constraint

con·straint

C0591000 (kən-strānt′)n.1. The threat or use of force to prevent, restrict, or dictate the action or thought of others.2. The state of being restricted or confined within prescribed bounds: soon tired of the constraint of military life.3. One that restricts, limits, or regulates; a check: ignored all moral constraints in his pursuit of success.4. Embarrassed reserve or reticence; awkwardness: "All constraint had vanished between the two, and they began to talk" (Edith Wharton).

[Middle English constreinte, from Old French, from feminine past participle of constraindre, to constrain; see constrain.]

constraint

(kənˈstreɪnt) n1. compulsion, force, or restraint2. repression or control of natural feelings or impulses3. a forced unnatural manner; inhibition4. something that serves to constrain; restrictive condition: social constraints kept him silent. 5. (Grammar) linguistics any very general restriction on a sentence formation rule

con•straint

(kənˈstreɪnt)

n. 1. limitation or restriction. 2. repression of natural feelings and impulses. 3. unnatural restraint in manner; embarrassment. 4. something that constrains. 5. the act of constraining. 6. the condition of being constrained. [1350–1400; Middle English constreinte < Middle French, n. use of feminine past participle of constreindre; see constrain]

Thesaurus

Noun	1.	constraint - the state of being physically constrained; "dogs should be kept under restraint"restraintconfinement - the state of being confined; "he was held in confinement"cage - something that restricts freedom as a cage restricts movement
	2.	constraint - a device that retards something's motion; "the car did not have proper restraints fitted"restraintair bag - a safety restraint in an automobile; the bag inflates on collision and prevents the driver or passenger from being thrown forwardairbrake, dive brake - a small parachute or articulated flap to reduce the speed of an aircraftarrester, arrester hook - a restraint that slows airplanes as they land on the flight deck of an aircraft carrierband - a restraint put around something to hold it togetherbrake - a restraint used to slow or stop a vehiclebrake - anything that slows or hinders a process; "she wan not ready to put the brakes on her life with a marriage"; "new legislation will put the brakes on spending"brake pad - one of the pads that apply friction to both sides of the brake diskbrake shoe, skid, shoe - a restraint provided when the brake linings are moved hydraulically against the brake drum to retard the wheel's rotationcatch, stop - a restraint that checks the motion of something; "he used a book as a stop to hold the door open"chain - anything that acts as a restraintdevice - an instrumentality invented for a particular purpose; "the device is small enough to wear on your wrist"; "a device intended to conserve water"fastening, holdfast, fastener, fixing - restraint that attaches to something or holds something in placegag, muzzle - restraint put into a person's mouth to prevent speaking or shoutingleash, tether, lead - restraint consisting of a rope (or light chain) used to restrain an animalignition lock, lock - a restraint incorporated into the ignition switch to prevent the use of a vehicle by persons who do not have the keymuzzle - a leather or wire restraint that fits over an animal's snout (especially a dog's nose and jaws) and prevents it from eating or bitinglife belt, safety belt, safety harness - belt attaching you to some object as a restraint in order to prevent you from getting hurtsea anchor, drogue - restraint consisting of a canvas covered frame that floats behind a vessel; prevents drifting or maintains the heading into a windhamper, shackle, trammel, bond - a restraint that confines or restricts freedom (especially something used to tie down or restrain a prisoner)trammel - a restraint that is used to teach a horse to amble
	3.	constraint - the act of constraining; the threat or use of force to control the thoughts or behavior of othersrestriction, confinement - the act of keeping something within specified bounds (by force if necessary); "the restriction of the infection to a focal area"swaddling clothes - restrictions placed on the immature

constraint

noun1. restriction, limitation, curb, rein, deterrent, hindrance, damper, check Their decision to abandon the trip was made because of financial constraints.2. force, pressure, necessity, restraint, compulsion, coercion People are not morally responsible for that which they do under constraint or compulsion.3. repression, reservation, embarrassment, restraint, inhibition, timidity, diffidence, bashfulness She feels no constraint in discussing sexual matters.

constraint

noun1. Power used to overcome resistance:coercion, compulsion, duress, force, pressure, strength, violence.2. The act of limiting or condition of being limited:circumscription, confinement, limitation, restraint, restriction.3. Something that limits or restricts:check, circumscription, cramp, curb, inhibition, limit, limitation, restraint, restriction, stricture, trammel.

