Broadband Waveguide

A broadband waveguide comprising at least one filament configured to transmit a signal therethrough. The broad-band waveguide may include one or more reflection suppression techniques including a damping material coupled to at least a portion of the at least one filament and/or at least one reflection point configured thereon. The waveguide may further including a cladding material coupled to the at least one filament. The at least one filament may be coupled to a securing element configured to couple to a surface. The at least one filament may be coupled to a sensor configured to sense the transmitted signal. 15-. (canceled)6. A broadband waveguide configured to communicate a signal , comprising:at least one filament configured to transmit the signal including a first end, a second end, and a length between the first and second ends;a damping material at least partially engaging at least a portion of the at least one filament having a defined length based at least in part on an application of the broadband waveguide.7. The broadband waveguide of claim 6 , wherein the defined length is greater than about 0.5 inches.8. The broadband waveguide of claim 6 , wherein the damping material comprises polyolefin shrink tubing.9. The broadband waveguide of claim 6 , wherein the damping material comprises a first layer having a first length and a second layer having a second length different than the first length.10. The broadband waveguide of claim 6 , wherein the second end reflects the signal as a reflected signal and the defined length of the damping material is configured to absorb at least a portion of energy associated with the reflected signal to thereby at least partially suppress the reflected signal.11. A broadband waveguide configured to communicate a signal claim 6 , comprising:at least one filament configured to transmit the signal including a first end, a second end, and a length between the first and second ends;a cladding material surrounding at least a ...

Composite Active Waveguide Temperature Sensor for Harsh Environments

A composite active waveguide temperature sensor () incorporates a first, sensor portion () formed of an environment-resistant material such as ceramic coupled through an ultrasonically-transparent bond () to a second, waveguide portion () formed of an ultrasonically-transmissive material such as a metallic filament wire. By doing so, the sensor portion () may be positioned within a harsh environment and subjected to a temperature to be measured, and the waveguide portion () may be used to propagate ultrasonic energy to and/or from the sensor portion () to a location distal from the harsh environment for measurement of the temperature. The ultrasonically-transparent bond () between these portions () limits attenuation of and the introduction of reflections and other noise to an ultrasonic signal propagated across the bond (). 1. A composite sensor comprising:a sensor portion formed of an environment-resistant material for sensing an environmental condition in a harsh environment; anda waveguide portion formed of an ultrasonically-transmissive material and coupled to the sensor portion through an ultrasonically-transparent bond.2. The sensor of claim 1 , wherein the environment-resistant material is a ceramic material.3. The sensor of claim 1 , wherein the environment-resistant material is a refractory material.4. The sensor of claim 1 , wherein the ultrasonically-transmissive material is a metal.5. The sensor of claim 4 , wherein the ultrasonically-transmissive material comprises a steel wire filament.6. The sensor of claim 1 , further comprising a cone coupling the waveguide portion to a transducer at an end opposite to the ultrasonically-transparent bond.7. The sensor of claim 1 , wherein the ultrasonic bond comprises a bond formed by brazing claim 1 , soldering claim 1 , adhesive claim 1 , press-fit claim 1 , or mechanical fastening.8. The sensor of claim 1 , wherein the harsh environment is a high temperature environment.9. The sensor of claim 1 , wherein the ...

Active Waveguide Excitation and Compensation

An environmental condition may be measured with a sensor () including a wire () having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone () may be used to couple ultrasonic energy between a waveguide wire () and a transducer (). 1. A method of measuring an environmental condition with a sensor of the type that includes a wire having an ultrasonic signal transmission characteristic that varies in response to the environmental condition , the method comprising:sensing ultrasonic energy propagated through the wire using multiple types of propagation; andseparating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation.2. The method of claim 1 , further comprising exciting the wire using the multiple types of propagation.3. The method of claim 2 , wherein exciting the wire using the multiple types of propagation comprises exciting the wire at multiple excitation frequencies.4. The method of claim 3 , wherein exciting the wire at multiple excitation frequencies comprises exciting the wire at a first excitation frequency that propagates ultrasonic energy primarily as a longitudinal wave claim 3 , and exciting the wire at a second excitation frequency that propagates ultrasonic energy primarily as a shear wave.5. The method of claim 1 , wherein separating the ...

