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Elastic torsion

Description:

A frame is a bent beam with rigid corners which creates a so-called structure gauge. This means that it spans a gap while at the same time creating height. This experimental unit  includes a typical U-shaped frame, such as is used in the construction of halls for example. One end is clamped into place, while the other can be loosely mounted. When the nonclamped end remains free, the statically determinate frame is investigated. A roller bearing on the non-clamped end creates a statically indeterminate frame. The frame is placed under load by weights. The load application points are movable. Two dial gauges record the deformations of the frame under load. By applying various methods (first-order elasticity theory; the principle of superposition; and the principle of virtual work), the bending moment characteristics are ascertained for a statically determinate and indeterminate frame. From these characteristic curves and a chart for integrals (coupling table) the differential equation of the bend line is formulated. From the bend line and its derivations, displacements and the support force on the movable support can be calculated. A second, S-shaped frame can be used to show that the various methods are applicable to any kind of frame. All the component elements of the experiment are clearly laid-out and housed securely in a storage system.

Learning Objective:

- Relationship between load application and deformation on the frame

- Differences between statically determinate and statically indeterminate frames

- familiarization with the first-order elasticity theory for statically determinate and indeterminate systems

- Application of the principle of superposition

- Application of the principle of virtual work on statically determinate and statically indeterminate frames

• determination of a deformation by the principle of virtual forces
• determination of a load by the principle of virtual displacement

- comparison of calculated and measured deformations

Device component:

Aluminum frame

S-shaped and U-shaped frames

Weights

Roller bearing

Movable hook

Plastic Torsion

Description:

The torsion test is a destructive testing method that studies the plastic behaviour of materials. In practice, components that are twisted in their application (e.g. screws, shafts, axles, wires and springs) are studied with this test method. This experimental unit allows torsion tests in which specimens are subjected to load until they fracture. The clean layout and simple operation mean the experimental sequence can be observed in all details and phases. In the experiment, metallic specimens are twisted until they are destroyed by a typical shear fracture. The twisting moment is applied manually by means of a handwheel and a worm gear. The base plate is torsionally reinforced. A transparent protective cover protects against flying fragments. The effective twisting moment is measured by means of a moment-measuring shaft fitted with strain gauges and can be read directly on a display. The twisting angle is recorded by an incremental encoder and can also be read. The measured values are transmitted directly to a PC where they can be analysed using the software. Specimens of different materials and different lengths are included in the scope of delivery. The measuring device can be moved on the rigid frame to adapt to different specimen lengths.Learning Objective:

Relationship between load and deflection for beams loaded to the plastic condition

Introduction to form factor

Introduction to limit state design

Relationship between maximum loading and plastic hinge formation for a simply supported beam, a propped cantilever and a fixed beam

Device component:

Aluminum frame

Fixed and roller support

Loadcell

Beams

Deformation of frames

Description:

A frame is a bent beam with rigid corners which creates a so-called structure gauge. This means that it spans a gap while at the same time creating height. This experimental unit  includes a typical U-shaped frame, such as is used in the construction of halls for example. One end is clamped into place, while the other can be loosely mounted. When the nonclamped end remains free, the statically determinate frame is investigated. A roller bearing on the non-clamped end creates a statically indeterminate frame. The frame is placed under load by weights. The load application points are movable. Two dial gauges record the deformations of the frame under load. By applying various methods (first-order elasticity theory; the principle of superposition; and the principle of virtual work), the bending moment characteristics are ascertained for a statically determinate and indeterminate frame. From these characteristic curves and a chart for integrals (coupling table) the differential equation of the bend line is formulated. From the bend line and its derivations, displacements and the support force on the movable support can be calculated. A second, S-shaped frame can be used to show that the various methods are applicable to any kind of frame. All the component elements of the experiment are clearly laid-out and housed securely in a storage system.

Learning Objective:

- Relationship between load application and deformation on the frame

- Differences between statically determinate and statically indeterminate frames

- familiarization with the first-order elasticity theory for statically determinate and indeterminate systems

- Application of the principle of superposition

- Application of the principle of virtual work on statically determinate and statically indeterminate frames

• determination of a deformation by the principle of virtual forces
• determination of a load by the principle of virtual displacement

- comparison of calculated and measured deformations

Device component:

Aluminum frame

S-shaped and U-shaped frames

Weights

Roller bearing

Movable hook