2016-17


HYBRID STUMP CUTTER

Spencer Fynaardt, Adam Howerzyl, Josh Van Gorp, Austin Ver Meer

Stump cutters are used to remove tree stumps from the ground after the tree has been cut down. Current Vermeer stump cutters utilize a diesel engine to pump hydraulic oil to a hydraulic motor. This hydraulic motor turns the cutting wheel used to remove the stump. Hydraulic systems have inherent energy losses due to inefficiencies in the pump and motor, as well as friction in the hoses. Furthermore, the diesel engine must run at a fairly high speed to power the hydraulic system, which results in a noisy environment and high fuel consumption. Vermeer tasked us with investigating the possibility of replacing the current hydraulic system with a hybrid electric system.

We designed an electric system with fewer inefficiencies than the current hydraulic system, allowing more energy to be transferred from the fuel to the cutter wheel. Additionally, in the design of our hybrid system, the diesel engine can run at a lower speed, reducing noise and fuel consumption. We determined an appropriate system architecture and selected an alternating-current permanent magnet motor for our application. Finally, we performed an economic analysis to determine the efficiency and fuel cost savings of our hybrid electric system. Vermeer will be able use this information to continue their development of hybrid electric systems and to perform tests to see if electric systems can effectively cut wood.

 


STEMM SOLAR POWERED WATER PUMP

Ryan Christensen, Sean Quinlan, Nick Vander Kooi

Siouxland Tanzania Educational Medical Ministries (STEMM) founded an orphanage in 1996 near Arusha, Tanzania in response to an outbreak of AIDS. Currently, they continue to provide medical treatment to the area, house about 30 orphans, and grow food on their 100-acre plot of land. They want to expand their agricultural operations in order to raise and sell cash crops to help make the compound financially self-sustaining. There are two main problems preventing STEMM from accomplishing this goal: drought and electrical unreliability. There are four months out of the year where the area can go up to a month without rain and the electrical grid suffers periodic black outs. These two problems were responsible for a failed harvest a few years ago because their electric well pump was damaged due to electrical issues. STEMM needs a reliable irrigation system that will address these problems.

To meet their need, our team gathered information about their current well’s depth and maximum flow capacity. We also analyzed solar data to determine the feasibility of a solar powered pump. We then calculated water production, which allowed us to estimate the maximum drip tape irrigated acreage. Our final design was a solar-powered irrigation system capable of watering four acres using 21 polycrystalline Suntech solar panels and a PS4000 Lorentz controller/pump system.


AIR COMPRESSOR DESIGN

Michael Grady, Jacob Moats

Civco Radiotheropy manufactures a Vac-LockTM bag system that hospitals use to position patients in the same orientation during a sequence of cancer radiation treatments. The product requires the creation of a patient-specific mold, which uses a vacuum pump to remove air from the patient’s foam “cushion.” Civco would like to redesign the pump they currently use by making it lighter, cheaper, and safer.

The initial stage of our project required characterization of the current pump. This allowed us to create the standards and reasonable assumptions to facilitate a comparison for our design. Then, we designed and built a prototype pump. Our final design was a 5.4 pound pump and DC motor assembly that cost $265 (all major improvements on the previous design). However, the prototype did not perform as well in volumetric flow or peak pressure tests, so our client will need to make several adjustments to our prototype to increase its efficiency. 


SEED SORTING BY AERODYNAMICS

Mark Brauning, Andrew Cammenga, Daniel Lucht

The Land Institute (TLI) is a non-profit organization that researches and breeds new grain and seed crops that can be farmed in polycultures, mimicking a natural prairie-like system. The Institute is currently studying Silphium Perfoliatum, or Cup Plant, because of its potential as an oil crop (similar to oilseed sunflowers) that would be drought resistant. As part of this project, the research team needs to select for seeds that will separate well from the chaff during harvest with a combine. TLI request a device to assist in the aerodynamic characterization process.

We created an aerodynamic property analyzer (APA) to sort the seeds from a single silphium plant based on their aerodynamic properties. We used an iterative design method to test the multiple parts of the APA singly and in combination. In our final design, a batch of seeds from a silphium plant are dropped one at a time into a cross-breeze that blows along the table so that they eventually land in sorting bins that run the length of the table. An LED sensor counts the seed as it falls into the bin, generating a probability distribution model, which allows us to describe the plant’s characteristics numerically. A vacuum returns the sorted seeds back to the bench top for the operator. The APA decreases the time needed to evaluate the aerodynamics of seed batches while automating the testing.


