations are being considered that can have very different interface characteristics, such as alternators with different number of mounting fasteners, or suspension systems with different number of body structure interface attachments. Given these different mounting configurations, it can be difficult to meaningfully compare the interface performance of the two components or subsystems.
Technical Paper

Surface Mineralization as an Alternative to Cadmium Plating and Hexavalent Chromate Treatment for Corrosion Protection

2005-11-01
2005-01-3506
The purpose of this paper is to examine the use of a surface mineralization process for general corrosion protection. More specifically, this paper describes the use of surface mineralization (SM) as a non-hazardous and environmentally benign alternative to cadmium plating and hexavalent chromate treatment for protecting fasteners from corrosion in off highway applications. An engineered surface is founded on a mineral-based product that forms a thin metal silicate surface fully involving the substrate metal. Completed laboratory cyclic testing of SM treated fasteners compared with cadmium plated and hexavalent-chromate treated fasteners to 180 cycles using the GM 9540P protocol have demonstrated a significant increase in corrosion resistance of components protected by the SM process.
Technical Paper

Effect of Number of Measurement Locations in the Implementation of Iterative Wavenumber Fitting for Viscoelastically Damped Structures

2005-05-16
2005-01-2272
The work presented here is an experimentally-based parametric study of a layered viscoelastically-damped system containing intermediate structural fasteners. The effect of fastener preload, fastener location and the number of fasteners on the loss factor are examined. The loss factor is found to change by as much as 22% with change in some of these parameters. Two different approaches are used to measure loss factor. The first method uses the internal algorithm from a signal analyzer. The second method is an iterative algorithm that estimates the complex wavenumber, which is then used to find the damping loss factor. An advantage of the latter technique is the ability to measure loss factor over a range of frequencies. This research also investigates the effect of the number of measurement positions on the accuracy of loss factor. It is shown that the accuracy has a strong dependence on the number of measurement locations, particularly at low frequencies.
Technical Paper

Self-Loosening of Three Similar Bolted Joint Designs Using Finite Element Analysis

2014-04-28
2014-28-0035
Abstract Self-loosening of bolted connections is a crucial failure mode for joints under transverse dynamic load. For some years, three dimensional finite element analysis has been enabled for avoiding experimental investigations of self-loosening. The aim of this paper is to emphasize the effect of joint design on the self-loosening of bolted connections, which is important for product development in early design stage. Joints consisting of internally threaded nut components are often heavier and stiffer as compared with light weight designs consisting of a separate nut. The difference of self-loosening is significant between arrangements with nut thread component and separate nut, although the design versions only contain slight modifications. Hence it is necessary to evaluate the effect of light weight design on self-loosening.
Technical Paper

“U” Bolt Torque Influence over Leaf Springs

2014-05-07
2014-36-0024
Abstract ”U” bolts are fixing elements and they are used to clamp an elastic joint. From the past, they still looking as an old design and unfortunately, suspension engineers are not specialists in fasteners and elastic joints. That is why we will show important assumptions and concepts to design and specifications this clamp element “U” bolt and its influence over leaf-springs. Currently, “U” bolt is used to clamp an elastic or elastic-plastic joint of heavy duty suspension, formed by leaf-spring, axle, spring pad, “U” bolt plate. This kind of suspension is typically used to trucks, buses and trailers. We are wondering, which one important assumption that an engineer must be careful when designs a new suspension changing from old designs to an updated technology. We provide a theoretical analysis and a FEA analysis to compare torque efficacy x leaf-spring reactions and what are effects this relationship can cause in a suspension.
Technical Paper

Automated Fastening of Aircraft Cargo Door Structures with a Standard Articulating Robot System

2009-11-10
2009-01-3157
The demand of flexible and cost-efficient solutions for automated fastening systems inspired us to develop the robot and end-effector technology to fulfil the customer's requirement for a highly accurate, automated robot based drill and fastening system for an aerospace application. This paper describes an innovative robot cell for drilling and solid riveting installation in cargo door structures of a single aisle aircraft at EUROCOPTER in Germany. The required absolute positioning accuracy is reached by using a special compensation package for the robot that was developed by BROETJE-Automation. Our customer's application required a completely new type of end-effector; installing solid rivets and capable of operating within the inner structure of the cargo doors. This solution demonstrates how standard robots equipped with a mature compensation method by BROETJE-Automation resulted in a highly flexible and cost-efficient light weight automation response.
Technical Paper