PRELOADED STRUT

A strut suitable for use in parallel manipulator and other applications utilizes an actuation member that is subjected to a quasi-static axial tensioning force to effectively preload the strut to provide axial stiffness and bending flexibility at one or more ends of the strut. 1. A strut , comprising:a rigid tensioning member;a compression spring disposed proximate a first end of the rigid tensioning member; andan actuation member extending through the rigid tensioning member and the compression spring, the actuation member being substantially axially rigid under tension and at least a portion of the actuation member extending through the compression spring being substantially flexible in bending or compression, wherein the actuation member is preloaded through the compression spring and the rigid tensioning member with a quasi-static axial tensioning force such that the actuation member remains substantially axially rigid in response to application of an axial compressive force to the strut that is less than the quasi-static tensioning force.2. The strut of claim 1 , further comprising a tensioner coupled to a first end of the actuation member proximate the compression spring to apply the quasi-static tensioning force to the actuation member.3. The strut of claim 2 , wherein the first end of the actuation member is threaded claim 2 , and wherein the tensioner comprises a nut that is threadably engaged with the first end of the actuation member.4. The strut of claim 1 , wherein the rigid tensioning member comprises a rigid tensioning tube.5. The strut of claim 4 , wherein the rigid tensioning tube comprises a carbon fiber tube.6. The strut of claim 1 , wherein the compression spring comprises an elastomeric spring.7. The strut of claim 1 , wherein the compression spring comprises a coiled spring.8. The strut of claim 1 , wherein the compression spring comprises a conical spring washer.9. The strut of claim 1 , wherein the actuation member comprises a braided metal ...

DAMAGE DETECTION FOR MECHANICAL WAVEGUIDE SENSOR

A sensor with a mechanical waveguide maybe characterized using test ultrasonic signals to generate a baseline signature, and the baseline signature may later be used to detect faults in the sensor. 1. A method of monitoring a sensor of the type including a mechanical waveguide including an ultrasonically-transmissive material , the method comprising:receiving an ultrasonic signal propagated through the waveguide in response to ultrasonic stress waves introduced to the waveguide;comparing the received ultrasonic signal to a baseline signature for the sensor; andidentifying a fault in the sensor based upon the comparison.2. The method of claim 1 , wherein the sensor further includes an ultrasonic transducer coupled to the waveguide and configured to propagate the ultrasonic stress waves through the waveguide and a receiver coupled to the waveguide and configured to receive the ultrasonic signal propagated through the waveguide in response to the ultrasonic stress waves generated by the ultrasonic transducer claim 1 , and wherein identifying the fault in the sensor includes identifying a fault in the ultrasonic transducer or the receiver based on the comparison.3. The method of claim 2 , wherein the sensor further includes one or more electronic components claim 2 , the one or more components including an analog to digital converter claim 2 , a digital to analog converter and/or an amplifier claim 2 , and wherein identifying the fault in the sensor includes identifying a fault in the one or more components based on the comparison.3. The method of claim 1 , wherein identifying the fault in the sensor includes identifying a fault in the waveguide based upon the comparison.4. The method of claim 3 , wherein identifying the fault in the waveguide includes identifying an abrasion claim 3 , erosion claim 3 , corrosion or buildup of material from an environment on the waveguide based upon the comparison.5. The method of claim 3 , wherein identifying the fault in the waveguide ...