WIND TUNNEL DRAG MODULE

Kolter Bradshaw, Mark Comfort, Timothy Rohda

The Dordt College Engineering Department has a wind tunnel that has primarily been used to demonstrate pressure-related phenomena such as pitot tubes. Professor Ethan Brue wants to expand the teaching capability of the tunnel by adding a module that can be integrated into the current tunnel to allow students to measure drag force on different shapes and visualize air flow.

We designed two different ways to measure drag using the existing wind tunnel. The primary drag measurement method, the Mechanical Module, utilizes a lever arm with adjustable counterweights to allow students to precisely measure drag in a simple and intuitive manner. The second method, the Strain Module, uses strain gauges in conjunction with a LabVIEW program to measure drag-created deflections electronically. Both methods measure strains with less than 10% accuracy, though the Strain Module is more accurate at lower speeds while the Mechanical maintains its accuracy over the full range of wind speeds.


BRIDGE LOAD INDICATOR

Hyun Myeong Goo, Cheong Hun Kim, Sam Van Bruggen

Providing tools for students to physically manipulate an object and observe how it responds is a powerful learning tool. The Dordt College Engineering department desires an interactive model that will allow students to apply loads to the members of a truss bridge and observe how this affects the stresses and strains in the members of the truss.

Our goal was to improve the design of a bridge that was originally created as part of a senior design project in 2014-15, by making it more reliable and easy to use. The original bridge used aluminum truss members instrumented with strain gages. LED lights along the members changed color based on the strain gage reading to indicate whether the bridge was in tension or compression. We machined slots in the original truss members so that they experienced a greater deflection (and strain) for the applied load. We also re-designed the electronics that linked the display LEDs and the strain gage sensors so that they functioned more reliably.


STRUCTURES BASED TEACHING SCULPTURE

Kelli Johnston, Jake Thayer, Breanna Veltkamp

Civil engineering projects often use large steel members with specific types of connections between the members. A sculpture can be used to help students visualize the different members and connections as opposed to viewing images on paper. A sculpture creates a realistic reference for different types of connections, members, and load situations that are common in construction.

We designed a sculpture that doubles as a student learning tool and an art piece. The sculpture was originally designed to be 10 feet tall and placed outdoors on the campus. Due to ongoing campus construction, installation of the full sculpture was not possible this spring, so instead we built a scale model that is roughly four feet tall, three feet wide at the base, and is mounted on casters to allow it to be easily transported from classroom to classroom. The sculpture consists of W-Shape I beams, channels, square tubes, and angles of various sizes and a steel cable. Both sculptures were analyzed extensively for safety, particularly the overturning moment (tipping). We also created homework problems using the sculpture are a reference.


HUMAN CARDIOVASCULAR MODEL

Rebekah De Penning, Stephanie Pausma, Eric Rowe, Josh Susman

The Dordt College Nursing Department needs a mechanical model of the circulatory system to help the nursing students make connections between physiological changes and clinical measurements. The model should allow students to see both normal and abnormal physiological conditions. Abnormal physiological conditions should include hypertension (high blood pressure) and partial artery occlusion (blood clots).

To meet this need we designed a physical model that mimics the heart pumping blood around the body by using a siphon-pump bulb to pump water through two closed loops of quarter-inch inner diameter tubing. Pressure and flow were measured using sensors and a LabVIEW interface at specific locations around the model. Interchangeable tubing allowed us to use different materials to simulate stages of atherosclerosis (hardening of the artery walls) which is one cause of hypertension. Flow control orifices with different inner diameters modeled different severities of partial occlusion. Preliminary testing of the systems separately showed that increasing tube hardness correlating with increasing fluid pressure, and that introducing occlusions measurably decreased flow and increased pressure. Future work should enhance the model by integrating both test systems into a single physical model for the circulatory system.


SPIKE FORCE 3.0

Chad DeGraaf, Boone DeKramer, Dylan Schmitz, Glen Thompson

Four years ago, the Dordt College volleyball coach, Chad Hanson, expressed concerns about players coming into the program with pre-existing shoulder injuries. He and engineering professor Dr. Kayt Frisch hypothesized that these injuries may result from overuse of the shoulder, particularly in in overhead motions (spike or serve). In order to understand possible causes, and eventually develop techniques for prevention and rehabilitation, they want to understand the biomechanics in the shoulder during a hit, and they need a method to measure the load due to contact during volleyball player’s hit.

We developed two solutions for measuring the hit on the hand. First, we estimated the contact force indirectly using a classical impulse-momentum analysis of 3D position data taken in the motion capture lab. We will present this method at the 2017 American Society of Biomechanics Annual Meeting (conference poster). Second, we developed a circuit that directly measures the force using sensors adhered to the hand. This was accomplished through three Arduino Microcontrollers that read and write data from variable resistor load sensors.