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Weight Distribution
Weight distribution is the apportioning of weight within a vehicle, especially cars, airplanes, and trains. Typically, it is written in the form ''x''/''y'', where ''x'' is the percentage of weight in the front, and ''y'' is the percentage in the back. In a vehicle which relies on gravity in some way, weight distribution directly affects a variety of vehicle characteristics, including handling, acceleration, traction, and component life. For this reason weight distribution varies with the vehicle's intended usage. For example, a drag car maximizes traction at the rear axle while countering the reactionary pitch-up torque. It generates this counter-torque by placing a small amount of counterweight at a great distance forward of the rear axle. In the airline industry, load balancing is used to evenly distribute the weight of passengers, cargo, and fuel throughout an aircraft, so as to keep the aircraft's center of gravity close to its center of pressure to avoid losing pitch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weight
In science and engineering, the weight of an object is the force acting on the object due to gravity. Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar quantity, the magnitude of the gravitational force. Yet others define it as the magnitude of the reaction force exerted on a body by mechanisms that counteract the effects of gravity: the weight is the quantity that is measured by, for example, a spring scale. Thus, in a state of free fall, the weight would be zero. In this sense of weight, terrestrial objects can be weightless: ignoring air resistance, the famous apple falling from the tree, on its way to meet the ground near Isaac Newton, would be weightless. The unit of measurement for weight is that of force, which in the International System of Units (SI) is the newton. For example, an object with a mass of one kilogram has a weight of about 9.8 newtons on the surface of the Earth, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Surface Effect
The free surface effect is a mechanism which can cause a watercraft to become unstable and capsize. It refers to the tendency of liquids — and of unbound aggregates of small solid objects, like seeds, gravel, or crushed ore, whose behavior approximates that of liquids — to move in response to changes in the attitude of a craft's cargo holds, decks, or liquid tanks in reaction to operator-induced motions (or sea states caused by waves and wind acting upon the craft). When referring to the free surface effect, the condition of a tank that is not full is described as a "slack tank", while a full tank is "pressed up". Stability and equilibrium In a normally loaded vessel any rolling from perpendicular is countered by a righting moment generated from the increased volume of water displaced by the hull on the lowered side. This assumes the center of gravity of the vessel is relatively constant. If a moving mass inside the vessel moves in the direction of the roll, this counters th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerospace Engineering
Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is similar, but deals with the electronics side of aerospace engineering. "Aeronautical engineering" was the original term for the field. As flight technology advanced to include vehicles operating in outer space, the broader term "aerospace engineering" has come into use. Aerospace engineering, particularly the astronautics branch, is often colloquially referred to as "rocket science". Overview Flight vehicles are subjected to demanding conditions such as those caused by changes in atmospheric pressure and temperature, with structural loads applied upon vehicle components. Consequently, they are usually the products of various technological and engineering disciplines including aerodynamics, Air propulsion, avionics, materials science, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weight Transfer
Weight transfer and load transfer are two expressions used somewhat confusingly to describe two distinct effects: *the change in load borne by different wheels of even perfectly rigid vehicles during acceleration *the change in center of mass (CoM) location relative to the wheels because of suspension compliance or cargo shifting or sloshing In the automobile industry, weight transfer customarily refers to the change in load borne by different wheels during acceleration. This would be more properly referred to as load transfer, and that is the expression used in the motorcycle industry, while weight transfer on motorcycles, to a lesser extent on automobiles, and cargo movement on either is due to a change in the CoM location relative to the wheels. This article uses this latter pair of definitions. Load transfer In wheeled vehicles, load transfer is the measurable change of load borne by different wheels during acceleration (both longitudinal and lateral). This includes b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tilt Test (vehicle Safety Test)
The tilt test is a type of safety test that certain government vehicle certification bodies require new vehicle designs to pass before being allowed on the road or rail track. The test is an assessment of the weight distribution and hence the position of the centre of gravity of the vehicle, and can be carried out in a laden or unladen state, i.e. with or without passengers or freight. The test can be applied to automobiles, trucks, buses and rail vehicles. The test involves tilting the vehicle in the notional direction of the side of the vehicle, on a movable platform. In order to pass the test, the vehicle must not tip over before a specified angle of tilt is reached by the table. In the United Kingdom, double-decker bus A double-decker bus or double-deck bus is a bus that has two storeys or decks. They are used for mass transport in the United Kingdom, the United States, New Zealand, Europe, Asia and also in cities such as Sydney; the best-known example is the ...es have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roll Center
