A cantilever is a rigid
structural element Structural elements are used in structural analysis to split a complex structure into simple elements. Within a structure, an element cannot be broken down (decomposed) into parts of different kinds (e.g., beam or column).
Structural elements can ...
that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilever can be formed as a
beam
Beam may refer to:
Streams of particles or energy
*Light beam, or beam of light, a directional projection of light energy
**Laser beam
*Particle beam, a stream of charged or neutral particles
**Charged particle beam, a spatially localized grou ...
, plate,
truss
A truss is an assembly of ''members'' such as beams, connected by ''nodes'', that creates a rigid structure.
In engineering, a truss is a structure that "consists of two-force members only, where the members are organized so that the assembl ...
, or
slab
Slab or SLAB may refer to:
Physical materials
* Concrete slab, a flat concrete plate used in construction
* Stone slab, a flat stone used in construction
* Slab (casting), a length of metal
* Slab (geology), that portion of a tectonic plate that i ...
.
When subjected to a
structural load
A structural load or structural action is a force, deformation, or acceleration applied to structural elements. A load causes stress, deformation, and displacement in a structure. Structural analysis, a discipline in engineering, analyzes the ef ...
at its far, unsupported end, the cantilever carries the load to the support where it applies a
shear stress
Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. ''Normal stress'', on the ot ...
and a
bending moment
In solid mechanics, a bending moment is the reaction induced in a structural element when an external force or moment is applied to the element, causing the element to bend. The most common or simplest structural element subjected to bending mome ...
.
Cantilever construction allows overhanging structures without additional support.
In bridges, towers, and buildings
Cantilevers are widely found in construction, notably in
cantilever bridge
A cantilever bridge is a bridge built using structures that project horizontally into space, supported on only one end (called cantilevers). For small footbridges, the cantilevers may be simple beam (structure), beams; however, large cantilever ...
s and
balconies
A balcony (from it, balcone, "scaffold") is a platform projecting from the wall of a building, supported by columns or Corbel, console brackets, and enclosed with a balustrade, usually above the ground floor.
Types
The traditional Malta, Malte ...
(see
corbel
In architecture, a corbel is a structural piece of stone, wood or metal jutting from a wall to carry a superincumbent weight, a type of bracket. A corbel is a solid piece of material in the wall, whereas a console is a piece applied to the s ...
). In cantilever bridges, the cantilevers are usually built as pairs, with each cantilever used to support one end of a central section. The
Forth Bridge
The Forth Bridge is a cantilever railway bridge across the Firth of Forth in the east of Scotland, west of central Edinburgh. Completed in 1890, it is considered a symbol of Scotland (having been voted Scotland's greatest man-made wonder in ...
in
Scotland
Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...
is an example of a cantilever
truss bridge
A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. The connected elements (typically straight) may be stressed from tension, compression, or ...
. A cantilever in a traditionally
timber framed
Timber framing (german: Holzfachwerk) and "post-and-beam" construction are traditional methods of building with heavy timbers, creating structures using squared-off and carefully fitted and joined timbers with joints secured by large wooden ...
building is called a
jetty
A jetty is a structure that projects from land out into water. A jetty may serve as a breakwater, as a walkway, or both; or, in pairs, as a means of constricting a channel. The term derives from the French word ', "thrown", signifying somet ...
or
forebay. In the southern United States, a historic barn type is the cantilever barn of
log construction.
Temporary cantilevers are often used in construction.
The partially constructed structure creates a cantilever, but the completed structure does not act as a cantilever.
This is very helpful when temporary supports, or
falsework
Falsework consists of temporary structures used in construction to support a permanent structure until its construction is sufficiently advanced to support itself. For arches, this is specifically called centering. Falsework includes temporary su ...
, cannot be used to support the structure while it is being built (e.g., over a busy roadway or river, or in a deep valley).
Therefore, some
truss arch bridge
A truss arch bridge combines the elements of the truss bridge and the arch bridge. The actual resolution of forces will depend upon the design. If no horizontal thrusting forces are generated this becomes an arch-shaped truss, essentially a bent b ...
s (see
Navajo Bridge
Navajo Bridge is the name of twin steel spandrel arch bridges that cross the Colorado River in the Grand Canyon National Park (near Lee's Ferry, Lees Ferry) in northern Coconino County, Arizona, Coconino County, Arizona, United States. The newer ...
) are built from each side as cantilevers until the spans reach each other and are then jacked apart to stress them in compression before finally joining.
