Browse Topic: Pitch
In any human space flight program, safety of the crew is of utmost priority. In case of exigency in atmospheric flight, the crew is safely and quickly rescued from the launch vehicle using Crew Escape System (CES). CES is a critical part of the Human Space Flight which carries the crew module away from the ascending launch vehicle by firing its rocket motors (Pitch Motor (PM), Low altitude Escape Motor (LEM) and High altitude Escape Motor (HEM)). The structural loads experienced by the CES during the mission abort are severe as the propulsive, aerodynamic and inertial forces on the vehicle are significantly high. Since the mission abort can occur at anytime during the ascent phase of the launch vehicle, trajectory profiles are generated for abort at every one second interval of ascent flight period considering several combinations of dispersions on various propulsive parameters of abort motors and aero parameters. Depending on the time of abort, the ignition delay of PM, LEM and HEM
Potholes are a major cause of discomfort for riders and vehicle damage. The passive suspension systems which are used in the passenger vehicles are primarily reaction based. These can’t adapt to the changing road conditions which means the best ride quality and handling characteristics cannot be ensured for different driving situations. Passive suspension system also needs more maintenance due to its inability to reduce the impact of the road irregularities. In recent years, semi-active suspension systems have been developed to improve ride comfort and vehicle safety. This paper covers the integration of a semi-active suspension system with a road preview mechanism with a TATA car model to investigate its impact on ride comfort, handling characteristics and component loads in digital domain. A quarter car vehicle model is used to compare different active damping control strategies. The best strategy is selected and integrated in a full vehicle MBS model to gain deeper insight on ride
This document covers all metal, castellated, self-locking nuts made from alloy steel of the types identified under the Unified Numbering System as UNS G41300 and UNS G43400.
Existing integral flow-through balances have been limited to five-component force and moment measurements (normal and side force; pitch, yaw, and rolling moment) excluding a sixth desired force measurement: axial force. To enable key aerospace R&D applications, NASA’s Langley Research Center has developed a single-piece flow-through transducer design capable of measuring all six components adding in the Axial force measurement.
Smooth camber morphing aircraft offer increased control authority and improved aerodynamic efficiency. Smart material actuators have become a popular driving force for shape changes, capable of adhering to weight and size constraints and allowing for simplicity in mechanical design. University of Michigan, Ann Arbor, MI Uncrewed aerial vehicles (UAVs) are growing in popularity for both civilian and military applications, which makes improving their efficiency and adaptability for various aerial environments an attractive objective. Many studies pursue this goal using morphing techniques that incorporate shape changes not typically seen in traditional aircraft. Due to weight and volume constraints consistent with smaller flight vehicles, smart materials, such as macro fiber composites (MFCs), have been used to achieve the desired shape changes. Macro fiber composites are low-profile piezoelectric actuators which have gained substantial attention within the morphing aircraft community
The present numerical study investigates the design and analysis of a concept model Le Mans Grand Touring Prototype (LMGTP) car. Through analysis, aerodynamic pitch sensitivity and related factors are found to be detrimental to the straight-line stability of these high-speed race cars. Simulations are carried out on a commercial Computational Fluid Dynamics (CFD) tool for varying pitch angles of the car from −1° to +2.5°. For each pitch angle, steady-state pressure contours, velocity contours, and streamlines are presented. Additionally, coefficients and force values of lift and drag are calculated with the k-omega turbulence model implemented. Obtained numerical results are validated via Ahmed Body studies reported in the literature, and an average error deviation of 1.013% is exhibited. It is observed that lift force at the front axle increases with increasing pitch angles, leading to reduced pitch stability. At a peak of 2.5° pitch angle, the destabilizing lift force peaks at 1872 N
Auto-rickshaw is one of the most customary modes of transport in urban as well as rural areas of India. The safety of this vehicle is of prime concern. The braking system plays a vital role in the safety of any vehicle. This work is carried out in order to analyze the vehicle behavior during braking maneuver since the literature survey carried out had fewer details about the braking performance of Auto-rickshaw. Bajaj RE was chosen in particular for our study because it is widely used. Stopping distance analysis is utilized in order to estimate the vehicle braking performance. The straight-line braking performance is studied with the help of a 3-DOF mathematical model of the vehicle developed which includes the surge, heave and pitch motions. This model is formulated based on the Newtonian approach and is built on Simulink environment. The complete brake system is developed and coupled with the mathematical model. The Pacejka tire model is implemented in order to obtain accurate
Mobile Air Conditioning (MAC) system provides year round thermal comfort to the occupants inside vehicle cabin. In present scenario, 1D CAE simulation tools are widely used for MAC system design, component sizing, component selection and cool down performance prediction. The MAC component sizing and selection mainly depends on cooling load which varies with ambient conditions, occupancy, cabin size, geometry and material properties. Therefore, detailed modeling of vehicle cabin is essential during MAC system digital validation as it helps to predict performance across wide number of contributing factors. There are two different methods available in 1D Simulation for vehicle cabin modeling, viz. ‘simple cabin’ and ‘advance cabin’. With the simple cabin modeling approach, vehicle cabin is modelled as a group of lumped masses, which only enables prediction of average vent and average cabin temperatures. In advance cabin modeling approach, vehicle cabin is modelled more comprehensively
The aim of this study is to achieve the target transient posture of a vehicle according to the user’s steering operation. The target behavior was hypothesized to be a roll mode in the diving pitch, even during steering inputs on rough surfaces, in order to improve subjective evaluation. As a result of organizing the issues of feedforward control (FF) and feedback control (FB), we hypothesized that it would be appropriate to follow the ideal posture. The model following damping control (MFDC) was newly proposed by the authors as a solution to a control algorithm based on model-following control. The feature employs skyhook control (SH), which follows the deviation between the behavior of the reference model, which generates a target behavior with no input from the road surface, and the actual behavior of the vehicle. Numerical analyses were performed to verify the followability of the target behavior and the effect of roll damping performance. As a result of conducting actual vehicle
On the other side of the U.S. Army’s milestone multi-orbit antenna trials, the government’s modernization initiative took a timely big step toward unprecedented network resiliency just as adversarial threats reach a fever pitch. The Russian invasion in Ukraine has certainly raised the security stakes and intensified the need for simultaneous communications streams over a single platform, to keep connectivity flowing in the event of intentional jamming, cyberattacks, kinetic attacks, interference, and outages.
This work is aimed at conducting a computational study to find out the effect of vaneless space downstream of the Diffuser vane trailing edge, by varying the height of diffuser vane viz. 50%, 75%, and 100% diffuser height, on centrifugal stage performance. The considered centrifugal compressor stage in this study is NASA CC3 4:1 centrifugal stage. In all the cases diffuser leading-edge radius is the same. The compressor performance with full diffuser vane configuration (100% diffuser height) is computed and initially compared with test data. The diffuser vane height is then reduced to 50% and 75% of the original length from the diffuser leading edge. Hence, the diffuser leading-edge location remains the same as the original 100% diffuser vane height geometry whereas the location of the trailing edge changes according to vane height. Another part of the study is to model the 75% & 100% diffuser vane height with hub and shroud gaps respectively. The computational study is carried out
This SAE Standard covers the dimensioning technique, tolerances, and methods of measurement of V-ribbed belts and mating pulleys for use on automotive accessory drives.
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