DISTRIBUTED ACTIVE MECHANICAL WAVEGUIDE SENSOR WITH DAMPING

An active mechanical waveguide including an ultrasonically-transmissive material and a plurality of reflection points defined along a length of the waveguide may be dampened using a damping device on a plurality of support members for the waveguide and/or using a damping device on the waveguide itself, and variable spacing of support members and/or constant tensioning of the waveguide may also be used. 1. A sensor for sensing an environmental condition in an environment , comprising:an active mechanical waveguide including an ultrasonically-transmissive material and a plurality of reflection points defined along a length of the waveguide to define a plurality of sensing regions along the waveguide;a plurality of support members supporting the waveguide along at least a portion of the length of the waveguide; anda damping device disposed between the waveguide and each of the plurality of support members to dampen environment-induced vibrations of the waveguide.2. The sensor of claim 1 , wherein the environment is disposed within a gas turbine engine claim 1 , and wherein the environment-induced vibrations include vibrations of the gas turbine engine claim 1 , vibrations induced by rotation of a blade within the gas turbine engine and/or vibration due to excitation within the gas turbine engine.3. The sensor of claim 1 , further comprising:an ultrasonic transducer coupled to the waveguide and configured to propagate ultrasonic stress waves through the waveguide; andcontrol logic coupled to the ultrasonic transducer and configured to determine a value of an environmental condition for each of the plurality of sensing regions based upon an ultrasonic signal propagated through the waveguide in response to the ultrasonic stress waves generated by the ultrasonic transducer.4. The sensor of claim 1 , wherein the damping device includes a viscoelastic material.5. The sensor of claim 4 , wherein each of the plurality of support members is cantilevered and extends generally ...

Broadband Waveguide

A broadband waveguide comprising at least one filament configured to transmit a signal therethrough. The broadband waveguide may include one or more reflection suppression techniques including a damping material coupled to at least a portion of the at least one filament and/or at least one reflection point configured thereon. The waveguide may further including a cladding material coupled to the at least one filament. The at least one filament may be coupled to a securing element configured to couple to a surface. The at least one filament may be coupled to a sensor configured to sense the transmitted signal.

METHOD OF DETERMINING THE LEFT EIGENVECTORS IN A FLOWING CORIOLIS FLOWMETER

A method and apparatus for a flowmeter () is provided. The method comprises the steps of placing a material in a flow tube (′) while exciting a vibration mode of the flow tube (′). Exciting the vibration mode of the flow tube (′) comprises the steps of periodically driving a first driver (L) with a first signal and periodically driving a second driver (R) with a second signal, wherein the second driver (R) is driven essentially in phase with the first driver (L), but wherein the first driver's (L) drive amplitude modulated signal reaches a maximum amplitude when the second driver's (R) drive modulated signal reaches a minimal amplitude, and the first driver's (L) drive amplitude modulated signal reaches a minimum amplitude when the second driver's (R) drive amplitude modulated signal reaches a maximum amplitude. The method also comprises the steps of measuring the relative phase between a first pickoff (L) and a second pickoff (R) and determining a relative phase of a right eigenvector for the flow tube (′). 1. A method , comprising: periodically driving a first driver with a first signal;', "periodically driving a second driver with a second signal, wherein the second driver is driven essentially in phase with the first driver, wherein the first driver's drive amplitude modulated signal reaches a maximum amplitude when the second driver's drive amplitude modulated signal reaches a minimal amplitude, and the first driver's drive amplitude modulated signal reaches a minimum amplitude when the second driver's drive amplitude modulated signal reaches a maximum amplitude;"], 'placing a material in a flow tube while exciting a vibration mode of the flow tube, wherein exciting the vibration mode of the flow tube comprises the steps ofmeasuring the relative phase between a first pickoff and a second pickoff; anddetermining a relative phase of a right eigenvector for the flow tube.2. The method of claim 1 , further comprising:measuring a frequency shift that occurs between ...

Driver for oscillating a vibrating conduit

A process parameter measurement device, and in particular a Coriolis mass flowmeter or vibrating tube densimeter, having a driver or drivers for inducing oscillation of at least one conduit. The drivers are attached at locations along the vibrating conduit selected to influence certain modes of interest. A driver is located near an area of maximum amplitude of a desired vibration mode and near an area of minimum amplitude of an undesired vibration mode. Various known experimental modal analysis or modeling techniques are used to determine the appropriate locations for one or more drivers. Multiple drivers located according to the present invention are used to influence, i.e. excite or suppress, multiple modes. In addition, multiple, separate drive circuits produce multiple, electronically isolated drive signals for delivering greater total power to the vibrating conduit.

