Recent advances in nonlinear passive vibration isolators

Concept and model of eddy current damper for vibration suppression of a beam

Energy dissipation prediction of particle dampers

A method is performed by an electronic device with a display and a touch-sensitive surface. The method includes: displaying a progress icon; while providing content with the electronic device: detecting a contact at a location that corresponds to the progress icon; detecting movement of the contact, wherein movement of the contact comprises a first component of movement on the touch-sensitive surface in a direction corresponding to movement on the display parallel to a first predefined direction and a second component of movement on the touch-sensitive surface in a direction corresponding to movement on the display perpendicular to the first predefined direction; and, while continuing to detect the contact on the touch-sensitive surface, moving the current position within the content at a scrubbing rate, wherein the scrubbing rate decreases as the second component of movement on the touch-sensitive surface increases.

Device, method, and graphical user interface for moving a current position in content at a variable scrubbing rate

The present invention provides meta-materials with an actively controllable mechanical property. The meta-material includes a deformable structure and a set of activation elements. The activation elements are controllable between multiple states. The meta-material includes a first value for a mechanical property when one or more of the activation elements is in the first activation state and includes a second value for the mechanical property when the activation elements have been activated to the second activation state. In one aspect, the meta-material resembles a composite material where the connectivity between the component materials or shape and arrangement of the component materials is dynamically controllable so as to affect a mechanical property of the meta-material.

Mechanical meta-materials

An adaptive passive damping system is described for the low-order modes of spacecraft large solar arrays. The work is motivated by the stringent sensor pointing requirements of several current satellite programs. Realistic system-level requirements are developed relating pointing error of a representative spacecraft to damping of its solar arrays. Performance is specified in terms of gain envelopes on open-loop frequency response functions for the structure with dampers. A family of remotely tunable, eddy-current tuned mass dampers (TMDs) is described which suppress several modes of a 430-lb solar array simulator in the frequency range of 0.1 - 1.0 Hz. The magnetic dampers are ground demonstration units, suitable for use in 1-G, but are designed around traceable, system-level dynamic requirements. The damper design is intended from the outset to be evolved into flight hardware. Tuning of TMD natural frequency and damping ratio to their optimum values is demonstrated through component-level base transmissibility test results.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Demonstration of solar array vibration suppression

This paper describes the design of a solar array damper that will be built into each of two new solar arrays to be installed on the Hubble Space Telescope (HST) during Servicing Mission 3. On this mission, currently scheduled for August 2000, two 'rigid' solar array wings will replace the 'flexible' wings currently providing power for HST. In addition to increased power, the new arrays will provide the capability for HST to survive re-boost to a higher orbit. The objective of the damper is to reduce the dynamic interaction of these new wings with the Telescope spacecraft. The damper, which is integral to the mast of the solar array, suppresses the fundamental bending modes of the deployed wings at 1.2 Hz (in-plane) and 1.6 Hz (out-of-plane). With the flight version of the damper, modal damping of 2.3% of critical is expected over the temperature range of -4 degrees Celsius to 23 degrees Celsius with a peak damping level of 3.9%. The unique damper design, a combination of titanium spring and viscoelastic damper, was developed using a system finite element model of the solar array wing and measured viscoelastic material properties. Direct complex stiffness (DCS) testing was performed to characterize the frequency- and temperature-dependent behavior of the damper prior to fixed- base modal testing of the wing at NASA/Goddard Space Flight Center (GSFC).© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Hubble Space Telescope solar array damper

A passive, multi-axis, highly damped, shock load isolation mount which can serve as a complete one-piece mount, particularly of a spacecraft to its launch vehicle or launch vehicle adaptor structure, or can serve in multiplicity as necessary to provide a complete shock load isolation mounting system. When used as a one-piece mount or used in multitude as a system, the invention provides substantial reduction in the shock load transmission to a payload from its support base for both axial loads and lateral loads. The unique multi-layered, opposed beam, contorted load path flexure design combined with a shear wall type constrained layer damping treatment provides substantial shock load isolation in a durable, reliable, lightweight, and compact form.

Passive, multi-axis, highly damped, shock isolation mounts for spacecraft

Spacecraft carry instruments and sensors that gather information from distant points, for example, from the Earth's surface several hundred kilometers away. Small vibrations on the spacecraft can reduce instrument effectiveness significantly. Vibration isolation system are one means of minimizing the jitter of sensitive instruments. This paper describes one such system, the Satellite Ultraquiet Isolation Technology Experiment (SUITE). SUITE is a piezoelectric-based technology demonstration scheduled to fly in 2000 on PICOSat, a microsatellite fabricated by Surrey Satellite Technology, Ltd. Control from the ground station is planned for the first year after launch. SUITE draws on technology from previous research programs as well as a commercial piezoelectric vibration isolation system. The paper details the features of SUITE, with particular emphasis on the active hexapod assembly. A description of the PICOSat spacecraft and the other considerations preceding the development of the flight hardware begins the paper. Experimental goals are listed. The mechanical and electromechanical construction of the SUITE hexapod assembly is described, including the piezoelectric actuators, motion sensors, and electromagnetic actuators. The data control system is also described briefly, including the digital signal processor and spacecraft communication. The main features of the software used for real-time control and the supporting Matlab software used for control system development and data processing are summarized.

Satellite ultraquiet isolation technology experiment (SUITE): electromechanical subsystems

As vibration suppression technology has matured, the application of viscoelastic materials in passive damping mechanisms has proven to be a reliable means toward improved structural dynamics This paper discusses general steps required in characterization of viscoelastic damping elements and presents several successful passive damping devices as examples of the approach Sample devices include a damper for the Hubble Space Telescope Solar Array 3, a damped strut built for the FORTE satellite, a viscoelastic isolator, and a cocured viscoelastic/composite strut When damping is built into a structure with a damped element, it is necessary to measure the element stiffness to understand its effect on the system dynamics The stiffness measurement is complex because of the level of damping The complex stiffness function, with both real and imaginary components, characterizes the behavior of a damping device, a damped structural element, or a sample of viscoelastic material Stiffness characterization of structural elements with viscoelastic damping is presented in terms of real stiffness and loss (imaginary stiffness/real stiffness)

Complex stiffness measurement of vibration-damped structural elements

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Scott C. Pendleton

Author Tools

Chat about Author