The roll center of a vehicle is the notional point at which the cornering forces in the suspension are reacted to the vehicle body. There are two definitions of roll center. The most commonly used is the geometric (or kinematic) roll center, whereas the Society of Automotive Engineers uses a force-based definition.An Introduction to Modern Vehicle Design edited by Julian Happian-Smith P293 Definition * Geometric roll center is solely dictated by the suspension geometry, and can be found using principles of the instant center of rotation. * Force based roll center, according to the US Society of Automotive Engineers, is "The point in the transverse vertical plane through any pair of wheel centers at which lateral forces may be applied to the sprung mass without producing suspension roll". The lateral location of the roll center is typically at the center-line of the vehicle when the suspension on the left and right sides of the car are mirror images of each other. The si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Distribution
In physics and mechanics, mass distribution is the spatial distribution of mass within a solid body. In principle, it is relevant also for gases or liquids, but on Earth their mass distribution is almost homogeneous. Astronomy In astronomy mass distribution has decisive influence on the development e.g. of nebulae, stars and planets. The mass distribution of a solid defines its center of gravity and influences its dynamical behaviour - e.g. the oscillations and eventual rotation. Mathematical modelling A mass distribution can be modeled as a measure. This allows point masses, line masses, surface masses, as well as masses given by a volume density function. Alternatively the latter can be generalized to a distribution. For example, a point mass is represented by a delta function defined in 3-dimensional space. A surface mass on a surface given by the equation may be represented by a density distribution , where g/\left, \nabla f\ is the mass per unit area. The mathematical m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Load Transfer
Weight transfer and load transfer are two expressions used somewhat confusingly to describe two distinct effects: *the change in load borne by different wheels of even perfectly rigid vehicles during acceleration *the change in center of mass (CoM) location relative to the wheels because of suspension compliance or cargo shifting or sloshing In the automobile industry, weight transfer customarily refers to the change in load borne by different wheels during acceleration. This would be more properly referred to as load transfer, and that is the expression used in the motorcycle industry, while weight transfer on motorcycles, to a lesser extent on automobiles, and cargo movement on either is due to a change in the CoM location relative to the wheels. This article uses this latter pair of definitions. Load transfer In wheeled vehicles, load transfer is the measurable change of load borne by different wheels during acceleration (both longitudinal and lateral). This includes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center Of Percussion
The center of percussion is the point on an extended massive object attached to a pivot where a perpendicular impact will produce no reactive shock at the pivot. Translational and rotational motions cancel at the pivot when an impulsive blow is struck at the center of percussion. The center of percussion is often discussed in the context of a bat, racquet, door, sword or other extended object held at one end. The same point is called the center of oscillation for the object suspended from the pivot as a pendulum, meaning that a simple pendulum with all its mass concentrated at that point will have the same period of oscillation as the compound pendulum. In sports, the center of percussion of a bat, racquet, or club is related to the so-called " sweet spot", but the latter is also related to vibrational bending of the object. Explanation Imagine a rigid beam suspended from a wire by a fixture that can slide freely along the wire at point P, as shown in the Figure. An impulsive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Center Of Mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may be applied to cause a linear acceleration without an angular acceleration. Calculations in mechanics are often simplified when formulated with respect to the center of mass. It is a hypothetical point where the entire mass of an object may be assumed to be concentrated to visualise its motion. In other words, the center of mass is the particle equivalent of a given object for application of Newton's laws of motion. In the case of a single rigid body, the center of mass is fixed in relation to the body, and if the body has uniform density, it will be located at the centroid. The center of mass may be located outside the physical body, as is sometimes the case for hollow or open-shaped objects, such as a horseshoe. In the case of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trucking Industry In The United States
The trucking industry serves the American economy by transporting large quantities of raw materials, works in process, and finished goods over land—typically from manufacturing plants to retail distribution centers. Trucks are also used in the construction industry, two of which require dump trucks and portable concrete mixers to move the large amounts of rocks, dirt, concrete, and other building materials used in construction. Trucks in America are responsible for the majority of freight movement over land and are tools in the manufacturing, transportation, and warehousing industries. Driving large trucks and buses require a commercial driver's license (CDL) to operate. Obtaining a CDL requires extra education and training dealing with the special knowledge requirements and handling characteristics of such a large vehicle. Drivers of commercial motor vehicles (CMVs) must adhere to the hours of service, which are regulations governing the driving hours of commercial drivers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loadmaster
A loadmaster is an aircrew member on civilian aircraft or military transport aircraft tasked with the safe loading, transport and unloading of aerial cargoes. Loadmasters serve in the militaries and civilian airlines of many nations. Duties The loadmaster performs the calculations and plans cargo and passenger placement to keep the aircraft within permissible center of gravity limits throughout the flight. Loadmasters ensure cargo is placed on the aircraft in such a way as to prevent overloading sensitive sections of the airframe and cargo floor. Considerations are also given to civilian and military regulations which may prohibit the placement of one type of cargo in proximity to another. Unusual cargo may require special equipment to be loaded safely aboard the aircraft, limiting where the other cargo may feasibly be placed. Tactically, loadmasters may also directly affect combat readiness as they are also responsible for determining the load order of aircraft so that mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
