Development of optimum clamp combinations for strap-down inertial measuring units with field replaceable sensors

Optimum clamp combinations for strap down inertial measuring units with field replaceable sensor

Strength Analysis of Flat Spring of the Resonant Vibro-Impact Module

International audienceThe rod model of the resonant vibro-impact module with an electromagnetic drive is considered. Construction's design implemented an asymmetrical elastic characteristic by one flat spring with two absolutely rigid intermediate supports. Eigenfrequency is defined for corresponding location intermediate supports based on the finite element method. Stress-strain state of the elastic element is graphically represented at the expense of static displacement of local mass. Contact task is considered and contact force between the flat spring and cylindrical support is calculated. Also, contact stiffness is determinate. The parameters of volumetric stress state of the contact, calculated analytically and by modeling in SolidWorks Simulation are shown. The dynamics of the vibro-impact rod system with kinematic's disturbance is modeled. Contact and equivalent stresses during operation of the vibro-impact rod system are determined. 1. Introduction. Vibro-impact systems are the basis of technological machines and processes of environments with challenging physical and mechanical characteristics. This is due the presence challenging modes as imposing the main and sub-harmonic oscillations, acceleration polyfrequency range by asymmetry of displacement of the operating mass. The resulting polyfrequency system generates wave processes, resonance phenomena and power conversion in environments more effective than harmonic movement law of worker mass. So, the use of frequency vibro-impact processes and systems is almost justified and promising. However, this requires challenging practical solutions for the implementation of nonlinear systems and special theoretical analysis to evaluation the relevant modes

Performance Exploration of Uncertain RF MEMS Switch Design with Uniform Meanders

The design of RF-MEMS Switch is useful for future artificial intelligence applications. Radio detection and range estimation has been employed with RF MEMS technology. Attenuators, limiters, phase shifters, T/R switches, and adjustable matching networks are components of RF MEMS. The proposed RF MEMS technology has been introduced in T/R modules, lenses, reflect arrays, sub arrays and switching beam formers. The uncertain RF MEMS switches have been faced many issues like switching and voltage alterations. This study aims in the direction of design, simulation, model along with RF MEMS switching analysis including consistent curving or meandering. The proposed RF MEMS Switch is a flexure form of the Meanders that attain minimal power in nominal voltage. Moreover, this research work highlights the materials assortment in case of beam along with signal-based dielectric. The performance analysis is demonstrated for various materials that have been utilized in the design purpose. Further, better isolation is accomplished at the range of -31dB necessary regarding 8.06V pull-in voltage through a spring constant valued at 3.588N/m, switching capacitance analysis has been found to be 103 fF at ON state and 7.03pF at OFF state and the proposed switch is optimized to work at 38GHz. The designed RF MEMS switch is giving 30% voltage improvement; switching frequency is improved by 21.32% had been attained, which are outperformance the methodology and compete with present technology

Studies in upper and lower atmosphere coupling

The theoretical and data-analytic work on upper and lower atmosphere coupling performed under a NASA Headquarters contract during the period April 1978 to March 1979 are summarized. As such, this report is primarily devoted to an overview of various studies published and to be published under this contract. Individual study reports are collected as exhibits. Work performed under the subject contract are in the following four areas of upper-lower atmosphere coupling: (1) Magnetosphere-ionosphere electrodynamic coupling in the aurora; (2) Troposphere-thermosphere coupling; (3) Ionosphere-neutral-atmosphere coupling; and (4) Planetary wave dynamics in the middle atmosphere

Mechanically Advantageous Wheelchair

This project will utilize a gear system to create a multispeed wheelchair. Multiple gears will allow users to adjust the speed of the wheelchair for appropriate scenarios. Our device will be modular and use a different gear mechanism than products currently in the marketplace

Holographic determination of mechanical properties and behaviour of materials

Bibliography: pages 116-122.This study, which was primarily experimental, was aimed at investigating the feasibility and development of experimental procedures using holographic interferometry to determine different material properties such as: i) Modulus of Elasticity (E) ii) Poisson's ratio (v) (which included a study into the Modulus of Rigidity. (G)) iii) creep behaviour at room temperature. The Elastic Modulus (E) was determined from the relationship E=v²p, where v is the velocity of a longitudinal wave propagating in a long rod and p is the density of the rod. The technique of double-exposure holographic interferometry was used to record longitudinal waves propagating in long brass and steel rods. The waves were initiated by striking the end of the rod with a pendulum. From the pulsed laser interferograms obtained, the distance travelled by the wave in a known time could be measured and thereby the velocity (v) could be calculated. Experimental results indicate that it is feasible fo use holographic interferometry when dynamically determining the Elastic Modulus. The values produced for brass and steel compared favourably with the ones obtained from the ultrasonic velocity technique