Broadband waveguide

A broadband waveguide comprising at least one filament configured to transmit a signal therethrough. The broadband waveguide may include one or more reflection suppression techniques including a damping material coupled to at least a portion of the at least one filament and/or at least one reflection point configured thereon. The waveguide may further including a cladding material coupled to the at least one filament. The at least one filament may be coupled to a securing element configured to couple to a surface. The at least one filament may be coupled to a sensor configured to sense the transmitted signal.

Vibrating conduit and methods for generating compensated mass flow estimates

A process parameter associated with a material contained in a conduit is estimated by estimating a real normal modal residual flexibility component associated with a real normal mode of motion of the conduit. A plurality of motion signals representing motion of the conduit is received. A residual-flexibility-compensated estimate of mass flow is generated from the received plurality of motion signals and the estimated real normal modal residual flexibility component. Related apparatus and computer program products are also described.

Generalized modal space drive control system for a vibrating tube process parameter sensor

A drive system is taught for controlling the modal content of drive signals used to excite drives on a vibrating conduit, such as in a Coriolis mass flowmeter or a vibrating tube densimeter. Motion signals are obtained from spatially distinct feedback sensors. A modal response signal corresponds to one of the vibration modes at which the vibrating conduit is excited. Modal response signals are input to a drive channel, each having a separate processing channel. Within each channel, the respective modal response signal is compared to a desired modal response setpoint. The resulting mode error signal is amplified to produce a modal excitation signal for each mode. The modal excitation signal, representing the modal excitation applied, is transformed from the modal domain back to the physical domain and mapped to physical locations of the drives. The resulting drive signals are applied to the drives to excite the conduit.

Structural control and monitoring using adaptive spatio-temporal filtering

A method and apparatus for decoupling complex multiple degree-of-freedom (MDOF) responses measured on linear dynamic systems into constituent single degree-of-freedom (SDOF) modal responses. A data acquisition and processing system periodically samples response signals generated by a plurality of sensors spaced at various locations on a linear dynamic system. The processing system calculates a plurality of sets of spatio-temporal filter coefficients based upon time-shifted digitized response signals. A synthesizer applies the spatio-temporal filter coefficients to the response signals, thereby generating synthesized signals representing decoupled SDOF responses of the linear dynamic system. Means are provided for receiving input signals representing a plurality of excitation inputs and for calculating input influence coefficients based upon the time-shifted digitized response signals and the excitation input signals.

Active waveguide excitation and compensation

An environmental condition may be measured with a sensor ( 10 ) including a wire ( 20 ) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone ( 200, 210 ) may be used to couple ultrasonic energy between a waveguide wire ( 202, 212 ) and a transducer ( 204, 214 ).

Oscillatory trigger and combined collection for use in coriolis flow meters and method to operate them

"ACIONADOR OSCILATóRIO E COLETA COMBINADOS PARA USO EM MEDIDORES DE FLUXO CORIOLIS E MéTODO PARA OPERAR OS MESMOS" Trata-se de um acionador de vibração oscilatório (104) que é conectado de forma que possa ser operado conectado com um medidor de fluxo Coriolis (10) para uso em vibrar os tubos de fluxo do medidor (103A e 103B). Os componentes eletrónicos do medidor (20) contém um circuito mimético (414, 802, 902) que permite o uso do acionador como uma coleta de sinal que proporciona uma medida da força eletromotora de retorno para uso em calcular a taxa do fluxo de massa e a densidade a partir do medidor de fluxo Coriolis. O circuito mimético contém uma bobina analógica (604) e o imã (600) que facilitam a media da força eletromotora de retorno, ou o circuito mimético pode compreender dispositivos digitais (804, 806, 808, 904, 906).

Vibrating conduit and methods for generating compensated mass flow estimates

Vibrating conduit and methods for generating compensated mass flow estimates

Active Waveguide Excitation and Compensation

An environmental condition may be measured with a sensor ( 10 ) including a wire ( 20 ) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone ( 200, 210 ) may be used to couple ultrasonic energy between a waveguide wire ( 202, 212 ) and a transducer ( 204, 214 ).