Nearly all
cable-stayed bridges
A cable-stayed bridge has one or more ''towers'' (or ''pylons''), from which cables support the bridge deck. A distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern o ...
are built using cantilevers as this is one of their chief advantages.
Many box girder bridges are built
segmentally, or in short pieces.
This type of construction lends itself well to balanced cantilever construction where the bridge is built in both directions from a single support.
These structures rely heavily on
torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
and rotational equilibrium for their stability.
In an architectural application,
Frank Lloyd Wright
Frank Lloyd Wright (June 8, 1867 – April 9, 1959) was an American architect, designer, writer, and educator. He designed more than 1,000 structures over a creative period of 70 years. Wright played a key role in the architectural movements o ...
's
Fallingwater
Fallingwater is a house designed by the architect Frank Lloyd Wright in 1935 in the Laurel Highlands of southwest Pennsylvania, about southeast of Pittsburgh in the United States. It is built partly over a waterfall on Bear Run in the Mill R ...
used cantilevers to project large balconies.
The East Stand at
Elland Road
Elland Road is a football stadium in Beeston, Leeds, West Yorkshire, England, which has been the home of Premier League club Leeds United since the club's formation in 1919. The stadium is the 14th largest football stadium in England.
The g ...
Stadium in Leeds was, when completed, the largest cantilever stand in the world holding 17,000 spectators.
The
roof
A roof ( : roofs or rooves) is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temper ...
built over the stands at
Old Trafford
Old Trafford () is a football stadium in Old Trafford, Greater Manchester, England, and the home of Manchester United. With a capacity of 74,310 it is the largest club football stadium (and second-largest football stadium overall after Wemb ...
uses a cantilever so that no supports will block views of the field.
The old (now demolished)
Miami Stadium
Miami Stadium (later officially known as Bobby Maduro Miami Stadium) was a baseball stadium in Miami, Florida. It was primarily used for baseball, and was the home field of the Miami Marlins minor league baseball team, as well as other minor le ...
had a similar roof over the spectator area.
The largest cantilevered roof in Europe is located at
St James' Park
St James' Park is a football stadium in Newcastle upon Tyne, England. It is the home of Premier League club Newcastle United F.C. With a seating capacity of 52,305 seats, it is the eighth largest football stadium in England.
St James' Park ...
in
Newcastle-Upon-Tyne
Newcastle upon Tyne ( RP: , ), or simply Newcastle, is a city and metropolitan borough in Tyne and Wear, England. The city is located on the River Tyne's northern bank and forms the largest part of the Tyneside built-up area. Newcastle is als ...
, the home stadium of
Newcastle United F.C.
Newcastle United Football Club is an English professional football club, based in Newcastle upon Tyne, that plays in the Premier League – the top flight of English football. The club was founded in 1892 by the merger of Newcastle East End ...
[IStructE The Structural Engineer Volume 77/No 21, 2 November 1999. James's Park a redevelopment challenge][The Architects' Journal](_blank)
Existing stadiums: St James' Park, Newcastle. 1 July 2005
Less obvious examples of cantilevers are free-standing (vertical)
radio towers without
guy-wire
A guy-wire, guy-line, guy-rope, or stay, also called simply a guy, is a tensioned cable designed to add stability to a free-standing structure. They are used commonly for ship masts, radio masts, wind turbines, utility poles, and tents. A thi ...
s, and
chimneys
A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, stove, furnace, incinerator, or fireplace from human living areas. Chimneys are typic ...
, which resist being blown over by the wind through cantilever action at their base.
Image:ForthBridgeEdinburgh.jpg, The Forth Bridge
The Forth Bridge is a cantilever railway bridge across the Firth of Forth in the east of Scotland, west of central Edinburgh. Completed in 1890, it is considered a symbol of Scotland (having been voted Scotland's greatest man-made wonder in ...
, a cantilever truss bridge
Image:Pierre Pflimlin Bridge UC Adjusted.jpg, This concrete bridge
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...
temporarily functions as a set of two balanced cantilevers during construction – with further cantilevers jutting out to support formwork
Formwork is Molding (process), molds into which concrete or similar materials are either precast concrete, precast or cast-in-place concrete, cast-in-place. In the context of concrete construction, the falsework supports the shuttering mold ...
.
