Browse Topic: Bulkheads
Innovators at NASA Johnson Space Center have developed a method using low-viscosity RTV silicone to form durable seals between polymer bladder and metal bulkhead interfaces to be used for inflatable space habitats.
In large scale industries attempts are continuously being made to automate assembly processes to not only increase productivity but also alleviate non-ergonomic tasks. However this is not always technologically possible due to specific joining challenges and the high number of special-purpose parts. For the riveting process, for example, semi-automated approaches represent an alternative to optimizing aircraft assembly and to reduce the exposure of workers to non-ergonomic conditions entailed by performing repetitive tasks. In [1], a semi-automated solution is proposed for the riveting process of assembling the section barrel of the aft section to its pressure bulkhead. The method introduced a dynamic task sharing strategy between human and robot that implements interaction possibilities to establish a communication between a human and a robot in Human-Robot-collaboration fashion. Although intuitive, interacting with the robot constantly is still not natural for the worker as in the manual process no explicit communication between both workers is needed. In this work a communication-free Human-Robot-collaboration solution is presented. The method developed not only enables sharing assembly missions by dividing tasks based on skills, but also offers the possibility of decision making to the robot. In this context, off-the-shelf Artificial Intelligence planning tools are used to model the work-flow of the human as well as the task of the robot handling alongside possible uncertainties yielding while perceiving the environment or the activity of the human.
The methods for improving the torsion stiffness of a pickup chassis frame were discussed, including increasing the part thickness on frame, enlarging the cross section of rails, and adding bulkhead feature inside the rails. Sizing optimization was conducted to get the optimal thickness configuration for frame parts and meet the siffness requirement. The cross section of frame rails was parameterized and shape optimization was conduted to get the optimal rail cross sections for stiffness improvement. Additional bulkheads were added to the frame rails, and sizing optimization conducted to find the most effective bulkheads to add and their optimal gauge. A material efficiency ratio μ is used to evaluate the efficiency of a design change with respect to torsion stiffness. Among those torsion improvement methods, adding bulkhead feature gives the highest material efficiency ratio, but the stiffness improvement is very limited. Enlarging the rail sections and increasing the part thickness can improve the torsion to over 9% while the material efficiency ratio is relatively low. Simultaneous structural optimization was conducted combining above two and all torsion improvement methods to obtain the most efficient lightweighting design. For different design targets, the corresponding method combination was obtained through optimization. For torsion improvement within 3.2%, adding bulkhead feature is the most efficient design with high material efficiency ratio (μ > 7.936 kN-m/rad/kg). For improvement target 3.2%-5.4%, the design combining adding bulkheads and enlarging the rail sections is most efficient with μ in range of 3.861-7.936 kN-m/rad/kg. For improvement target 5.4%-10.3%, the design combining all three improvement methods gives the optimal performance, with material efficiency ratio μ in range of 2.333-3.861 kN-m/rad/kg. For target over 10.3%, above stiffness improvement methods do not offer an efficient solution and the frame needs to be redesigned. This study gives guideline on adopting the methods for stiffness improvement and achieving the optimal lightweigting design.
Ever increasing process applications inspire us, as suppliers of aircraft, structural-assembly, and equipment to design innovative and modular, manufacturing cells in compliance with modern specifications. The result is the new flexible C-Frame Panel Assembly Cell (CPAC) Bulkhead riveting System. This paper describes how benchmarks for flexible automated drilling and fastening are being achieved with the CPAC.
This SAE Aerospace Standard (AS) establishes the requirements for fluid fittings that combine both 24° cone flareless and 37° flared connections for use in all types of fluid systems.
ABSTRACT One of the main thrusts in current Army Science & Technology (S&T) activities is the development of occupant-centric vehicle structures that make the operation of the vehicle both comfortable and safe for the soldiers. Furthermore, a lighter weight vehicle structure is an enabling factor for faster transport, higher mobility, greater fuel conservation, higher payload, and a reduced ground footprint of supporting forces. Therefore, a key design challenge is to develop lightweight occupant-centric vehicle structures that can provide high levels of protection against explosive threats. In this paper, concepts for using materials, damping and other mechanisms to design structures with unique dynamic characteristics for mitigating blast loads are investigated. The Dynamic Response Index (DRI) metric [1] is employed as an occupant injury measure for determining the effectiveness of the each blast mitigation configuration that is considered. A model of the TARDEC Generic V-Hull structure comprises the vehicle considered in this study. The material properties and the configuration of the inner bulkheads that connect the outer V-shaped bottom with the inner floor are used as design parameters for reducing the DRI at a typical occupant location. In this particular example, it is demonstrated that the weight of the structure can be reduced by about ~12% and simultaneously, the DRI can be reduced by ~24%. This is achieved by creating an energy absorbing/decoupling mechanism between the outer hull, the inner floor, and the single degree of freedom upper torso system.
This Aerospace Information Report (AIR) contains information relative to stresses and loads developed in tubes, fittings and clamps caused by tube deflections encountered in misaligned installations.
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