Mechanical Design Certification Service

Australian Standards require that equipment or structures be designed according to a specific standard. We at Dynamic Engineering makes this process as easy as possible for our clients by providing a design certification service. There are several different ways in accomplishing this, through physical testing of equipment and computer simulations, such as Finite Element Analysis.

Physical testing of equipment

In some instances, computer simulation cannot be used to certify a design. Then it is necessary to build a prototype and physical test the equipment, often to destruction. This approach is sometimes specified in the standard – for example for ROPS, FOPS and FUPS devices

 

Finite Element Analysis

Computer assisted stress analysis streamlines the certification of equipment. A 3d-computer model takes the guesswork out of new designs. Changes can be made quickly and inexpensively and the result can be checked straightaway. With Finite Element Analysis (FEA) different loads can be applied, including gravity, remote force and torque. The resultant stresses and deflection can be checked against design specifications.

 

Design certification is becoming more and more popular and in the case of some mining clients is now a requirement for all new equipment. Design certification can be achieved for both new and used equipment, provided certain information is known:

1) For new equipment the following is required:

• A drawing that fix the design (dimensions, materials and welding)
• Engineering calculations (require loads and load combinations)

2) For existing equipment

• A drawing that fix the design (dimensions, materials and welding). The equipment would therefore need to be measured up (in some cases dismantled)
• Engineering calculations (require loads and load combinations)
• Actual load test to confirm the design calculations and construction.

We can help with all of the above. By developing a 3D model of your equipment and applying the loads, we can produce a stress plot that can be used to prove the design or even to increase the reliability of the design. It is fast, cost effective and saves a lot of time and money associated with breakdowns – not to mention the safety risks associated with failures.

 

In some cases we are asked to give our opinion if certain maintenance activities would be safe. One such assignment was to check if a corroded tailing pipe could be lifted while in operation. Our analysis showed this to be a high risk activity and we advised our client against this – showing areas of concern as well as the behaviour of the model under certain load cases. With our model we were able to predict load versus deflection curves, as well as the required crane tonnage.

 

Although our analysis indicated that the lift should not take place, our client still received the benefit of avoiding a large clean-up bill and other associated incidents. Sometimes it really pays to check out the engineering aspects of a job before it is attempted.

Short description of FEA

The first step in computer modelling is drawing the equipment or tool in three dimensions. The CAD software then meshes the model by subdividing it into smaller elements. The loads and constraints are added and the resultant stresses and deflections are calculated for each of these numerous elements. Lastly stress and deflection equations are solved for each of these elements and the results are combined to find the overall solution. Below are some stress analysis examples showing the resultant stresses:

 

 

 

 

Finite element analysis can be applied to several different applications, such as Machine design, Maintenance tools and Civil/Structural design