File:Howrah Bridge.jpg, Howrah Bridge
The Howrah Bridge is a balanced cantilever bridge over the Hooghly River in West Bengal. Commissioned in 1943, the bridge was originally named the New Howrah Bridge, because it replaced a pontoon bridge at the same location linking the cities ...
in India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, a cantilever bridge
Image:FallingwaterCantilever570320cv.jpg, A cantilevered balcony of the Fallingwater
Fallingwater is a house designed by the architect Frank Lloyd Wright in 1935 in the Laurel Highlands of southwest Pennsylvania, about southeast of Pittsburgh in the United States. It is built partly over a waterfall on Bear Run in the Mill R ...
house, by Frank Lloyd Wright
Frank Lloyd Wright (June 8, 1867 – April 9, 1959) was an American architect, designer, writer, and educator. He designed more than 1,000 structures over a creative period of 70 years. Wright played a key role in the architectural movements o ...
File:Canton Viaduct, Southern view, west side.JPG, A cantilevered railroad deck and fence on the Canton Viaduct
Canton Viaduct is a blind arcade cavity wall railroad viaduct in Canton, Massachusetts, built in 1834–35 for the Boston and Providence Railroad (B&P).
At its completion, it was the longest () and tallest () railroad viaduct in the world; toda ...
File:Cantilever-barn-moa-tn1.jpg, A cantilever barn in rural Tennessee
Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...
File:18-22-186-cades.jpg, Cantilever barn at Cades Cove
Cades Cove is an isolated valley located in the Tennessee section of the Great Smoky Mountains National Park. The valley was home to numerous settlers before the formation of the national park. Today Cades Cove, the single most popular destinati ...
File:DoubleJettiedBuilding.jpg, A double jettied building in Cambridge, England
File:Cantilever Jenga.JPG, Cantilever occurring in the game "Jenga
Jenga is a game of physical skill created by British board game designer and author Leslie Scott and marketed by Hasbro. Players take turns removing one block at a time from a tower constructed of 54 blocks. Each block removed is then placed on t ...
"
File:Riverplace Tower in Jacksonville.jpg, Cantilever facade of Riverplace Tower
The Riverplace Tower is a 28-floor office building on the south bank of the St. Johns River in Jacksonville, Florida. At the time of its construction, it was the tallest building in the state of Florida and was the defining landmark in Jacksonvi ...
in Jacksonville, Florida
Jacksonville is a city located on the Atlantic coast of northeast Florida, the most populous city proper in the state and is the largest city by area in the contiguous United States as of 2020. It is the seat of Duval County, with which the ...
, by Welton Becket
Welton David Becket (August 8, 1902 – January 16, 1969) was an American modern architect who designed many buildings in Los Angeles, California.
Biography
Becket was born in Seattle, Washington and graduated from the University of Washingt ...
and KBJ Architects
KBJ Architects, Inc. (KBJ) is an American architectural firm based in Jacksonville, Florida. The firm designed 17 of the city's 30 tallest buildings and "created Jacksonville's modern skyline", according to ''The Florida Times-Union'' newspaper.Ker ...
File:Cantilever crown.png, This radiograph
Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeut ...
of a "bridge" dental restoration features a cantilevered crown to the left.
File:Ronan Point collapse closeup.jpg, Ronan Point
Ronan Point was a 22-storey tower block in Canning Town in Newham, East London, that partly collapsed on 16 May 1968, only two months after it had opened. A gas explosion blew out some load-bearing walls, causing the collapse of one entire cor ...
: Structural failure of part of floors cantilevered from a central shaft.
Aircraft
![Junkers J 1 at Döberitz 1915](https://upload.wikimedia.org/wikipedia/commons/d/db/Junkers_J_1_at_D%C3%B6beritz_1915.jpg)
The cantilever is commonly used in the wings of
fixed-wing aircraft
A fixed-wing aircraft is a heavier-than-air flying machine, such as an airplane, which is capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are distinc ...
. Early aircraft had light structures which were braced with
wires and
strut
A strut is a structural component commonly found in engineering, aeronautics, architecture and anatomy. Struts generally work by resisting longitudinal compression, but they may also serve in tension.
Human anatomy
Part of the functionality o ...
s. However, these introduced aerodynamic drag which limited performance. While it is heavier, the cantilever avoids this issue and allows the plane to fly faster.
