The Griffith equation is used to calculate the approximate amount of critical stress necessary to propagate a crack. The formula for the equation is K = √(πE/2Y), where E is Young's modulus, and Y is the geometrical factor, which depends on the shape of the crack.
The equation is based on the energy release rate for crack propagation and was developed by A.A. Griffith in 1921. The equation is used to calculate the stress intensity factor (K) for a crack in an elastic material.
The Griffith equation is important for engineers as it can be used to estimate how much stress a material can withstand before it will fracture. This is important when designing components or structures that will be subject to loading or fatigue. Additionally, the equation can be used to calculate the stress concentration factor (Kt) at a point of crack initiation.
In conclusion, the Griffith equation is an important equation used to calculate the approximate amount of critical stress necessary to propagate a crack. This equation can be used by engineers to ensure that their designs are able to withstand the expected loads, as well as calculate stress concentration factors.
You can learn more about Griffith at: brainly.com/question/30188283
#SPJ11
a 1,200a feeder is tapped (over 10ft but less than 25 ft long)to supply a 225a main breaker panelboard having a 180a continuous load. what's the minimum size thhn copper feeder tap conductor that can be used?
The correct answer is To determine the minimum size of the THHN copper feeder tap conductor, we need to calculate the ampacity of the tap conductor based on the 75-degree Celsius column of the NEC table 310.16.
First, we need to find the equivalent ampacity of the 225A main breaker panelboard. Since it is a continuous load, we have to multiply it by 1.25. So, 225A x 1.25 = 281.25A. Next, we need to find the percentage of the feeder ampacity required for the tap conductor. The NEC table 310.16 allows tap conductors to have an ampacity not less than one-third of the rating of the overcurrent device protecting the feeder. Therefore, 1200A/3 = 400A. Finally, we can calculate the minimum size THHN copper feeder tap conductor using the following formula: Minimum conductor ampacity = (281.25A - 180A) + 180A = 281.25A Minimum conductor ampacity = 281.25A / 0.8 (derating factor) = 351.56A From the NEC table 310.16, the minimum size THHN copper conductor with an ampacity of 351.56A is 2/0 AWG. Therefore, the minimum size THHN copper feeder tap conductor that can be used is 2/0 AWG.
To learn more about minimum size click on the link below:
brainly.com/question/29727023
#SPJ1
A 40 HP motor with a load factor of 75% and an efficiency of 89.3% will be replaced with a 30 HP motor with a load factor of 100% and an efficiency of 93.6%. How many kW of power savings will be obtained from this project?
First, we need to calculate the actual power consumption of the 40 HP motor with a load factor of 75% and an efficiency of 89.3%.
Actual power consumption = Rated power x Load factor / Efficiency
= 40 HP x 0.75 / 0.893
= 33.6 kW
Next, we need to calculate the actual power consumption of the 30 HP motor with a load factor of 100% and an efficiency of 93.6%.
Actual power consumption = Rated power x Load factor / Efficiency
= 30 HP x 1 / 0.936
= 31.9 kW
The power savings from this project can be calculated as the difference between the actual power consumption of the 40 HP motor and the actual power consumption of the 30 HP motor.
Power savings = Actual power consumption of 40 HP motor - Actual power consumption of 30 HP motor
= 33.6 kW - 31.9 kW
= 1.7 kW
Therefore, the project will result in a power savings of 1.7 kW.
The Mississippi River is on average 20 ft deep and considered one of the widest rivers in the world at around one mile. It is mud-lined with a Manning's roughness coefficient of 0.03. Using a fake slope of 0.0006, what is the river's velocity in ft/s?
Using a fake slοpe οf 0.0006, The Mississippi River mοves at a speed οf rοughly 10.13 feet per secοnd.
The Mississippi River's brοadest pοint is where?The Mississippi River is brοader than 11 miles in Lake Winnibigοshish, which is clοse tο Bena, Minnesοta. The Mississippi shipping rοute's widest navigable part, Lake Pepin, has a channel width οf arοund twο miles.
Q = (1/n) × A × (R²/³) × S¹/²
Tο sοlve fοr velοcity :
V = Q / A
A = depth * width = 20 ft × 5280 ft
= 105,600 ft²
R = A / P
where P is the wetted perimeter οf the channel, which is the length οf the bοundary between the water and the channel bed. Fοr a rectangular channel,
P = 2 × depth + width
= 2 × 20 ft + 5280 ft
= 5320 ft
R = 105,600 ft² / 5320 ft
= 19.81 ft
Nοw we can plug in the values intο the Manning's equatiοn:
Q = (1/0.03) × 105600 ft² × (19.81 ft)²/³ × (0.0006)¹/²
= 1,069,301 ft³/s
Finally, we can calculate the velοcity:
V = Q /
= 1,069,301 ft³/s / 105,600 ft²
= 10.13 ft/s
Learn more about speed :
brainly.com/question/29780075
#SPJ1
building envelope, sometimes also called thermal envelope or building enclosure, controls the flows of between the interior and exterior of the building?
The building envelope is an essential component of any structure, providing a protective barrier between the interior and exterior of the building. By controlling the flow of air, moisture, and heat, the building envelope ensures the indoor air quality and energy efficiency of the building.
The components of the building envelope include the walls, roofs, windows, doors, and foundation of the building, as well as insulation and other materials. The primary purpose of the building envelope is to provide a protective barrier against the elements, ensuring the interior of the building is insulated from the outside climate. The building envelope also helps to maintain indoor air quality, as it reduces the amount of air infiltration from outside. In addition, the building envelope increases the efficiency of the building’s heating and cooling systems, reducing energy consumption and costs.
In order to maintain its protective barrier, the building envelope must be constructed with durable and weather-resistant materials. Additionally, the building envelope should be properly sealed to reduce air leakage. Windows and doors should be designed to minimize the risk of water infiltration, while insulation should be installed to reduce heat transfer.
You can learn more about building envelopes at: brainly.com/question/28163927
#SPJ11
Kelvin contact resistance test structure in Fig. P3. 19, it is usually assumed that the voltmeter has very high input resistance and there is negligible voltage drop along the voltage measurement arm
In the Kelvin contact resistance test structure in Fig. P3.19, it is usually assumed that the voltmeter has very high input resistance and there is negligible voltage drop along the voltage measurement arm.
This assumption is made because the purpose of the Kelvin contact resistance test is to measure the resistance of a contact without including the resistance of the contact leads.To achieve this, the current is passed through the current leads, and the voltage is measured using the voltage leads. However, if the voltage leads have any resistance, this will add to the measured resistance value, making it inaccurate. To avoid this, the Kelvin contact resistance test structure uses two sets of voltage leads, one to carry the current and another to measure the voltage, so that any resistance in the measurement leads is not included in the measured resistance value.By assuming that the voltmeter has very high input resistance and there is negligible voltage drop along the voltage measurement arm, the Kelvin contact resistance test structure ensures that any resistance in the measurement leads is insignificant compared to the resistance of the contact being measured. This allows for accurate measurement of contact resistance and is a common technique used in electrical testing.for more such question on voltage
https://brainly.com/question/1176850
#SPJ11
