Torque density is a measure of the torque-carrying capability of a mechanical component. It is the ratio of torque capability to volume and is expressed in units of torque per volume. Torque density is a system property since it depends on the design of each element of the component being examined and their interconnection.
Property, in the abstract, is what belongs to or with something, whether as an attribute or as a component of said thing. In the context of this article, it is one or more components, whether physical or incorporeal, of a person's estate; or so belonging to, as in being owned by, a person or jointly a group of people or a legal entity like a corporation or even a society. Depending on the nature of the property, an owner of property has the right to consume, alter, share, redefine, rent, mortgage, pawn, sell, exchange, transfer, give away or destroy it, or to exclude others from doing these things, as well as to perhaps abandon it; whereas regardless of the nature of the property, the owner thereof has the right to properly use it, or at the very least exclusively keep it.
Torque density is useful during the concept evaluation stage of mechanical designs, especially in power train design problems. Typically, it will be one of many factors used to assign potential success measures to each concept. For example, in the upgrade of a drive train for a set of rolls in a rolling mill, space is often dictated by the configuration of current components. There may be several types of devices that can perform the function of an existing component that must be replaced. The relative torque densities of the devices may be an important determinant for which design is ultimately selected, although it will often compete with other factors such as cost, ease of maintenance, time to install, operating costs and potential failure modes.
Concepts are mental representations, abstract objects or abilities that make up the fundamental building blocks of thoughts and beliefs. They play an important role in all aspects of cognition.
Design can have different connotations in different fields of application, but there are two basic meanings of design: as a verb and as a noun.
Units
In SI units, torque density is expressed in joules per cubic metre or equivalently newton-metres per cubic metre (though dimensionally equivalent to the pascal, that is usually not used for this purpose). Small amounts can be expressed in newton-millimetres per cubic millimetre.
The joule is a derived unit of energy in the International System of Units. It is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre. It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889).
The cubic metre or cubic meter is the SI derived unit of volume. Its SI symbol is m3. It is the volume of a cube with edges one metre in length. An alternative name, which allowed a different usage with metric prefixes, was the stère, still sometimes used for dry measure. Another alternative name, no longer widely used, was the kilolitre.
The newton is the International System of Units (SI) derived unit of force. It is named after Isaac Newton in recognition of his work on classical mechanics, specifically Newton's second law of motion.
The inch is a unit of length in the (British) imperial and United States customary systems of measurement. It is equal to 1⁄36 yard or 1⁄12 of a foot. Derived from the Roman uncia ("twelfth"), the word inch is also sometimes used to translate similar units in other measurement systems, usually understood as deriving from the width of the human thumb. Standards for the exact length of an inch have varied in the past, but since the adoption of the international yard during the 1950s and 1960s it has been based on the metric system and defined as exactly 25.4mm.
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Related Research Articles
The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ, although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume:
Horsepower (hp) is a unit of measurement of power, or the rate at which work is done. There are many different standards and types of horsepower. Two common definitions being used today are the mechanical horsepower, which is about 745.7 watts, and the metric horsepower, which is approximately 735.5 watts.
The litre or liter is an SI accepted metric system unit of volume equal to 1 cubic decimetre (dm3), 1,000 cubic centimetres (cm3) or 1/1,000 cubic metre. A cubic decimetre occupies a volume of 10 cm×10 cm×10 cm and is thus equal to one-thousandth of a cubic metre.
Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure is the pressure relative to the ambient pressure.
In physics, power is the rate of doing work or of transferring heat, i.e. the amount of energy transferred or converted per unit time. Having no direction, it is a scalar quantity. In the International System of Units, the unit of power is the joule per second (J/s), known as the watt in honour of James Watt, the eighteenth-century developer of the condenser steam engine. Another common and traditional measure is horsepower. Being the rate of work, the equation for power can be written:
Torque, moment, or moment of force is the rotational equivalent of linear force. The concept originated with the studies of Archimedes on the usage of levers. Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object. The symbol for torque is typically
, the lowercase Greek letter tau. When being referred to as moment of force, it is commonly denoted by M.
United States customary units are a system of measurements commonly used in the United States. The United States customary system developed from English units which were in use in the British Empire before the U.S. became an independent country. However, the United Kingdom's system of measures was overhauled in 1824 to create the imperial system, changing the definitions of some units. Therefore, while many U.S. units are essentially similar to their Imperial counterparts, there are significant differences between the systems.
The metric system is an internationally recognised decimalised system of measurement. It is in widespread use, and where it is adopted, it is the only or most common system of weights and measures. It is now known as the International System of Units (SI). It is used to measure everyday things such as the mass of a sack of flour, the height of a person, the speed of a car, and the volume of fuel in its tank. It is also used in science, industry and trade.
The newton metre is a unit of torque in the SI system. One newton metre is equal to the torque resulting from a force of one newton applied perpendicularly to the end of a moment arm that is one metre long.
The cubic foot is an imperial and US customary (non-metric) unit of volume, used in the United States, and partially in Canada, and the United Kingdom. It is defined as the volume of a cube with sides of one foot (0.3048 m) in length. Its volume is 28.3168 liters or about 1⁄35 of a cubic meter.
The foot pound-force is a unit of work or energy in the Engineering and Gravitational Systems in United States customary and imperial units of measure. It is the energy transferred upon applying a force of one pound-force (lbf) through a linear displacement of one foot. The corresponding SI unit is the joule.
A barrel is one of several units of volume applied in various contexts; there are dry barrels, fluid barrels, oil barrels and so on. For historical reasons the volumes of some barrel units are roughly double the volumes of others; volumes in common usage range from about 100 to 200 litres. In many connections the term "drum" is used almost interchangeably with "barrel".
Both the imperial and United States customary systems of measurement derive from earlier English systems used in the Middle Ages, that were the result of a combination of the local Anglo-Saxon units inherited from German tribes and Roman units brought by William the Conqueror after the Norman Conquest of England in 1066.
Dimensional weight, also known as volumetric weight, is a pricing technique for commercial freight transport, which uses an estimated weight that is calculated from the length, width and height of a package.
A pound-foot (lbf⋅ft) is a unit of torque. One pound-foot is the torque created by one pound of force acting at a perpendicular distance of one foot from a pivot point. Conversely one pound-foot is the moment about an axis that applies one pound-force at a radius of one foot.
A coherent system of units is a system of units based on a system of quantities in such a way that the equations between the numerical values expressed in the units of the system have exactly the same form, including numerical factors, as the corresponding equations between the quantities. Equivalently, it is a system in which every quantity has a unique unit, or one that does not use conversion factors.
The imperial system of measurement and the US customary system of measurement are both derived from an earlier English system of measurement which in turn can be traced back to Ancient Roman units of measurement, and Carolingian and Saxon units of measure.
The klafter is an historical unit of length, volume and area that was used in Central Europe.