Hugo Junkers
Hugo Junkers (3 February 1859 – 3 February 1935) was a German aircraft engineer and aircraft designer who pioneered the design of all-metal airplanes and flying wings. His company, Junkers Flugzeug- und Motorenwerke AG (Junkers Aircraft and Mo ...
pioneered the cantilever wing in 1915. Only a dozen years after the
Wright Brothers' initial flights, Junkers endeavored to eliminate virtually all major external bracing members in order to decrease airframe drag in flight. The result of this endeavor was the
Junkers J 1
The Junkers J 1, nicknamed the ''Blechesel'' ("Tin Donkey" or "Sheet Metal Donkey"), was an experimental monoplane aircraft developed by Junkers & Co. It was the world's first all-metal aircraft.
Manufactured early on in the First World War, ...
pioneering all-metal monoplane of late 1915, designed from the start with all-metal cantilever wing panels. About a year after the initial success of the Junkers J 1,
Reinhold Platz
Reinhold Platz (16 January 1886 – 15 September 1966) was a German aircraft designer and manufacturer in service of the Dutch company Fokker.
Platz was hired by Fokker in 1912 as a welder. His first hands-on projects were to weld the frame pa ...
of
Fokker
Fokker was a Dutch aircraft manufacturer named after its founder, Anthony Fokker. The company operated under several different names. It was founded in 1912 in Berlin, Germany, and became famous for its fighter aircraft in World War I. In 1919 ...
also achieved success with a cantilever-winged
sesquiplane
A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a ...
built instead with wooden materials, the
Fokker V.1.
![De Havilland DH88 Comet](https://upload.wikimedia.org/wikipedia/commons/9/94/De_Havilland_DH88_Comet.jpg)
In the cantilever wing, one or more strong beams, called ''
spars
The United States Coast Guard (USCG) Women's Reserve, also known as the SPARS (SPARS was the acronym for "Semper Paratus—Always Ready"), was the women's branch of the United States Coast Guard Reserve. It was established by the United States ...
'', run along the span of the wing. The end fixed rigidly to the central fuselage is known as the root and the far end as the tip. In flight, the wings generate
lift
Lift or LIFT may refer to:
Physical devices
* Elevator, or lift, a device used for raising and lowering people or goods
** Paternoster lift, a type of lift using a continuous chain of cars which do not stop
** Patient lift, or Hoyer lift, mobile ...
and the spars carry this load through to the fuselage.
To resist horizontal shear stress from either drag or engine thrust, the wing must also form a stiff cantilever in the horizontal plane. A single-spar design will usually be fitted with a second smaller drag-spar nearer the
trailing edge
The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...
, braced to the main spar via additional internal members or a stressed skin. The wing must also resist twisting forces, achieved by cross-bracing or otherwise stiffening the main structure.
Cantilever wings require much stronger and heavier spars than would otherwise be needed in a wire-braced design. However, as the speed of the aircraft increases, the drag of the bracing increases sharply, while the wing structure must be strengthened, typically by increasing the strength of the spars and the thickness of the skinning. At speeds of around the drag of the bracing becomes excessive and the wing strong enough to be made a cantilever without excess weight penalty. Increases in engine power through the late 1920s and early 1930s raised speeds through this zone and by the late 1930s cantilever wings had almost wholly superseded braced ones. Other changes such as enclosed cockpits, retractable undercarriage, landing flaps and stressed-skin construction furthered the design revolution, with the pivotal moment widely acknowledged to be the
MacRobertson England-Australia air race of 1934, which was won by a
de Havilland DH.88 Comet
The de Havilland DH.88 Comet is a British two-seat, twin-engined aircraft built by the de Havilland Aircraft Company. It was developed specifically to participate in the 1934 England-Australia MacRobertson Air Race from the United Kingdom to A ...
.
Currently, cantilever wings are almost universal with bracing only being used for some slower aircraft where a lighter weight is prioritized over speed, such as in the
ultralight
Ultralight aviation (called microlight aviation in some countries) is the flying of lightweight, 1- or 2-seat fixed-wing aircraft. Some countries differentiate between weight-shift control and conventional three-axis control aircraft with ailer ...
class.
In microelectromechanical systems
Cantilevered beams are the most ubiquitous structures in the field of
microelectromechanical systems
Microelectromechanical systems (MEMS), also written as micro-electro-mechanical systems (or microelectronic and microelectromechanical systems) and the related micromechatronics and microsystems constitute the technology of microscopic devices, ...
(MEMS). An early example of a MEMS cantilever is the Resonistor, an electromechanical monolithic resonator. MEMS cantilevers are commonly fabricated from
silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic tab ...
