Interpretation Response #04-0242 ([Cusco Fabricators, Inc.] [Mr. Pardhasarathi Chilukuri])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Cusco Fabricators, Inc.
Individual Name: Mr. Pardhasarathi Chilukuri
Country: US
View the Interpretation Document
Response text:
Oct 29, 2004
Mr. Pardhasarathi Chilukuri Reference No. 04-0242
Cusco Fabricators, Inc.
305 Enford Road
Richmond Hill, L4C3E9
Ontario, CANADA
Dear Mr. Chilukuri:
This is in response to your October 1, 2004 e-mail to Waider Wong, Structural Design Engineer, Federal Highway Administration, asking if Finite Element Analysis (FEA) or hand calculations may be used to verify that DOT 407 and DOT 412 series cargo tank bumpers, described here as rear-end protection devices, and rollover guards, described here as overturn protection devices, meet the performance requirements of the Department of Transportation"s (DOT"s) Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you ask if you can use hand calculations to verify the performance of the design for the non-linear portion of the deflection of an overturn protection device and a rear-end protection device.
The HMR do not require or prohibit FEA calculations to verify the performance of a particular design nor do they require or prohibit physical testing. Each cargo tank or cargo tank motor vehicle design type must be certified to conform to its specification requirement by a Design Certifying Engineer (DCE). See § 178.320(b)(1). The DCE"s responsibility for certifying the cargo tank motor vehicle design type includes verification of the method of analysis and its justification. If a manufacturer"s DCE can demonstrate by hand calculations that the accident damage protection devices meet the performance requirements for strength and/or displacement of the DOT 400 cargo tank series specifications, DOT will perform the same level of calculations to verify compliance with the requirements. On the other hand, if the manufacturer chooses to use FEA to justify its design, DOT will conduct an independent analysis with commercial FEA codes, such as ANSYS and Ls-Dyna, to validate the modeling output results. Also, § 178.320(b)(2) states the DCE must furnish to the manufacturer of a cargo tank that complies with its specification requirements a certificate to denote its compliance. The certificate and the required sketches, drawings, and calculations used to obtain certification must each be signed by the DCE.
I hope this satisfies your request.
Sincerely,
Hattie L. Mitchell, Chief
Regulatory Review and Reinvention
Office of Hazardous Materials Standards
178.320