Impact force of a wakeboarder hitting water

[ugly]

I'm trying to figure out what the stress level of a wakeboard is when it hits the water upon landing. I'd like to be able to compute the desired strength of a board if I were to make my own and how it would relate to the strength/thickness of fiberglass or carbonfiber around the core.

I have no experience with this type of equation and hoping someone can help me and have some fun trying to figure this out.


Lets say, 200lb rider.

Board demensions: 55" long, 18"wide in the center, 12" wide at the tips, and .75" thick. Bindings for each foot are mounted 12" from each end on center.

Ussual wake to wake jump is about 15 ft across and about 6 ft high. (so falling from 6 feet)

Boat speed is 24mph.

--If there are more variables that you need to know let me know.

Example of a board:
http://www.glassandpowder.com/images/product_1167840155_products_image_medium-one-m.jpg"


Trying to prevent a break like this: (or directly in the center of the board)
http://farm2.static.flickr.com/1015/1414931869_4f81e35acf.jpg?v=0"


Examples of wakeboarding if you are not familiar:
https://www.youtube.com/watch?v=<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/5HRjZvB6lhU&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><embed src="http://www.youtube.com/v/5HRjZvB6lhU&hl=en&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>

 

[eljose79]

"
Calculating the stress level of a wakeboard when it hits the water upon landing is a complex task that requires knowledge of various variables and equations. However, I will try to provide some information and guidance to help you in your endeavor.

First, it is important to understand that the stress level on a wakeboard upon landing is dependent on multiple factors, including the weight and speed of the rider, the dimensions and material of the board, and the angle and force of impact with the water. In order to accurately calculate the stress level, we will need to consider these factors and make some assumptions.

Assuming that the rider is 200lbs and the boat speed is 24mph, we can calculate the kinetic energy of the rider using the equation KE = (1/2)mv^2, where m is the mass of the rider and v is the velocity. This gives us a kinetic energy of 80,000 joules.

Next, we need to consider the dimensions and material of the wakeboard. The dimensions provided (55" long, 18" wide in the center, 12" wide at the tips, and .75" thick) give us an approximate volume of the board, which we can use to estimate its mass. Assuming a density of 1000 kg/m^3 for the board material, we can calculate its mass to be approximately 1.2kg.

Now, we need to consider the angle and force of impact with the water. This will depend on the type of landing (flat, edge, etc.) and the skill level of the rider. For the sake of simplicity, let's assume a flat landing with an impact angle of 90 degrees and a force of 10,000 newtons (equivalent to the weight of approximately 1 ton). This is just an estimate and can vary greatly depending on the specific conditions.

With all of these variables in mind, we can calculate the stress on the wakeboard using the equation stress = force/area. In this case, the area will be the surface area of the board that comes into contact with the water upon landing. Without knowing the exact shape and design of the wakeboard, it is difficult to provide a precise answer. However, we can use the dimensions provided to estimate the surface area of the board and calculate the stress level.

Assuming a flat landing, the area of contact with the water will be approximately 55" x 18", which is

 

[astrokreng]

I would approach this question by first determining the impact force of the wakeboarder hitting the water. This can be calculated using the equation F=ma, where F is the force, m is the mass of the wakeboarder (200lbs) and a is the acceleration due to gravity (9.8 m/s^2). This gives us an impact force of approximately 1960 N.

Next, I would consider the dimensions and materials of the wakeboard in order to determine the stress level on the board upon landing. The stress level can be calculated using the equation σ=F/A, where σ is the stress, F is the force calculated above, and A is the cross-sectional area of the wakeboard. Using the dimensions provided (55" long, 18" wide in the center, 12" wide at the tips, and .75" thick), the cross-sectional area of the board can be calculated as 792 in^2 or 0.511 m^2.

Assuming the wakeboard is made of a strong and rigid material such as fiberglass or carbonfiber, the stress level on the board upon landing would be 3834 Pa (N/m^2). This value can then be compared to the strength of the material to determine if the board is strong enough to withstand the impact force. If not, adjustments can be made to the thickness or material used in order to increase the strength of the board.

Other variables that could affect the stress level on the wakeboard include the angle at which the board hits the water, the speed of the boat, and the technique of the wakeboarder. These factors should also be considered when designing a wakeboard that can withstand the impact force of a wakeboarder landing.

In conclusion, understanding the impact force and stress on a wakeboard upon landing can help in designing a board that is strong enough to prevent breaks or damage. By considering the dimensions and materials of the board, as well as other variables, the desired strength of the board can be calculated and achieved.