Combined pickoff and oscillatory driver for use in coriolis flowmeters and method of operating the same

An oscillatory vibration driver (104) is operably connected to a Coriolis flowmeter (10) for use in vibrating the meter flow tubes (103A and 103B). The meter electronics (20) contain a mimetic circuit (414, 802, 902) that permits use of the driver as a signal pickoff which provides a measurement of back electromotive force for use in calculating mass flow rate and density from the Coriolis flowmeter. The mimetic circuit contains an analog coil (604) and magnet (600) that facilitate the measurement of back electromotive force, or the mimetic circuit may comprise digital means (804, 806, 808, 904, 906).

Combined pickoff and oscillatory driver for use in coriolis flowmeters and method of operating the same

An oscillatory vibration driver (104) is operably connected to a Coriolis flowmeter (10) for use in vibrating the meter flow tubes (103A and 103B). The meter electronics (20) contain a mimetic circuit (414, 802, 902) that permits use of the driver as a signal pickoff which provides a measurement of back electromotive force for use in calculating mass flow rate and density from the Coriolis flowmeter. The mimetic circuit contains an analog coil (604) and magnet (600) that facilitate the measurement of back electromotive force, or the mimetic circuit may comprise digital means (804, 806, 808, 904, 906).

Vibrating conduit parameter sensors, methods and computer program products for generating residual-flexibility-compensated mass flow estimates

A process parameter associated with a material contained in a conduit is estimated by estimating a real normal modal residual flexibility component associated with a real normal mode of motion of the conduit. A plurality of motion signals representing motion of the conduit is received. A residual-flexibility-compensated estimate of mass flow is generated from the received plurality of motion signals and the estimated real normal modal residual flexibility component. Related apparatus and computer program products are also described.

A method and apparatus for measuring flow through a conduit by measuring the coriolis coupling between two vibration modes

Driver for oscillating a vibrating conduit

Damage detection for mechanical waveguide sensor

A sensor with a mechanical waveguide may be characterized using test ultrasonic signals to generate a baseline signature, and the baseline signature may later be used to detect faults in the sensor.

Self-characterizing vibrating conduit parameter sensors

A self-characterizing vibrating conduit sensor (5) for measuring a process parameter in a material processing system (1) includes a conduit (103A-103B) configured to contain material from the material processing system (1) and a plurality of motion transducers (105-105') operative to produce a plurality of motion signals representing motion at a plurality of locations on the conduit (103A-103B). A modal parameter estimator (30) is configured to receive the plurality of motion signals and operative to estimate a modal parameter from the received plurality of motion signals. The modal parameter, e.g., a modal filter parameter or a force projection parameter, relates behavior of the conduit to behavior of a single degree of freedom (SDOF) system. A process parameter estimator 40 is configured to receive the plurality of motion signals, responsive to the modal parameter estimator and operative to estimate a process parameter associated with a material in the conduit from the received plurality of motion signals according to the estimated modal parameter. Techniques for estimating a modal parameter include a modified reciprocal modal vector (MRMV) estimation technique and an adaptive modal filtering technique.

Self-characterizing vibrating conduit parameter sensors

A self-characterizing vibrating conduit sensor (5) for measuring a process parameter in a material processing system (1) includes a conduit (103A-103B) configured to contain material from the material processing system (1) and a plurality of motion transducers (105-105') operative to produce a plurality of motion signals representing motion at a plurality of locations on the conduit (103A-103B). A modal parameter estimator (30) is configured to receive the plurality of motion signals and operative to estimate a modal parameter from the received plurality of motion signals. The modal parameter, e.g., a modal filter parameter or a force projection parameter, relates behavior of the conduit to behavior of a single degree of freedom (SDOF) system. A process parameter estimator 40 is configured to receive the plurality of motion signals, responsive to the modal parameter estimator and operative to estimate a process parameter associated with a material in the conduit from the received plurality of motion signals according to the estimated modal parameter. Techniques for estimating a modal parameter include a modified reciprocal modal vector (MRMV) estimation technique and an adaptive modal filtering technique.

