At Dynamic Engineering we make this process as easy as possible for our clients by providing a design certification service. We specialise in Civil/Structural Design, Maintenance Tools and Lifting Equipment Design Certification. In addition Dynamic Engineering can also provide Independent Design Verification as required by the plant and design registration process.
Design Certification
There are several different ways in accomplishing certification: through physical testing of equipment, calculations and computer simulations. Computer assisted stress analysis (such as Finite Element Analysis) can be a cost-effective way of verifying designs of equipment or tools.
Calculations
We use the relevant Australian Standards like AS 4100, AS 3990 etc. to analyse structures, equipment or machinery to ensure design compliance. These calculations are typically summarised in a design report.
Finite Element Analysis
Computer assisted stress analysis streamlines the certification of equipment, because a 3D computer model takes the guesswork out of our client’s new designs. We can check the results straightaway and in addition make changes quickly and inexpensively. With Finite Element Analysis (FEA) we can apply several different loads including gravity, remote force and torque. Afterwards these resultant stresses and deflection can be checked against design specifications.
Below is a pit gearbox, which was modelled in 3D to determine its stresses.
Stresses in gearbox lifter
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 the information below is known:
1) For new equipment the following is required:
- A drawing that fixes the design (dimensions, materials and welding)
- Engineering calculations (require loads and load combinations)
2) For existing equipment
- A drawing that fixes the design (dimensions, materials and welding). The equipment would therefore need to be measured (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 our client’s equipment and applying the loads, we can produce stress plots to prove the design or even to increase its reliability. 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.
Typical stress plot produced for the design certification of the rig
Structural Modelling
Another method of analysis would be to model the structure in a program called Space Gass. This program utilises beam elements to analyse more complex structures in an economical way.
Space Gass model
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 Australian Standard – for example for ROPS, FOPS and FUPS devices.
It is important to understand that to certify a ROPS or FOPS structure, physical testing must be conducted, because calculations are not allowed in terms of the Australian Standard. To do this, our client would need a test rig and a sacrificial physical ROPS/FOPS structure. In most cases, to produce a test bed and destructively test a ROPS would be an expensive exercise. Therefore it only makes sense if larger quantities of these units were to be built.
3D model of reel drum frame
ROPS being tested
We are also able to assist with testing of Bullbars and bullbar subframes in accordance with UNECE reg 93.
Bullbar deflection testing at one of our clients
Independent Design Verification
Where our client has an existing design, or a design that requires independent 3rd party design verification, we can help.
In order to assist with an independent design verification, we would require the following information:
- Design Calculations
- Design Drawings (showing welding details, material standards and grades)
- Description of Use
Verification Process
Safe design is verified by ensuring that:
- the information issued by the designer for construction has all necessary information to convey design intent. This usually involves quality control processes during the design and construction process.
- the design achieves the occupational safety and health, and environmental outcomes required under applicable legislation. This applies for all life cycle stages, including requirements for:
- safe construction (e.g. erection of buildings or parts of buildings)
- operation and maintenance (this typically involves auditing against the requirements of original design intent as well as the statutory requirements of the design)
- decommissioning
Minimum Requirements
All designs should have a minimum level of suitable verification to satisfy the above requirements (e.g. design of safety, control and process systems).
As the potential risk associated with error in design increases, so should the level of verification. For example, pressure vessel failure is usually catastrophic and has a high risk to life consequence. So for pressure vessels and similar high-risk designs, the depth of verification and requirements for indepent verifier are higher.
Further information: Under the Mines Safety and Inspection Regulations 1995, registration of classified plant can only be completed following ‘verification by a person other than the person who prepared the design that the design complies with the Australian Standard applicable under regulation 6.33.’
Below is an example of a design verification plot for a vacuum vessel:
Short description of FEA
The first step in computer modelling is drawing the equipment or tool in three dimensions. Then the CAD software meshes the model by subdividing it into smaller elements. Afterwards the loads and constraints are added and the resultant stresses and deflections are calculated for each element. 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.
If you are unsure of the process, please contact us: give us a call or send us a message. Here is some information as provided by the WA department of mines, relating to industry regulation and safety.
