Hood design-Week 2

Hood design in Nxcad

In this challenge we create a hood design for a car with Nxcad

While designing the any hood for any car there are certain guidelines & standards which need to be follow for better design.

There are some key points which needs to be consider while designing the hood, like the region for which the car is designing because according to this opening angle of the hood will change, crash regulations , pedestrian safety, functional requirement, reinforcement & support rod or gas tray for opening of hood, these are the some key point which needs to taken care while designing.

Now for this challenge we get some input data, like class A surface (outer panel), Master section data, hinge & striker assy part.

First we import all the part files in the NX, the we create copy of the class A surface and define as the working surface for our inner panel of hood.

Then first we create the tooling axis for the part, this the main working direction for the tooling, and for this part every vertical sheet will we create with respect to this tooling direction having certain draft angle accordingly

Then we refer the master section data, and then creates flanges with the help of offset sheet & curve on sheet, then we join all these flanges with through curve & provide the blends for the edges.

After creating the flanges then we create the embossed structure design to strengthen the sheet, for the height of the emboss we need to consider the master section data and accordingly we give the height in two steps & also we provide the draft angel to the emboss (should not less then the 7°) accordingly in tooling direction

After creating the flanges now we provide the cut out on the upper embossed face for the mastic, so that the inner panel & outer panel can join with the help of mastic properly & reduce the noise while riding, after this we mirror the sheet and then we sew both sheet together as we done all the above working on the one half of the sheet.

Now time to create the plane face/surface for the hinge mounting, for that we create the new datum plane close to the inner panel, then with the help of emboss command we create the flat face for the hinge, but in this emboss in end cap section we select the datum which we created so that we can get a nice flat surface, after that we activate the hood assembly, in hood assy., first we provide the constrain to the hinge assy. to the inner panel to join them properly after that we use the mirror assy. feature to create hinge joint to the other side of the panel.

Now for the striker, first we create the axis of rotation for the hood by using hinge assy., after identifies the axis of rotation then we create the trajectory of the hood, for that we create a datum plane at center of the axis of rotation, by this datum plane we draw circle at certain radius which represent the trajectory of the hood, then we create two line at certain angle at same radius of the our last circle, then we draw another line tangent (line T1) to the previous line which we created at an angle, because the trajectory of the striker must be tangential to the hood trajectory,

After this we activate the striker part in assy. Model, now again we create a datum plane in center & after that we create a horizontal line (Line T2) in b/w of 'C' hook of the striker, now we assemble the striker to the inner hood panel, for that we make constrain the horizontal line T2 of striker with the tangent line T1 to the trajectory of the hood.

After this we create base surface for striker on inner panel, for this we extract the bottom surface of the striker, then extend sheet at 5~8 mm then we use law extension method to create nice flat surface for striker with a draft angle of 10~12° and then provide the blends on the edge.

Now we remove the Sharpe corner of the hood inner panel by using bridge curve, after this we provide the thickness (0.75 mm) to the inner panel as per the master section data & the direction of the thickness should be upward side.

Now time to create the hemming for the hood, hemming is process by which we join both the inner & outer panel together with having certain mm of clearance & also we should give the hemming relief to the corner to reduce the stress concentration at the corner parts, for hemming first we offset the outer panel as per the master section, then we create a flange on to this surface by using offset curve on sheet and then trim of the sheet with this curve, now join both outer panel & this flange together by using law extension command, then to provide the blend to the edges we use the 3face blend, by this we form a nice curved sheet, then we provide the hemming relief to the corner by using the curve on face command, and their is min. 3 mm clearance should be their in b/w hemming edges.

After creating the hemming we create the thickened surface of the outer panel.

Last we perform the checks for any collision, any gaps or any other issues in the design, if no issues found then our design is ready to submit.