(Si),
silicon nitride
Silicon nitride is a chemical compound of the elements silicon and nitrogen. is the most thermodynamically stable and commercially important of the silicon nitrides, and the term "silicon nitride" commonly refers to this specific composition. It ...
(Si
3N
4), or
polymer
A polymer (; Greek '' poly-'', "many" + ''-mer'', "part")
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
s.
The fabrication process typically involves undercutting the cantilever structure to ''release'' it, often with an anisotropic wet or
dry etching technique. Without cantilever transducers,
atomic force microscopy
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the op ...
would not be possible.
A large number of research groups are attempting to develop cantilever arrays as
biosensor
A biosensor is an analytical device, used for the detection of a chemical substance, that combines a biological component with a physicochemical detector.
The ''sensitive biological element'', e.g. tissue, microorganisms, organelles, cell recep ...
s for medical diagnostic applications. MEMS cantilevers are also finding application as
radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upp ...
filters
Filter, filtering or filters may refer to:
Science and technology
Computing
* Filter (higher-order function), in functional programming
* Filter (software), a computer program to process a data stream
* Filter (video), a software component tha ...
and
resonator
A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a resonator ...
s.
The MEMS cantilevers are commonly made as
unimorph
A unimorph or monomorph is a cantilever that consists of one active layer and one inactive layer.http://robotics.eecs.berkeley.edu/~ronf/PAPERS/icra01b.pdf In the case where active layer is piezoelectric, deformation in that layer may be induced ...
s or
bimorph
A bimorph is a cantilever used for actuation or sensing which consists of two active layers. It can also have a passive layer between the two active layers. In contrast, a piezoelectric unimorph has only one active (i.e. piezoelectric) layer and o ...
s.
Two equations are key to understanding the behavior of MEMS cantilevers.
The first is ''Stoney's formula'', which relates cantilever end
deflection
Deflection or deflexion may refer to:
Board games
* Deflection (chess), a tactic that forces an opposing chess piece to leave a square
* Khet (game), formerly ''Deflexion'', an Egyptian-themed chess-like game using lasers
Mechanics
* Deflection ...
δ to applied stress σ:
:
where
is
Poisson's ratio
In materials science and solid mechanics, Poisson's ratio \nu ( nu) is a measure of the Poisson effect, the deformation (expansion or contraction) of a material in directions perpendicular to the specific direction of loading. The value of Pois ...
,
is
Young's modulus
Young's modulus E, the Young modulus, or the modulus of elasticity in tension or compression (i.e., negative tension), is a mechanical property that measures the tensile or compressive stiffness of a solid material when the force is applied leng ...
,
is the beam length and
is the cantilever thickness. Very sensitive optical and capacitive methods have been developed to measure changes in the static deflection of cantilever beams used in dc-coupled sensors.
The second is the formula relating the cantilever
spring constant
In physics, Hooke's law is an empirical law which states that the force () needed to extend or compress a spring (device), spring by some distance () Proportionality (mathematics)#Direct_proportionality, scales linearly with respect to that ...
to the cantilever dimensions and material constants:
:
where
is force and
is the cantilever width. The spring constant is related to the cantilever resonance frequency
by the usual
harmonic oscillator
In classical mechanics, a harmonic oscillator is a system that, when displaced from its Mechanical equilibrium, equilibrium position, experiences a restoring force ''F'' Proportionality (mathematics), proportional to the displacement ''x'':
\v ...
formula
. A change in the force applied to a cantilever can shift the resonance frequency.
The frequency shift can be measured with exquisite accuracy using
heterodyne
A heterodyne is a signal frequency that is created by combining or mixing two other frequencies using a signal processing technique called ''heterodyning'', which was invented by Canadian inventor-engineer Reginald Fessenden. Heterodyning is us ...
techniques and is the basis of ac-coupled cantilever sensors.
The principal advantage of MEMS cantilevers is their cheapness and ease of fabrication in large arrays.
The challenge for their practical application lies in the square and cubic dependences of cantilever performance specifications on dimensions.
These superlinear dependences mean that cantilevers are quite sensitive to variation in process parameters, particularly the thickness as this is generally difficult to accurately measure. However, it has been shown that microcantilever thicknesses can be precisely measured and that this variation can be quantified. Controlling
residual stress
In materials science and solid mechanics, residual stresses are Stress (physics), stresses that remain in a solid material after the original cause of the stresses has been removed. Residual stress may be desirable or undesirable. For example, l ...
can also be difficult.