Translations

Beschränkungassujettissementcontraintecostrizionebegrenzingbeperkinginperkingrandvoorwaardeзакрепощённость

constraint

Constraint

A restriction on the natural degrees of freedom of a system. If n and m are the numbers of the natural and actual degrees of freedom, the difference n - m is the number of constraints. In principle n = 3N, where N is the number of particles, for example, atoms. In practice n is determined by the number of effectively rigid components.

A holonomic system is one in which the n original coordinates can be expressed in terms of m independent coordinates and possibly also the time. It is characterized by frictionless contacts and inextensible linkages. The new coordinates are called generalized coordinates. See Lagrange's equations

Nonholonomic systems cannot be reduced to independent coordinates because the constraints are not on the n coordinate values themselves but on their possible changes. For example, an ice skate may point in all directions but at each position it must point along its path. See Degree of freedom (mechanics)

constraint

any restraining social influence which leads an individual to conform to social NORMS or social expectations.

For DURKHEIM, the distinctive SOCIAL FACTS, or sociological phenomena, that sociologists study can be recognized, above all, as ‘those ways of acting… capable of exercising an external constraint over the individual’. Durkheim recognized that such socially constraining forces may also be internalized by individuals, but it was an essential feature of his conception of such constraints that they had an origin external to the individual. Thus Durkheim's use of the term is much wider than the notion of ‘constraint’ in which the individual who wishes to act one way is made to act in another. As Lukes (1973) points out, Durkheim's use of the term ‘constraint’ at times suffers from considerable ambiguity failing to distinguish clearly between:

the authority of legal rules, customs, etc. as manifested by the sanctions brought to bear on violators of these;
the necessity of following rules to carry out certain activities successfully (e.g. the rules of language);
the ‘causal influence’ of ‘morphological factors’ such as the influence of established channels of communication or transportation on commerce or migration;
psychological compulsions in a crowd or social movement;
cultural determination and the influence of SOCIALIZATION.

However, Durkheim's overall intention is clear: to draw attention to the fact that distinctively social reality constrains, and is ‘external’ to the individual, in each and any of the above senses. See also COLLECTIVE CONSCIENCE, FREE WILL, DETERMINISM.

Constraint

(or reaction of a connection). For connections formed by bodies of any type, constraints are the forces of reaction of these bodies acting on points of the mechanical system. In contradistinction to active forces, constraints have values not known in advance. They depend not only on the type of connection but also on the active forces acting on the system; if the system is in motion, they depend additionally on how the system is moving. They are determined by solving the corresponding problems in mechanics. The directions of constraints or reactions in some cases are determined by the type of connection. Thus, if a point in the system is forced to remain always on a given smooth (frictionless) surface as a result of applied connections, then the reaction R is directed along the normal n

Figure 1. Examples of connections applied to a body P: (a) smooth surface, (b) smooth support, (c) inelastic flexible thread

to this surface (Figure 1). Figure 2 shows a smooth cylindrical hinge (bearing), for which two components (R_x and R_y) of the reaction are unknown, and a smooth ball and socket joint for which all three components (R_x, R_y, and R_z) of the reaction are unknown. For a rough surface, the constraint has two components: a normal and a tangential component; the latter is called the frictional force.

Figure 2. Examples of reactions with unknown components: (a) two unknown components, (b) three unknown components

In the general case, in solving problems in dynamics a restricted mechanical system is considered a free system if certain forces are applied to its points, such that the conditions imposed on the system by the connections are always satisfied when the system is in motion; these forces are called constraints.

