Browse Topic: Bolts

Items (2,369)
ABSTRACT In this paper a new bolt attachment method was explored, where the attaching bolts were divided into two sets. The first set of bolts was tightened and was used to connect the underbody plate to the hull under ordinary operations. The second set of bolts connecting the plate and the hull were not tightened and had some extra axial freedom. Under blast loading, the first set of bolts would break due to high tensile and shear loads, but the second set of bolts would survive due to extra axial freedom which allows the plate and the hull vibrate and separate from each other to a certain extent. A simulation model was developed to verify this concept. Three underbody plate-hull connection approaches were simulated and analyzed: 1) all tightened bolts, 2) some bolts not fully seated, 3) all bolts not fully seated. The simulation results show that with option 1), 100% of the bolts broke under the blast loading. With option 2) the not fully seated bolts survived and continued to
Kang., JianLiedke, MarkMason, James
ABSTRACT Protection Engineering Consultants (PEC) has performed static and dynamic-pendulum tests on bolted and welded connection sub-assemblies to generate data for development and validation of modeling approaches capable of accurately predicting the behavior of connections exposed to shock loads. The connections consisted of Rolled Homogeneous Armor (RHA) steel plates, Grade 8 bolts, and fillet welds of ER80-S wire, as typically used in armored vehicles. A summary of the forty physical tests on nine connection configurations are provided along with strain gage and Digital Image Correlation (DIC) data. The specimens were designed to have typical failure modes, i.e. bolt shear, plate tear-out, and weld shear fracture. Using these data, high-fidelity numerical models were developed, with exceptionally good comparisons to the experimental data. During the development of the numerical models, crucial modeling parameters were identified and were shown to have significant influence to the
Hadjioannou, MichalisBarsotti, MattSammarco, EricStevens, David
ARP6366 defines a comprehensive and widely-accepted set of specification guidelines to be considered by those seeking to use or design fiber optic sensors for aerospace applications. Some of the most common applications for fiber optic sensing within aerospace include inertial guidance and navigation (gyros) and structural monitoring (temperature, strain, and vibration sensing). Common sensor infrastructure elements include: transmitting and receiving opto-electronics (e.g., sources and receivers); multiplexing and demultiplexing optics; optical cabling; and signal processing (both hardware and firmware/software
AS-3 Fiber Optics and Applied Photonics Committee
This SAE Aerospace Standard (AS) establishes the geometric control requirements for bolts, screws, and studs where worded notes and symbolized notes are used for straightness, concentricity, squareness, and runout
E-25 General Standards for Aerospace and Propulsion Systems
Threaded joints are considered the most basic of components. Although in use for over a century, significant problems still exist with their usage. Wheel bolt loosening in overloaded segments such as HD tippers and high-speed intercity buses poses a safety challenge for drivers, passengers, and pedestrians. Wheel nut loosening is a notable cause of service, fretting, and cracks in the mating components; contributing a significant chunk of warranty cost to the company. The need of the hour is to reinforce these joints while keeping resources at bay. This paper establishes a methodology for the evaluation and design of a safe wheel bolt joint interface including key parameters such as embedding, axial forces, and shear forces. It is necessary to obtain the minimum preload requirement for a wheel bolt joint to hold the clamped surfaces intact, which if not maintained otherwise would cause relative movement, play, shear load onto the bolt, and eventually failure. For physically auditing
Raghatate, ShreyasSharma, SuchitSindal, Vinayak
Side doors are pivotal components of any vehicle, not only for their aesthetic and safety aspects but also due to their direct interaction with customers. Therefore, ensuring good structural performance of side doors is crucial, especially under various loading conditions during vehicle use. Among the vital performance criteria for door design, torsional stiffness plays an important role in ensuring an adequate life cycle of door. This paper focuses on investigating the impact of several door structural parameters on the torsional stiffness of side doors. These parameters include the positioning of the latch, the number of door side hinge mounting points on doors (single or double bolt), and the design of door inner panel with or without Tailor Welded Blank (TWB) construction. The findings of this study reveal that the change in latch position has the most significant influence on torsional stiffness, followed by the removal of TWB from the inner panel, upon implementation of suitable
Goyal, Vinay KumarSelvan, VeeraPandurangan, VenugopalUnadkat, SiddharthAlmeida, Neil Ricardo