The Underappreciated Fastener

2009-11-10
2009-01-3185
Don't underestimate the power of something as simple as the rivet for a repair to resolve a discrepant condition. Hole drilling discrepancies can occur daily on time sensitive parts which can cause scrapped parts, delays, extra expenses and angry customers. A key fastener for a repair on a multitude of discrepant conditions is the simple, malleable and low cost rivet to quickly and creatively repair a discrepant condition. Examples of deep, gouged or oblong countersinks at single or double flush fastener locations are just some of the conditions where a rivet repair can serve as the answer to the questions in a day's work.
Technical Paper

New Blind, Doweling, Temporary Fastener Design and Testing

2009-11-10
2009-01-3184
Several new families of expanding mandrel type of temporary (slave) fastener are in production and/or undergoing qualification tests. These fasteners are characterized by a collapsible mandrel that expands when needed over a center spindle. These fasteners are blind (installed and removed from one side only), and they provide locating (dowel) capabilities. This paper illustrates how these new fasteners work and how they are designed. Results of some testing of nominal ¼″, flush head fasteners in carbon-fiber reinforced plastic are shown. Design criteria include the temporary fasteners clamping ability, acceptable contact stresses, cyclic fatigue life, and strength.
Technical Paper

G12 Automatic Fastening Launch Vehicle

2014-09-16
2014-01-2263
Abstract The following is a unique case study expounding on automatic fastening technology designed and engineered to ramp up a Tier 2 supplier that had no experience with automatic fastening, to efficiently produce a large volume of fuselage panel assemblies with demanding process requirements in a very short amount of time. The automation technology integrated for the skin to stringer & skin to window frame fastening were two GEMCOR G12 five-axis CNC All-Electric fastening systems coupled with a Cenit offline part programming system. This joint solution served as a launch vehicle for Center Industries to efficiently supply the full rate of fuselage panel assemblies for a large volume commercial aircraft program without having any automatic riveting experience.
Journal Article

Numerical Investigation of the Rivet Installation in an Adhesively Bonded Joint and the Load Transfer in a Bolted/Bonded Hybrid Joint

2014-09-16
2014-01-2242
Hybrid (bolted/bonded) joining is becoming one of the innovative joining processes for light weight structures in the transport industry, especially in the aerospace industry where weight reduction and high joining requirements are permanent challenges. Combining the adhesive bonding with the mechanical joining -riveting for instance- can lead to an enhancement of the properties of the joint compared to the wide established riveting, as a result of a synergistic load bearing interaction between the fastener and the adhesive bondline. The influence of the rivet installation process on a hybrid joint regarding the joint stress state, the change of the bondline thickness as well as its effects on the joint performance and load transfer are some of the factors that drive the users to a better understanding of the hybrid joining process.
Technical Paper

A Lightweighting Solution for Converting an Aluminum Bracket to Plastic Using Long Fiber Thermoplastic Technology

2014-04-28
2014-28-0010
Abstract This breakthrough development involves material conversion from aluminum die cast to polypropylene long fiber thermoplastic (40% long glass filled) for a two wheeler bracket of a leading automotive OEM. The plastic bracket was developed working in collaboration with the molder, glass supplier, technology collaborator and the OEM. The new part needed to be designed lighter in weight, easier to process and suitable for painting, outdoor exposure and stringent dynamic conditions. The scope of this study includes the evaluation of the new material from different viewpoints and comparison of the same with the existing material. The submission will go through the intricate analyses carried out in the development process and highlight the key advantages over aluminum. Studies will include static and dynamic analysis, fiber orientation studies, gate location studies, etc.
Technical Paper

Innovation on Central Wheel Nut to Racing Prototype Vehicle

2013-10-07
2013-36-0472
The main characteristics required when fastening racing cars wheel are the resistance to self-loosening plus high-speed to assembling and disassembling of the wheel. To attend these two contradictory characteristics, it is necessary to develop differentiated fastening solutions. This work presents a new concept of fastening central wheel nuts for racing cars with improved fastening efficiency regard safety and assembly speed in comparison to the current fastening. The new wheel nut was designed and validated through analytical and FEM analysis as well as real tests.
Journal Article