S. M. TARG

Constraint

a restriction imposed on the position or motion of a mechanical system. Constraints are usually realized by bodies. Examples of constraints are a surface along which a body slides or rolls, a thread by which a weight is suspended, and joints connecting the links of mechanisms. If the positions of points of a mechanical system relative to a given reference system are determined by the points’ Cartesian coordinates x_k, y_k, z_k (k = 1, 2,…,n, where n is the number of points in the system), then the restrictions imposed by the constraints can be expressed in the form of equalities or inequalities that give the relation between the time t, the coordinates x_k, y_k, z_k, and the first derivatives of the coordinates with respect to time ẋ_k, ẏ_k, ż_k (that is, the velocities of the points of the system).

Constraints that impose restrictions only on the positions (coordinates) of the points of a system and are expressed by equations of the form

(1) f(…, x_k, y_k, z_k,…,t) = 0

are called geometric constraints. If the constraints also impose restrictions on the velocities of the points of the system, they are called kinematic constraints, and their equations are of the form

(2) Φ(…, x_k, y_k, z_k,…, ẋ_k, ẏ_k, ż_k,…,t) = 0

When equation (2) can be integrated with respect to time, the corresponding kinematic constraint is said to be integrable and is equivalent to a geometric constraint. Geometric and integrable kinematic constraints have the common name of holonomic constraints (seeHOLONOMIC SYSTEMS). Kinematic nonintegrable constraints are called nonholonomic (seeNONHOLONOMIC SYSTEMS).

Constraints that do not change with time are referred to as stationary constraints; their equations do not explicitly contain t. On the other hand, constraints that change with time are called moving constraints. Finally, two-way constraints are constraints such that to each virtual displacement of points of the system there corresponds a displacement in precisely the opposite direction. The equations of such constraints are of the form of equations (1) and (2). One-way constraints are constraints that do not satisfy the condition for two-way constraints. An example is a flexible thread, which permits displacement along the thread in only one direction. Such constraints are expressed by inequalities of the form f(…, x_k, y_k, z_k,…)≥0.

The methods of solving problems in mechanics depend to a substantial degree on the nature of the constraints on the system. The effect of the action of constraints can be taken into account by introducing corresponding forces, called constraint forces. To determine these forces (or to eliminate the forces), constraint equations of the form (1) or (2) must be added to the equations of equilibrium or motion of the system. Ideal constraints are constraints for which the sum of the elementary works of all the forces in any virtual displacement of the system is equal to zero. Examples are a frictionless surface or flexible thread. For mechanical systems with ideal constraints, it is possible to obtain immediately equations of equilibrium or of motion that do not contain constraint forces by using the virtual work principle, the d’Alembert-Lagrange principle, or the Lagrange equations.

S. M. TARG

constraint

[kən′strānt] (engineering) Anything that restricts the transverse contraction which normally occurs in a solid under longitudinal tension. (mechanics) A restriction on the natural degrees of freedom of a system; the number of constraints is the difference between the number of natural degrees of freedom and the number of actual degrees of freedom. (science and technology) A condition imposed on a system which limits the freedom of the system; may be physical or mathematical, necessary or incidental.

constraint

(programming, mathematics)A Boolean relation, often anequality or ineqality relation, between the values of one ormore mathematical variables (often two). E.g. x>3 is aconstraint on x. constraint satisfaction attempts to assignvalues to variables so that all constraints are true.

Usenet newsgroup: news:comp.constraints. FAQ.

constraint

con·straint

constraint

con•straint

constraint

constraint

constraint

Constraint

constraint

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constraint

Synonyms for constraint

noun restriction

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noun force

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noun repression

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Synonyms for constraint

noun power used to overcome resistance

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noun the act of limiting or condition of being limited

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noun something that limits or restricts

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Synonyms for constraint

noun the state of being physically constrained

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Related Words

noun a device that retards something's motion

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noun the act of constraining

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