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Calc Mech

Mechanical Engineering Consulting

Analysis

Camera Housing – FEA

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FEA of Camera Housing for field hazard analysis. 

Will this enclosure protect a movie camera from damage if run over by a truck during filming?

A selection of case scenarios are analyzed using finite element analysis (FEA).

The maximum hoop stress for the cylindrical camera housing is hand calculated and benchmarked against the computed FEA results. 

This unique application simulated an anchored camera housing with external radial forces applied to observe the impact to the limiting material hoop stresses.

The related stresses were compared to postulated impact scenarios to establish a plausible outcome.

 

Heart Shield

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HeartShield Product

Heart Shield

This innovative product is mounted to the chest of an athletic youth player. This purpose of this product is to protect the youth if a direct hit from a ball hits the chest. Extensive in-depth analysis is performed to measure the impact forces and the amount experienced by the user.

The free-body diagram identifies the reaction force locations and the sensors are placed to measure the foot and mid-point reaction forces.

Shield Free Body Diagram    Advanced Oscilloscope and signal conditioning measurement equipment Sample oscilloscope dataDetailed data is collected from multiple impact conditions for multiple shield materials that characterize the behavior of the products and affects on the user. Enjoy the very brief video clip of one such data sample.

Dish Scoops

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Bending & Breaking ice cream dish scoops in various failure modes.

This fun project was creatively discovering the limitations of the product. How much handle torque (twist) before it breaks from the scoop region? How hard can you pull on the handle before separation? How strong is the bowl portion of the scoop? How much force is required to separate the plastic handle from the metal scoop? What failure mode does the gear exhibit under heavy load? This critical data is compared among multiple products and design revisions to objectively measure design improvement.

    

 

Boiling and coating durability testing

Severe environmental testing was conducted on the product coating of ice cream scoops. This innovative scoop also contains an internal heat transfer fluid where body heat is used to aid in the product’s application. Several scoop designs were exercised through extreme cold, hot, pressure, and common household chemicals to measure the long-term durability. An interesting test is attaching a hydraulic hose with a pressure gauge to the side of an ice cream scoop.


Deckboards

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Analysis of Deckboards for strength and environmental shade.

An innovative deckboard design is highly slotted of an environmentally friendly material is tested for strength and environmental impact to casting a shadow that affects the shade.

 The product is analyzed for bending from a simulated person standing in the worst-case center to evaluate the maximum stresses and deflection.

 

 

A second analysis is simulated for thermal expansion from extreme outdoor temperature conditions.

 

 

A third analysis is a simulated drop test to evaluate the stresses for general handling.

 

 

 

A fourth analysis calculates the illumination below the installed product for a various heights. There is not an acceptance criterion.

 

Antenna Enclosure

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Antenna Enclosure Design

A challenging customer unknown application required fitting a patch-array antenna inside a tightly fit radome. The mounting bracket and electrical connectors were specified. Determining a compact configuration that allows the application rotational mobility, installation, and manufacturability requires in-depth dimensional prototyping and attention to detail.

The above figure shows a summary of the large mounting bracket that attaches to the plate-like antenna region with the connectors on the side. The cut-away on the end shows the internal layers.

 

Wind Loading

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Two projects about wind loading:

  • Antenna wind loading
  • Advertising fin for car mounting

Antenna wind loading

This particularly challenging problem utilized newly designed and fabricated outdoor dipole antennas where the customer needed to know the wind loading capability of the new product.

 

The complex multi-layered construction of the antenna means that an alternate method is needed to establish the assembled material parameters. An innovative simply supported structure was created and measured weights were added at known locations. This gave the information needed (modulus of elasticity and moment of inertia) to measure the forces and bending displacement to characterize the various dipole antenna materials and construction.

As the wind blows, the antenna deflects, which reduces the amount of projected surface area. The reduction of the surface area reduces the applied force on the bending of the antenna. Additionally, the geometry drag coefficient changes based on the flow. The measured testing data was analyzed in a circular iteration formula to solve the fluid-structure relationship to establish the maximum wind loading and related bending forces for high storm conditions.

Advertising Car Fin

Car Fin

Constructed a custom wind tunnel and force pull testing to measure the attachment forces for the magnetic and adhesive connections. Using the data of measured structural attachment strength and wind tunnel aerodynamic drag, the maximum safe road speed is determined for various orientation and mounting methods.

Tennis Rackets

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This is a great testing and analysis project.

The manufacturer of tennis rackets created innovative (unknown) internal changes to their product. A series of four rackets were tested and uniquely characterized the behavior of each product.

Strain gages were mounted near the base of the handle (where a user would hold). The gages were connected using a half-bridge wheatstone circuit for conditioning and data measurement on an oscilloscope.

  

The fun begins as a tennis ball is dropped from measured heights (known potential energy for future calculations) to impact the tennis rackets and measure the response.

  

Using the collected data, further analysis is performed to characterize the unique qualities of each tennis racket for the responsiveness to the user. The damped natural frequency, damping ratio, and amount of absorbed energy information is provided to the customer that clearly characterized the behavior of each tennis racket design.