Name: lifting tong force analysis
Uploaded: 2023-09-22T11:49:25.000Z
Duration: 1 min 30 s
Channel: JoVE

Prendi in considerazione una pinza di sollevamento che trasporta un carico di 100 kg. Comprende sezioni mobili DAF e CBG collegate tra loro con l'elemento AB.
Supponendo che la struttura sia simmetrica rispetto al punto E, quale forza agisce sull'asta AB?
Viene disegnato un diagramma a corpo libero che indica le forze agenti nel punto E.
La forza di trazione del cavo bilancia il peso del carico e agisce verticalmente verso l'alto.
ED e EC sono membri a due forze. Quindi, le forze FED e FEC sono dirette rispettivamente verso le articolazioni D e C.
Queste forze vengono risolte in componenti orizzontali e verticali e la geometria della struttura viene applicata per determinare l'angolo tra l'asta ED e la componente di forza orizzontale.
L'applicazione della condizione di equilibrio della forza lungo la direzione orizzontale garantisce che FED sia uguale a FEC.
Allo stesso modo, la condizione di equilibrio della forza verticale produce la forza lungo l'asta ED.
A questo punto, si consideri un diagramma a corpo libero per la sezione DAF. La condizione di equilibrio del momento può essere applicata all'articolazione F. 
Sostituendo tutti i valori noti nell'equazione si ottiene la forza lungo l'asta AB.

<ol>
	<li>Hibbeler, R.C. (2016). Ingegneria Meccanica \u2012 Statica e Dinamica. Hoboken, New Jersey: Pearson Prentice HallPppp 305.</li>
	<li>Birra, F.P.; Johnston, E.R.; Mazurek, D.F; Cromwell, P.J. e Self, B.P. (2019). Meccanica vettoriale per ingegneri \u2012 Statica e dinamica. New York: McGraw-Hill. pagine 348</li>
	<li>Meriam, JL, Kraige, LG e Bolton, JN (2020). Ingegneria Meccanica \u2012 Statica. Hoboken, New Jersey: John Wiley. pagine 200</li>
</ol>

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macchine: risoluzione dei problemi ii

Le macchine sono complesse strutture composte da elementi mobili connessi tra loro, che lavorano insieme per trasmettere forze. Considera una pinza da sollevamento che tiene un carico di 100 kg. È composta da sezioni mobili DAF e CBG collegate tra di loro dall'elemento AB.

Assumendo che la struttura sia simmetrica nel punto E, è possibile calcolare la forza che agisce sull'elemento AB.

<img alt="Figure 1" src="/files/ftp_upload/14295/14295_PT_Fig_1v2.svg" style="text-align: center; height: 350px;" />

Prima di tutto, si considera un diagramma di corpo libero che indica le forze agenti sul punto E. Il peso del carico, che equivale alla massa moltiplicata per l'accelerazione di gravità, viene calcolato pari a 981 N. La forza di tensione del cavo bilancia il peso del carico e agisce verticalmente verso l'alto. ED ed EC sono elementi a due forze. Di conseguenza, le forze FED ed FECM sono dirette rispettivamente verso le giunzioni D e C.

Successivamente, le forze FED ed FEC vengono risolte in componenti orizzontali e verticali. La geometria della struttura può calcolare l'angolo tra l'elemento ED e la componente orizzontale della forza di 30,96 gradi.

Le condizioni di equilibrio delle forze possono essere applicate alla giunzione E.

<img alt="Equation 1" src="/files/ftp_upload/14295/14295_PT_Equation_1v2.svg" style="text-align: center; height: 13px;" />

<img alt="Equation 2" src="/files/ftp_upload/14295/14295_PT_Equation_2v2.svg" style="text-align: center; height: 13px;" />

Applicando la condizione di equilibrio delle forze lungo la direzione orizzontale, si ottiene che FED è uguale a FEC. Allo stesso modo, la condizione di equilibrio delle forze verticali fornisce la forza lungo l'elemento ED pari a 953,46 N.

Ora, si considera un diagramma di corpo libero per la sezione DAF. La condizione di equilibrio dei momenti può essere applicata alla giunzione F.

<img alt="Equation 3" src="/files/ftp_upload/14295/14295_PT_Equation_3v2.svg" style="text-align: center; height: 13px;" />

Il risultato fornisce la forza lungo l'elemento AB pari a 2423,76 N.

Comprendere le forze che agiscono su ciascun elemento in questo sistema della pinza da sollevamento, è essenziale per garantire un'operazione sicura e progettare meccanismi di sollevamento efficienti. Analizzando le forze e applicando le condizioni di equilibrio, gli ingegneri possono ottimizzare la struttura e assicurarsi che possa sollevare carichi in sicurezza in diverse condizioni.

Macchine: Risoluzione dei problemi II

Le macchine sono strutture complesse costituite da elementi multiforza mobili e collegati a perni che lavorano insieme per trasmettere le forze. Prendi in considerazione una pinza di sollevamento ...

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Machines: Problem Solving II

lifting tong force analysis

Lifting tong force analysis shows how forces move through a pin-connected machine. The structure uses movable sections DAF and CBG with member AB linking them together. Because these parts work as connected members, the load can be studied with equilibrium methods.

The example starts with a 100 kg load at point E. The load weight is found by multiplying mass by gravity, which gives 981 N. The cable tension acts upward and balances that weight. Since the structure is symmetrical at E, the forces on the two sides can be compared.

Members ED and EC are two-force members, so their forces act along the members toward joints D and C. Their forces are then split into horizontal and vertical parts. Using the geometry of the tong, the angle between member ED and the horizontal is 30.96 degrees. Force equilibrium at joint E shows that F ED equals F EC, and the vertical balance gives the force in member ED as 953.46 N.

After that, a free-body diagram for section DAF is used. The moment equilibrium condition is applied at joint F. This step gives the force in member AB as 2423.76 N. This kind of analysis helps engineers check the forces in each member so lifting systems can work safely and efficiently under load.

Lifting Tong Force Analysis

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machines: problem solving ii

Lifting tong force analysis shows how forces move through a pin-connected machine. The structure uses movable sections DAF and CBG with member AB linking them together. Because these parts work as connected members, the load can be studied with equilibrium methods. The example starts with a 100 kg load at point E. The load weight is found by multiplying mass by gravity, which gives 981 N. The cable tension acts upward and balances that weight. Since the structure is symmetrical at E, the...

key terms and concepts

Analyze a lifting tong with pin-connected members, symmetry, and equilibrium. See how force, tension, and moments determine the load on member AB.

Lifting Tong Force Analysis | JoVE K12

JoVE Core Mechanical Engineering offers concise, easy-to-understand animated videos covering key topics such as equilibrium, forces, truss analysis, and structural mechanics. Explore their real-world applications, and witness these concepts in action through scientist-led experiments.

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Lifting Tong Force Analysis

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