Chemical sensor applications
A
chemical sensor can be obtained by coating a recognition receptor layer over the upper side of a microcantilever beam. A typical application is the immunosensor based on an
antibody
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
layer that interacts selectively with a particular
immunogen
An immunogen is any substance that generates B-cell (humoral/antibody) and/or T-cell (cellular) adaptive immune responses upon exposure to a host organism.
Immunogens that generate antibodies are called antigens ("antibody-generating"). Immunogen ...
and reports about its content in a specimen. In the static mode of operation, the sensor response is represented by the beam bending with respect to a reference microcantilever. Alternatively, microcantilever sensors can be operated in the dynamic mode. In this case, the beam vibrates at its resonance frequency and a variation in this parameter indicates the concentration of the
analyte
An analyte, component (in clinical chemistry), or chemical species is a substance or chemical constituent that is of interest in an analytical procedure. The purest substances are referred to as analytes, such as 24 karat gold, NaCl, water, etc. ...
. Recently, microcantilevers have been fabricated that are porous, allowing for a much larger surface area for
analyte
An analyte, component (in clinical chemistry), or chemical species is a substance or chemical constituent that is of interest in an analytical procedure. The purest substances are referred to as analytes, such as 24 karat gold, NaCl, water, etc. ...
to bind to, increasing sensitivity by raising the ratio of the analyte mass to the device mass.
Surface stress on microcantilever, due to receptor-target binding, which produces cantilever deflection can be analyzed using optical methods like laser interferometry. Zhao et al., also showed that by changing the attachment protocol of the receptor on the microcantilever surface, the sensitivity can be further improved when the surface stress generated on the microcantilever is taken as the sensor signal.
[Yue Zhao,Agnivo Gosai, Pranav Shrotriya : Effect of Receptor Attachment on Sensitivity of Label Free Microcantilever Based Biosensor Using Malachite Green Aptamer https://doi.org/10.1016/j.snb.2019.126963]
See also
*
Applied mechanics
Applied mechanics is the branch of science concerned with the motion of any substance that can be experienced or perceived by humans without the help of instruments. In short, when mechanics concepts surpass being theoretical and are applied and e ...
*
Cantilever bicycle brakes
*
Cantilever bicycle frame
*
Cantilever chair
A cantilever chair is a chair whose seating and framework are not supported by the typical arrangement of 4 legs, but instead is held erect and aloft by a single leg or legs that are attached to one end of a chair's seat and bent in an L shape, thu ...
*
Cantilever method
The cantilever method is an approximate method for calculating shear forces and moment (physics), moments developed in beam (structure), beams and columns of a structural system, frame or structure due to lateral loads. The applied lateral loads t ...
*
Cantilevered stairs
Cantilevered stairs, or floating stairs, are a type of staircase.
A cantilever is a Beam (structure), beam, which is anchored at only one end. Thus cantilevered stairs have a "floating" appearance, and they may be composed of different materials, ...
*
Corbel arch
A corbel arch (or corbeled / corbelled arch) is an arch-like construction method that uses the architectural technique of corbeling to span a space or void in a structure, such as an entranceway in a wall or as the span of a bridge. A corbel v ...
*
Euler–Bernoulli beam theory
Euler–Bernoulli beam theory (also known as engineer's beam theory or classical beam theory) is a simplification of the linear theory of elasticity which provides a means of calculating the load-carrying and deflection characteristics of beams. ...
*
Grand Canyon Skywalk
The Grand Canyon Skywalk is a horseshoe-shaped cantilever bridge with a glass walkway at Eagle Point in Arizona near the Colorado River on the edge of a side canyon in the Grand Canyon West area of the main canyon.Yost, Mark.Close to the Edge ''W ...
*
Knudsen force
Knudsen force is the force experienced by two Surface, surfaces at two different Temperature, temperatures that are separated by a distance comparable to a mean free path of the Molecule, molecules of the ambient medium.
References
...
in the context of microcantilevers
*
Orthodontics
Orthodontics is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, and misaligned bite patterns. It may also address the modification of facial growth, known as dentofacial ...
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Statics
Statics is the branch of classical mechanics that is concerned with the analysis of force and torque (also called moment) acting on physical systems that do not experience an acceleration (''a''=0), but rather, are in static equilibrium with ...
References
Sources
* Inglis, Simon: ''Football Grounds of Britain''. CollinsWillow, 1996. page 206.
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Architectural elements
Structural system
Bridge components