Model Description This is a simple demonstration of the basic principles and behavior underlying stress concentrations. Stresses at points of load application can be much larger than the average stress in a member. The same is true when a member contains a discontinuity. Paper members with the same mid-span width are used to demonstrate the […]
Model Description This simple demonstration depicts how moments (and forces) result in bending of a beam and how the deformation is related to the assumptions associated with elastic beam behavior. A foam beam with vertical lines (black lines) and a horizontal line drawn along the neutral axis (red line) for a rectangular beam is used […]
Model Description This is a simple demonstration of the basic principles underlying the elastic and plastic behavior of materials subjected to an axial load. The demonstration can also be used to show the highlight the elastic and plastic portions of stress-strain curves. This demonstration should take 8-10 minutes. Engineering Principle The basic definitions for stress, […]
Model Description This is a simple demonstration to introduce the basic principles of experimentation, analysis, and design in reference to axially loaded members. Copper wire is used to lift an object of known weight. In order to determine the minimum number of copper wire strands required to lift the load, students perform experiments, analysis, and […]
Model Description This is a simple demonstration of the basic principles underlying the behavior of materials subjected to an axial load. The demonstration can also be used to show the usefulness of stress-strain curves versus load-deformation curves. This demonstration should take 10 minutes. Engineering Principle The basic definitions for deformation and strain: where the axial […]
Model Description A thin rectangular sheet of rubber material is subject to an axial load. Stress blocks are painted or drawn on the rubber material. The stress blocks are oriented on a transverse plane (black square) and on a plane 45° from the transverse plane (red square). Students have previously learned that only normal stress […]
OVERVIEW This inquiry-based learning activity (IBLA) is completed by students in class before elastic bending theory is presented. PRINCIPLES By completing this scripted exercise, students are exposed to the varying strain profile through the depth of a beam. From this strain profile, students apply Hooke’s law to develop the stress profile, then calculate equivalent tension […]
OVERVIEW This exercise uses an engine hoist, an engine block, and an aluminum “dog bone” to measure the weight of the engine block. The dog bone has strain gages attached. With the measured strain, students calculate the associated weight. PRINCIPLES Reinforces the relationship between strain and stress; and between stress and force. This exercise also […]
Overview Thrill your students with Tales of Torque using the versatile Tower of Torque! In it’s simplest form, the device allows students to predict and then measure the capacity of a simple bolt, modeled as a rod in torsion. Principle For cylindrical rods in torsion, the maximum shear stress experienced is seen at the outer […]
Overview This is a simple demonstration of the basic principals underlying the behavior of thin-walled pressure vessels (TWPVs). A balloon or balloons are used to show that hoop stresses are twice as high as longitudinal stresses in cylindrical pressure vessels. Principle The basic derivation for TWPV behavior states that for a cylindrical pressure vessel […]