Rivet and Bolt Injector with Bomb Bay Ejection Doors

2013-09-17
2013-01-2151
Electroimpact's newest riveting machine features a track-style injector with Bomb Bay Ejection Doors. The Bomb Bay Ejection Doors are a robust way to eject fasteners from track style injector. Track style injectors are commonly used by Electroimpact and others in the industry. Using the Bomb Bay Doors for fastener ejection consists of opening the tracks allowing very solid clearing of an injector when ejecting a fastener translating to a more reliable fastener delivery system. Examples of when fastener ejection is needed are when a fastener is sent backwards, when there are two in the tube, or when a machine operator stops or resets the machine during a fastening cycle. This method allows fasteners to be cleared in nearly every situation when ejecting a fastener is required. Additional feature of Electroimpact's new injection system is integrated anvil tool change.
Technical Paper

Theoretical and Practical Studies for Designing the Effective Length of Threaded Fasteners, Considering the Applied Torque on the Joint

2010-10-06
2010-36-0472
The effective length of screwed fasteners, regarding its correlation between safety assembling and production issues, has always been an open question for designers of fastening system. This work presents a real case of dimensioning one wheel nut according to theoretical and practical tests in order to guarantee a safe assembling. The objective of this study is to validate the geometric dimensioning of metric threads and their applications under real conditions.
Technical Paper

MPAC (Multi Panel Assembly Cell)

2009-11-10
2009-01-3091
Ever increasing process applications inspire us, as a supplier of aircraft, structural-assembly, and equipment, to design innovative and modular, manufacturing cells in compliance with modern specification. The result is the new highly flexible Multi Panel Assembly Cell (MPAC). This technical paper describes how benchmarks for flexible automated drilling and fastening are being achieved with the MPAC.
Journal Article

Improved Accuracy of Unguided Articulated Robots

2009-11-10
2009-01-3108
The effectiveness of serial link articulated robots in aerospace drilling and fastening is largely limited by positional accuracy. Unguided production robotic systems are practically limited to +/-0.5mm, whereas the majority of aerospace applications call for tolerances in the +/-0.25mm range. The precision with which holes are placed on an aircraft structure is affected by two main criteria; the volumetric accuracy of the positioner, and how the system is affected when an external load is applied. Production use and testing of off-the-shelf robots has highlighted the major contributor to reduced stiffness and accuracy as being error ahead of the joint position feedback such as backlash and belt stretch. These factors affect the omni-directional repeatability, thus limiting accuracy, and also contribute to deflection of the tool point when process forces are applied.
Technical Paper

Smart Lockwire: A Shape Memory Alloy Lockwire for Improved Reliability in Bolted Fixing in Automotive and Aeronautical Applications

2012-10-02
2012-36-0244
Shape memory alloys (SMA) have a unique behavior due to a reversible phase transformation between two solid crystalline structures: martensite (low temperature and low stiffness phase) and austenite (high temperature and a higher stiffness phase). This transformation can occur either as a result of temperature change or mechanical stress load, both above characteristic critical values of these materials. Due to the reversible nature of this phenomenon, direct transformation occurs when austenite transforms into martensite and reverse transformation when martensite transforms into austenite. The latter is induced by raising the temperature and it is this process that occurs during the generation of significant associated forces through the undergone deformation recovering of the material, being of fundamental importance for the use as actuators.
Technical Paper

A Prevailing Torque Nut with Incorporated Washer: A Solution for Rear and Front Axle Fastening

2012-10-02
2012-36-0288
Wheel hubs typically are set in vehicles through nuts with self-locking feature to assure safety. That feature may be done by an external component like a cotter pin, a deformable element incorporated to the nut like polyamide or metallic insert or some controlled mechanical deformation applied right on nut body. Nuts with some self-locking elements are being used in order to eliminate cotter pins from the system. However, during the maintenance of vehicles, some disadvantages appear like damage in thread axle due disassembling, considering controlled mechanical deformation nuts or the replacement of nut with polyamide insert to assure self-lock featuring. This paper presents a solution to replace a fastening in a current front and rear wheel-hub for a passenger vehicle. The study is made comparing a current solution, a controlled mechanical deformed nut - stover type - from a polyamide insert nut and an innovative prevailing torque nut with incorporated washer.
X