Date: 03/12/2022

Author: Raghavendra Kamat

CAE Driven Virtual Validation of Lighting performance

Modern Day Headlights serve many additional functions apart from illuminating the roadways. They are equipped with projector lamps with thermal management systems and integrated Daytime Running Lights (DRL). The housing of headlamps facilitates mounting points for front exterior systems, acts as a link between BIW and exteriors. Future headlamps also host many sensors and cameras of ADAS features. Headlamps of a Full-size SUV or a truck hosting all the innovative lightning technologies typically range from 6 to 8 kg/lamp. The majority of functional parts are mounted on Headlamp housing which also facilitates the hard and soft mountings for exterior sub-systems. Meeting the OEM performance standards for durability and regulatory requirements on the field is a challenging task for such heavy headlamps. But with the sophisticated CAE tools and the methodologies developed especially to meet headlamp performance requirement makes it easier to develop the product in a timely and cost-effective manner.

What eShocan offer:

Product development and virtual validation of Headlamp involves the prediction of loads, material selection, and optimized designing of headlamp body in a robust manner to meet all following design performance parameters with aid of available CAE tools and methodologies

Design for Stiffness

• Involves designing of Headlamp to meet established Natural frequency and FRF targets (typically ranges from 45 to 50hz)
• Headlamps with sensors, cameras for ADAS features, and washer system require a more robust design to meet frequency response and sensor-related targets
• Optimized tab attachment to the body, type of fastener, and its locations
• Optimized additional bracket design to support soft mounts for exterior and closure subsystems
• Tab deflection strength while assembling
• Aim deflection strength

Design to Sustain for Fastener loads

Headlamps mounted on pickup trucks, full-size SUVs, and offroad vehicles delivers high acceleration on the fasteners in case of a pothole or in an offroad event resulting in loosing of torque. This causes more stress on the other mounting tabs and cracks can develop. These types of failure can be avoided with selective load prediction and implementing the following design principles

• Predicting loads to each mounting tab.
• Involves designing of tabs and body brackets to overcome toque and shear loads
• Introducing steel compression limiter to the tabs where predicted loads exceed the fastener torque values.
• Reducing the overall mass of headlamp with CAE optimization

Design for Durability and Fatigue

• Design to meet the stresses caused by vibration fatigue from the shaker table test
• Design to meet the stresses caused by duty cycle fatigue
• Stress assessment for reinforced plastics with the help of DIGIMAT coupling
• Design to meet the cyclic thermal stresses caused by high and low temperatures
• Design to withstand the stress caused by a high acceleration in case of the pothole and offroad events

Design for FMVSS/ECER Regulatory

• Design to meet the FMVSS/ECER Low-speed regulatory requirements. • Design to meet for the Pedro compliances

Multi-Disciplinary Optimization

eShocan offers multi-disciplinary optimization to meet all performance parameters with less lead design timeline.

Engineering Change Request (ECR) notice is a common process that almost all parts undergo during their lifecycle. A single part can undergo multiple ECR’s during its lifecycle. There were multiple cases where each ECR was handled by different Engineer based on their availability The main highlights of the check sheet are listed below.

• The check sheet had classification based on complexity of changes and number of parts involved in each ECR.
• The Engineer has to follow the check sheet and mark their initials on the check sheet against each and point and submit it along with the data.
• Doing this made it easy for the Engineers to understand the history of the changes made to the part and modify the data easily.
• The time required to process each ECR reduced by 30% and quality of CAD and drawing increased by 50%.

Challenges and Objectives:

Since each person had different style of handling the CAD and drawing there was no consistency between the changes and the quality of CAD and drawing kept going down when each Engineer handled the changes.

This in turn caused confusion and made the lead time for implementation of ECR changes longer and harder to track. So the customer wanted to improve the quality and have a common process across the entire organization we implemented a quality check sheet which had checks to ensure the changes were made to CAD and drawing following a particular process and check points which made anyone working on the parts easy to understand and modify the parts later.

Implementation of a single process across different which had different methods of working was a challenge. The check sheet had to robust and fool proof with scope to add improvements at a later stage if required.

How Product/Service Helped:

We created a check sheet template that was in a excel format which each engineer working on a ECR can retrieve from a common database accessible to all engineer’s working on the project. This check sheet was very comprehensive and was made to cater each department based on the type of ECR’s they receive. The check sheet was further classified based on the complexity of the task, type of change being made, number of parts involved and if changes are being made to drawing or CAD alone.

Implementation of this check sheet created a streamlined process across the organization and reduced efforts wasted in understanding the history and rework. Since the check sheet was completely online it could be retrieved anytime by just a click of a button.

Engineers were able to track each part undergoing changes which were part of the ECR and the check sheet ensured changes required on all parts are being done without missing any parts while delivery.

Quotes:

“Quality is never an accident; it is always the result of high intention, sincere effort, intelligent direction and skillful execution; it represents the wise choice of many alternatives.” – William A Foster. Continuous improvement is better than delayed perfection – Mark Twain.