Jared Leidich talks about what big, important projects take -- teamwork, communication and failure.
Students act as structural engineers and learn about forces and load distributions as they follow the steps of the engineering design process to design and build small-scale bridges using wooden tongue depressors and glue. Teams brainstorm ideas that meet the size and material design constraints and create prototype bridges of the most promising solutions. They test their bridges to see how much weight they can hold until they break and then determine which have the highest strength-to-weight ratios. They examine the prototype failures to identify future improvements. This activity is part of a unit in which multiple activities are brought together for an all-day school/multi-school concluding “engineering field day” competition.
Students take a close look at truss structures, the geometric shapes that compose them, and the many variations seen in bridge designs in use every day. Through a guided worksheet, students draw assorted 2D and 3D polygon shapes and think through their forms and interior angles (mental “testing”) before and after load conditions are applied. They see how engineers add structural members to polygon shapes to support them under compression and tension, and how triangles provide the strongest elemental shape. A PowerPoint® presentation is provided. This lesson prepares students for two associated activities that continue the series on polygons and trusses.
Students learn about the role engineers play in designing and building truss structures. Simulating a real-world civil engineering challenge, student teams are tasked to create strong and unique truss structures for a local bridge. They design to address project constraints, including the requirement to incorporate three different polygon shapes, and follow the steps of the engineering design process. They use hot glue and Popsicle sticks to create their small-size bridge prototypes. After compressive load tests, they evaluate their results and redesign for improvement. They collect, graph and analyze before/after measurements of interior angles to investigate shape deformation. A PowerPoint® presentation, design worksheet and data collection sheet are provided. This activity is the final step in a series on polygons and trusses.
This course covers interpretations of the concept of probability. Topics include basic probability rules; random variables and distribution functions; functions of random variables; and applications to quality control and the reliability assessment of mechanical/electrical components, as well as simple structures and redundant systems. The course also considers elements of statistics; Bayesian methods in engineering; methods for reliability and risk assessment of complex systems (event-tree and fault-tree analysis, common-cause failures, human reliability models); uncertainty propagation in complex systems (Monte Carlo methods, Latin Hypercube Sampling); and an introduction to Markov models. Examples and applications are drawn from nuclear and other industries, waste repositories, and mechanical systems.
Over several days, students learn about composites, including carbon-fiber-reinforced polymers, and their applications in modern life. This prepares students to be able to put data from an associated statistical analysis activity into context as they conduct meticulous statistical analyses to evaluate/determine the effectiveness of carbon fiber patches to repair steel. This lesson and its associated activity are suitable for use during the last six weeks of an AP Statistics course; see the topics and timing note for details. A PowerPoint® presentation and post-quiz are provided.
Risk analysis, assessment, and management is essential to any engineering field. This course is designed to provide students with an understanding of how to perform a comprehensive risk assessment applicable to a wide variety of engineering problems. The course will focus on failure mode and effect analysis, fault tree analysis, probabilistic risk analysis, and human reliability analysis. The course will also cover fundamental probability and statistics content.
Students learn about probability through a LEGO® MINDSTORMS® NTX-based activity that simulates a game of "rock-paper-scissors." The LEGO robot mimics the outcome of random game scenarios in order to help students gain a better understanding of events that follow real-life random phenomenon, such as bridge failures, weather forecasts and automobile accidents. Students learn to connect keywords such as certainty, probable, unlikely and impossibility to real-world engineering applications.
Students investigate the critical nature of foundations as they learn differences between shallow and deep foundations, including the concepts of bearing pressure and settlement. Using models representing a shallow foundation and a deep pile foundation, they test, see and feel the effects in a cardboard box test bed composed of layers of pebbles, soil and sand. They also make bearing pressure calculations and recommendations for which type of foundations to use in various engineering scenarios.
Civil engineers design structures such as buildings, dams, highways and bridges. Student teams explore the field of engineering by making bridges using spaghetti as their primary building material. Then they test their bridges to see how much weight they can carry before breaking.
Students learn about the strength of bones and methods of helping to mend fractured bones. During a class demonstration, a chicken bone is broken by applying a load until it reaches a point of failure (fracture). Then, working as biomedical engineers, students teams design their own splint or cast to help repair a fractured bone, learning about the strength of materials used.
This course introduces analysis techniques for complex structures and the role of material properties in structural design, failure, and longevity. Students will learn about the energy principles in structural analysis and their applications to statically-indeterminate structures and solid continua. Additionally, the course will examine matrix and finite-element methods of structured analysis including bars, beams, and two-dimensional plane stress elements. Structural materials and their properties will be considered, as will metals and composites. Other topics include modes of structural failure, criteria for yielding and fracture, crack formation and fracture mechanics, and fatigue and design for longevity. Students are expected to apply these concepts to their own structural design projects.
Students conduct several simple lab activities to learn about the five fundamental load types that can act on structures: tension, compression, shear, bending, and torsion. To learn the telltale marks of failure caused by these load types, they break foam insulation blocks by applying these five load types, carefully examine each type of fracture pattern (break in the material) and make drawings of the fracture patterns.
Students build model caverns and bury them in a tray of sand. They test the models by dropping balls onto them to simulate an asteroid hitting the Earth. By molding papier-mache or clay around balloons (to form domes), or around small cardboard boxes (to form rectangular structures), students create unique models of their cavern designs.
Students learn about regular polygons and the common characteristics of regular polygons. They relate their mathematical knowledge of these shapes to the presence of these shapes in the human-made structures around us, especially trusses. Through a guided worksheet and teamwork, students explore the idea of dividing regular polygons into triangles, calculating the sums of angles in polygons using triangles, and identifying angles in shapes using protractors. They derive equations 1) for the sum of interior angles in a regular polygon, and 2) to find the measure of each angle in a regular n-gon. This activity extends students’ knowledge to engineering design and truss construction. This activity is the middle step in a series on polygons and trusses, and prepares students for the Polygon and Popsicle Trusses associated activity.
Students work within constraints to construct model trusses and then test them to failure as a way to evaluate the relative strength of different truss configurations and construction styles. Each student group uses Popsicle sticks and hot glue to build a different truss configuration from a provided diagram of truss styles. Within each group, each student builds two exact copies of the team's truss configuration using his/her own construction method, one of which is tested under shear conditions and the other tested under compression conditions. Results are compiled and reviewed as a class to analyze the strength of different types of shapes and construction methods under the two types of loads. Students make and review predictions, and normalize strengths. Teams give brief presentations to recap their decisions, results and analysis.
What makes rockets fly straight? What makes rockets fly far? Why use water to make the rocket fly? Students are challenged to design and build rockets from two-liter plastic soda bottles that travel as far and straight as possible or stay aloft as long as possible. Guided by the steps of the engineering design process, students first watch a video that shows rocket launch failures and then participate in three teacher-led mini-activities with demos to explore key rocket design concepts: center of drag, center of mass, and momentum and impulse. Then the class tests four combinations of propellants (air, water) and center of mass (weight added fore or aft) to see how these variables affect rocket distance and hang time. From what they learn, student pairs create their own rockets from plastic bottles with cardboard fins and their choices of propellant and center of mass placement, which they test and refine before a culminating engineering field day competition. Teams design for maximum distance or hang time; adding a parachute is optional. Students learn that engineering failures during design and testing are just steps along the way to success.