Analysis of Bracket Failure and Impact Resistance

Overview of Incident

A bracket on a test vehicle has become the focus of an incident which occurred at a loading bay during some preliminary cold weather tests in Canada that was measured around - 20 oC on the day in question. The bracket part has a small boss were the bush is mounted. It is also known that the manufacturer looked to save costs and changed the original material specification and used 1023 Carbon Steel Sheet (SS) instead of that proposed.

 

At the incident scene, the bracket showed signs of early failure. The rubber engine mounting bush was missing and the retaining nut was loose.
The driver of the test vehicle hit a 135mm curb when approaching the loading bay.

 

The driver claimed that he was not travelling more than 20 MPH when he hit the kerb. However, there is some dispute which has resulted in a court case. Acting as an expert witness you are asked to carry out further analyses to either support or refute the drivers claim by checking the initial crashworthiness of the bracket.
Information regarding impact related behaviour is supplied in fig 3 below; Use this to predict the behaviour of the bracket under this type of scenario described above.

 

You need to complete the court Incident Report attached. Note that Part 1 of the report needs to be prepared for a non-technical audience. Part 2 is to be populated by using your analysis to technically describe the suitability of the bracket to withstand impact and state clearly your assumptions you have used.

 

Suggest design changes that would make the bracket more effective to impact.
The bracket is mounted against a solid surface using the four 12mm diameter holes.
The Force is applied normal to the face shown blue in Fig.1.
The force is shared equally between two brackets. The engine has a range of 900 –
5000 revolutions per minute and a load of 0.8KN.

Use finite element techniques to analyse the bracket and:
• Determine the Maximum load the bracket can carry under impact
• Determine the maximum allowable impact speed.
• State the type of failure and appropriate Factor of Safety
• Suggest design improvements based on your analysis findings

 

Submission Requirements:
You are to use the Incident Report sheet attached and complete both parts. You are not permitted to alter the format. Adhere to page limits, use clear annotated images, and avoid lengthy texts.
The report must be in pdf format and submitted to Turnitin. You are not required to upload part files but retain them safely on your system so they can be retrieved if equested. Detailed feedback will be provided via Grademark within Turnitin.
Once the report has been submitted you will be expected to defend your statements in a short discussion session.