Design and Optimization of a SAE Baja Chassis

The purpose of the Society of Automotive Engineers (SAE) Baja Major Qualifying Project (MQP) was to analyze the pre-existing BSAE vehicles to determine flaws and design a new chassis that improved upon the previous designs. Analysis of preliminary and a near final design using Finite Element Analysis (FEA) led to modifications that produced the final chassis design. For suspension, the MQP determined that a double A-arm would be suitable in the front and a trailing or semi-trailing A-arm would be best in the rear. Each suspension was designed using specific constraints considered for optimal performance. A quote to manufacture and weld the frame was requested from VR3 and all documentation needed was created so that the manufacturing process could be completed during the upcoming summer

Soft Robot Locomotion via Mechanical Metamaterials: Application in Pipe Inspection

Pipe inspections are performed using large robots that utilize wheels or tracks for locomotion. Due to their large size, weight and hard exterior, these robots can occasionally cause damage to the pipe interiors during inspection. In addition, these pipe inspection robots struggle with the ability to move in a congested environment and adapt to obstacles or geometry changes within the pipe. This project investigates the capabilities of auxetic and conventional metamaterials to achieve locomotion in an enclosed channel through the different metamaterials reactions to an axial force. The resulting robot is capable of both horizontal and vertical locomotion. Computer simulation is used to confirm the metamaterials effective Poissons ratio through testing deformation under applied loads at small displacements. Physical testing of the soft-bodied robot is employed to demonstrate the force needed for movement and validate the auxetic and conventional metamaterial behavior. The extensive work serves as a proof of concept of auxetic metamaterials as a viable solution for less invasive movement through enclosed channels. Further work and alterations to the soft-bodied robot body may allow for future applications in realms such as medical device development

Subgrade resilient modulus testing at Tennessee instrumented pavement sites : standard and alternative methods

The resilient modulus is a basic material property that is used in the current 1993 AASHTO Pavement Design Guide to characterize subgrade soils under vehicular loading. The resilient modulus is used in the mechanistic empirical design method to determine strains at the top of the soil subgrade and to predict strains developed in the overlying asphalt layer. The new 2002 AASHTO Pavement Design Guide, which is moving toward a more rational mechanistic design method, will continue to use the resilient modulus to characterize the subgrade. The resilient modulus is often estimated since the standard repeated load triaxial test is time consuming, not always economically feasible, and a limited number of laboratories have the capability to perform the test. Therefore many researchers have made attempts to develop other methods. A laboratory investigation was conducted on four fine-grained subgrade soils from various instrumented pavement sites across Tennessee. For each of the four site soils, index properties were determined. Several specimens were remolded for each site at optimum moisture and density. Repeated load triaxial tests were performed in accordance with the AASHTO T 307-99 procedure. A log-log equation proposed by Schwartz (2001) and Andrei (1999) was used to model the results. The results from the triaxial tests were found to be consistent and the model was found to have a strong correlation with the data obtained. The resilient modulus was also determined using the ATM (alternative test method) developed by Li (1992). Improvements were made to the ATM prototype device and to the data processing. Calculations based on the single degree of freedom mass spring system produced inconsistent and counterintuitive results. The data was reanalyzed by integrating the complete time-acceleration history to find the recoverable strain. The results from the double integration technique produced values of resilient modulus greater than the repeated load triaxial test. However the results were more consistent than those obtained with the previous analysis approach. Loading rate effects and differing states of stress between the repeated load triaxial test and the ATM, can explain the difference in values. A hammer weight and reduction factor was recommended for using the ATM to estimate resilient modulus. It was suggested that additional testing be performed on ATM specimens without confinement and the effects of sample length be investigated. While it is easy to find resilient modulus values for different stress states with the ATM by using different combinations of drop heights and weights, the model developed in the standardized triaxial test is still preferable and more compatible with pavement design methods. With the automated data collection and analysis system, the need for an alternative method may not be as great

Attenuation of stress waves in single and multi-layered structures

Analytical and experimental studies were made of the attenuation of the stress waves during passage through single and multilayer structures. The investigation included studies on elastic and plastic stress wave propagation in the composites and those on shock mitigating material characteristics such as dynamic stress-strain relations and energy absorbing properties. The results of the studies are applied to methods for reducing the stresses imposed on a spacecraft during planetary or ocean landings