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In the study of mechanisms, a four-bar linkage, also called a four-bar, is the simplest closed-chain movable linkage. It consists of four bodies, called bars or links, connected in a loop by four joints. Generally, the joints are configured so the links move in parallel planes, and the assembly is called a planar four-bar linkage. Spherical and ...
These links are usually oriented 180 degrees of each other, so when pairing, these links can be fused. This creates a 4-bar linkage with two additional links, both of which are defined by the original four-bar linkage. The former ground link of the fusing 4-bar linkage becomes a rectilinear link that travels follows the same coupler curve.
They can provide greater power transmission with more design flexibility than four-bar linkages. Jansen's linkage is an eight-bar leg mechanism that was invented by kinetic sculptor Theo Jansen. Klann linkage is a six-bar linkage that forms a leg mechanism; Toggle mechanisms are four-bar linkages that are dimensioned so that they can fold and lock.
[4] [5] [6] A generalized model of the flow distribution in channel networks of planar fuel cells. [6] Similar to Ohm's law, the pressure drop is assumed to be proportional to the flow rates. The relationship of pressure drop, flow rate and flow resistance is described as Q 2 = ∆P/R. f = 64/Re for laminar flow where Re is the Reynolds number.
Point 3 labels the transition from isentropic to Fanno flow. Points 4 and 5 give the pre- and post-shock wave conditions, and point E is the exit from the duct. Figure 4 The H-S diagram is depicted for the conditions of Figure 3. Entropy is constant for isentropic flow, so the conditions at point 1 move down vertically to point 3.
This can be used to calculate mean values (expectations) of the flow rates, head losses or any other variables of interest in the pipe network. This analysis has been extended using a reduced-parameter entropic formulation, which ensures consistency of the analysis regardless of the graphical representation of the network. [ 3 ]
The Hopkinson pressure bar was first suggested by Bertram Hopkinson in 1914 [1] as a way to measure stress pulse propagation in a metal bar. Later, in 1949 Herbert Kolsky [2] refined Hopkinson's technique by using two Hopkinson bars in series, now known as the split-Hopkinson bar, to measure stress and strain, incorporating advancements in the cathode ray oscilloscope in conjunction with ...
The exception in this list is Watt's parallel motion, which combines Watt's linkage with another four-bar linkage – the pantograph – to amplify the existing approximate straight line movement. It is not possible to create perfectly straight line motion using a four-bar linkage, without using a prismatic joint. Watt's linkage (1784)