The new idea discussed in this paper pertains to the carrier mechanism for spare wheels in heavy commercial vehicles. Typically, these vehicles are equipped with a spare wheel carrier featuring a rope mechanism for loading and unloading the spare wheel. The conventional placement of this system is on the side of the frame/chassis or within the limits of the side member. However, the tire-changing process in this system is often arduous, time-consuming, and requires significant effort. The proposed invention addresses these challenges by repositioning the spare wheel to a vertical orientation, facilitating easier access to its bolts and simplifying the removal process from the mountings. Furthermore, the innovation incorporates a three-way actuation system (Air Actuated, Electric motor-driven, or Hydraulic cylinder actuated mechanisms), thereby reducing the need for manual effort and enhancing driver comfort. The advantages of this invention over traditional carrier mechanisms include
Bonde, DevendraUpkare, Piyush PradipVerma, Rubal
Heavy vehicles such as construction machinery generally require a large traction force. For this reason, axle components are equipped with a final reduction gear to provide a structure that can generate a large traction force. Basic analysis of vertical load, horizontal load (traction force), centrifugal force, and torsional torque applied to the wheels of heavy vehicles such as construction machinery and industrial vehicles, as well as actual working load analysis during actual operations, were conducted and compiled into a load analysis diagram. The loosening tendency of wheel bolts and nuts that fasten the wheel under actual working load was measured, and the loosening analysis method was presented. The causes of wheel fall-off accidents in heavy trucks, which have recently become a problem, were examined. Wheel bolts are generally tightened by the calibrated wrench method using a torque wrench. The method is susceptible to variations in friction coefficient and tightening torque
Hareyama, SoichiManabe, Ken-ichiKobayashi, Satoshi
Mo-free 1.6-GPa bolt was developed for a Variable Compression Turbo (VC-Turbo) engine, which is environment friendly and improves fuel efficiency and output. Mo contributes to the improvement of delayed fracture resistance; therefore, the main objective is to achieve both high strength and delayed fracture resistance. Therefore, Si is added to the developed steel to achieve high strength and delayed fracture resistance. The delayed fracture tests were performed employing the Hc/He method. Hc is the limit of the diffusible hydrogen content without causing a delayed fracture under tightening, and He is the diffusible hydrogen content entering under a hydrogen-charging condition equivalent to the actual environment. The delayed fracture resistance is compared between the developed steel and the SCM440 utilized for 1.2-GPa class bolt as a representative of the current high-strength bolts. Owing to delayed fracture test, Hc/He of developed steel is 49.1 (Hc:3.39 ppm, He:0.069 ppm), and that
Sekine, DaikiOyanagi, MitsushiHamada, TakahiroFurukawa, TakayoshiMatsumoto, YosukeKanoe, Shinji
This procurement specification covers bolts and screws made from a corrosion and heat resistant, age hardenable, nickel base alloy of the type identified under the Unified Numbering System as UNS N07041 and of 155 ksi tensile strength at room temperature, with maximum test temperature of parts at 1400 °F
E-25 General Standards for Aerospace and Propulsion Systems
This information report presents recommendations on part number marking which provides for the maximum identification on bolts and nuts while ensuring adequate readability
E-25 General Standards for Aerospace and Propulsion Systems
This Aerospace Standard establishes the preferred diameter-pitch combinations of ISO metric 60° screw threads recommended for use in the aerospace industry for metric module bolts and nuts
E-25 General Standards for Aerospace and Propulsion Systems
Carbide-tipped gripper dowel secures the bolted joints and plays a significant role in the safety and reliability of the magnetic track brake system. With mainline trains speeds over 250 km/hr the magnetic track brake is automatically activated in case of the emergency brake. As the train passes over switches, crossings, and narrow curves with track distortion, it creates an exceptional lateral and longitudinal force on the bolted joints. The introduction of a gripper between several bolts reduces the shear force of the bolt to a large extent. This solution has the added benefit of facilitating maintenance. The paper presents the application of the gripper in the magnetic track brake and the validation of the gripper using analytical and experimental tests. This study may be applied to a wide range of bolted joints. The experimental results demonstrate the ability of gripper and maximize the durability of the bolt to prevent bolt joint failures. The results indicate a higher shear
K, ManjunathMishra, NirmalyaKumar, SandeepMontua, Sebastian
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