Generalized modal space drive control system for a vibrating tube process parameter sensor

A drive system is taught for controlling the modal content of drive signals used to excite drives on a vibrating conduit, such as in a Coriolis mass flowmeter or a vibrating tube densimeter. Motion signals are obtained from spatially distinct feedback sensors. A modal response signal corresponds to one of the vibration modes at which the vibrating conduit is excited. Modal response signals are input to a drive channel, each having a separate processing channel. Within each channel, the respective modal response signal is compared to a desired modal response setpoint. The resulting mode error signal is amplified to produce a modal excitation signal for each mode. The modal excitation signal, representing the modal excitation applied, is transformed from the modal domain back to the physical domain and mapped to physical locations of the drives. The resulting drive signals are applied to the drives to excite the conduit.

Self-characterizing vibrating conduit parameter sensors

A self-characterizing vibrating conduit sensor (5) for measuring a process parameter in a material processing system (1) includes a conduit (103A-103B) configured to contain material from the material processing system (1) and a plurality of motion transducers (105-105') operative to produce a plurality of motion signals representing motion at a plurality of locations on the conduit (103A-103B). A modal parameter estimator (30) is configured to receive the plurality of motion signals and operative to estimate a modal parameter from the received plurality of motion signals. The modal parameter, e.g., a modal filter parameter or a force projection parameter, relates behavior of the conduit to behavior of a single degree of freedom (SDOF) system. A process parameter estimator 40 is configured to receive the plurality of motion signals, responsive to the modal parameter estimator and operative to estimate a process parameter associated with a material in the conduit from the received plurality of motion signals according to the estimated modal parameter. Techniques for estimating a modal parameter include a modified reciprocal modal vector (MRMV) estimation technique and an adaptive modal filtering technique.

Distributed active mechanical waveguide sensor driven at multiple frequencies and including frequency-dependent reflectors

An active mechanical waveguide including an ultrasonically-transmissive material and a plurality of reflection points defined along a length of the waveguide may be driven at multiple resonant frequencies to sense environmental conditions, e.g., using tracking of a phase derivative. In addition, frequency-dependent reflectors may be incorporated into an active mechanical waveguide, and a drive frequency may be selected to render the frequency-dependent reflectors substantially transparent.

Active waveguide excitation and compensation

An environmental condition may be measured with a sensor (10) including a wire (20) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone (200, 210) may be used to couple ultrasonic energy between a waveguide wire (202, 212) and a transducer (204, 214).

Broadband waveguide

A broadband waveguide (10) incorporates various reflection suppression techniques to reduce reflections in signals communicated thereby. The waveguide includes one or more filaments (12) that each include a first and second end (14, 16). A first matrix (18) may be configured proximate the first end(s) while a second matrix (20) may be configured proximate an intermediate location between the first and second ends. A damping material (22b) may cover a portion of the filament(s) that extends from the second matrix to the second end(s) (including the second end(s) themselves) and/or the second end(s) of the filament(s) is/are shaped to at least partially suppress reflections of the signal therefrom. When configured with multiple filaments, at least two of the filaments may have differing lengths that extend from the second matrix and also operate to at least partially suppress reflections of a signal.

Broadband waveguide

A broadband waveguide (10) incorporates various reflection suppression techniques to reduce reflections in signals communicated thereby. The waveguide includes one or more filaments (12) that each include a first and second end (14, 16). A first matrix (18) may be configured proximate the first end(s) while a second matrix (20) may be configured proximate an intermediate location between the first and second ends. A damping material (22b) may cover a portion of the filament(s) that extends from the second matrix to the second end(s) (including the second end(s) themselves) and/or the second end(s) of the filament(s) is/are shaped to at least partially suppress reflections of the signal therefrom. When configured with multiple filaments, at least two of the filaments may have differing lengths that extend from the second matrix and also operate to at least partially suppress reflections of a signal.

Preloaded strut

A strut suitable for use in parallel manipulator and other applications utilizes an actuation member that is subjected to a quasi-static axial tensioning force to effectively preload the strut to provide axial stiffness and bending flexibility at one or more ends of the strut.