3. Test article preparation

Before a single accelerometer is bonded or a barrier is positioned, the test article itself must be received, documented, and frozen into a known baseline state. Crash test results are only defensible if the vehicle that hit the barrier is provably the same vehicle that was measured, weighed, and photographed beforehand. This section covers the preparation chain that converts a delivered vehicle into a traceable, instrumented test article: receipt inspection, documentation control, fluid and tire conditioning, and the photographic and dimensional records that anchor every later measurement.

Vehicle Receipt and Identity Verification

The receiving engineer's first job is to confirm that the delivered vehicle matches the test request. This is not a formality — build variants, trim levels, and running changes mean two visually identical vehicles can differ in curb mass by tens of kilograms or in structural content at the front rail. Verify the VIN against the test authorization, then record the build date, powertrain code, and any optional content that affects mass or stiffness (sunroof, tow package, battery pack variant).

Inspect for transport damage before signing the carrier's release. Photograph any pre-existing damage immediately, because a dented door or scuffed bumper discovered after the test cannot be distinguished from test-induced deformation. Record the odometer reading; a vehicle with delivery mileage has been driven, and its tires and brakes are no longer in as-built condition.

Documentation Package

Assemble the documentation before conditioning begins, because several records must reflect the as-received state. A complete package for a typical frontal or side impact test includes:

• Test authorization and configuration sheet (impact speed, overlap, barrier type, dummy configuration)
• VIN decode and as-built specification, including curb mass and weight distribution
• Delivery condition report with damage photographs
• Fluid fill record and tire pressure log
• Pre-test photographic index and dimensional survey sheet
• Instrumentation channel list cross-referenced to sensor locations

Version-control these documents. When a test configuration changes — say, the impact speed is revised from 56 km/h to 64 km/h — every downstream record must reference the revision that was actually executed. A dimensional survey taken against a superseded configuration sheet is worse than no survey, because it looks authoritative while describing the wrong test.

Fluid Levels and Conditioning

Fluid state affects both mass and the post-test fire and spill assessment. Drain or top up to the specification called out in the test request. For most full-vehicle crash tests, the fuel tank is filled to a defined level with a specified surrogate or actual fuel, and the fill mass is recorded. Coolant, oil, brake fluid, and washer fluid are set to nominal full. Record each fluid's type and quantity, because a later mass discrepancy of 15 kg is easily explained by a full versus half-full fuel tank.

Battery state matters for two reasons: mass, and the risk of post-impact thermal events in electrified vehicles. Record state of charge and, for high-voltage systems, confirm the service disconnect procedure and its documentation. If the test plan requires the high-voltage system to remain energized, that decision must be explicit and traceable.

Tire Pressure and Tire Condition

Set cold tire pressure to the placard or test-specified value, and record it per corner. Tire pressure changes ride height, which changes the vehicle's pitch attitude at impact and therefore the effective bumper height relative to the barrier. A 30 kPa error across an axle is enough to shift the impact point measurably.

Measure and record tread depth at three points per tire, and note any flat spots, sidewall damage, or mismatched brands. Tires are consumables that arrive in unknown condition; documenting them protects the test from being invalidated by an unexplained asymmetry. Set pressures with the vehicle at ambient temperature and re-check immediately before the run, since a vehicle staged in direct sun can gain 10–15 kPa on the sunlit side.

Pre-Test Photographic Record

The photographic record must be systematic, not ad hoc. Shoot a fixed set of views so that pre- and post-test images can be compared directly:

• Six orthogonal exterior views: front, rear, left, right, top, and a three-quarter overview
• Interior views: driver and passenger compartments, seat positions, head restraints, and floorpan
• Undercarriage and engine bay, including the front rail and bumper beam attachment points
• Close-ups of every sensor mounting location before and after sensor installation
• Reference-scale images: a tape measure or scale bar in frame for any dimension that will be compared later

Use consistent lighting and a fixed camera distance where possible. Include a slate or card in the first frame of each session showing the test ID, date, and view label. This is what makes the archive searchable months later when the report is being written.

Dimensional Survey

The dimensional record establishes the as-built geometry against which post-test deformation is measured. Survey the vehicle on a level surface or a coordinate measuring table, and record at minimum:

Record each value with its measurement uncertainty. A ride height quoted to the nearest millimeter from a tape measure is not the same as one from a laser tracker, and the report should say which was used. Where the manufacturer publishes datum points, use them; where none exist, define your own reference points and document them with photographs so the post-test team measures the same locations.

Freezing the Baseline

Once fluids are set, tires are logged, photographs are indexed, and dimensions are recorded, the vehicle's state is frozen. From this point forward, any change — a sensor added, a seat adjusted, a door opened for an extended period — must be logged against the baseline. The value of this discipline becomes obvious during post-test analysis: when the measured crush depth differs from prediction by 40 mm, the team needs to know whether the pre-test ride height was actually at specification or whether a low tire quietly changed the impact geometry.

A practical check before releasing the vehicle to instrumentation: re-weigh it and compare against the sum of the as-built curb mass plus recorded fluid and ballast additions. A discrepancy greater than about 1% of total mass usually indicates an unrecorded item — tools left in the trunk, a missing spare tire, or a fluid level that was not actually set as logged. Resolve the discrepancy now, while the vehicle is still accessible, rather than discovering it in the mass report after the test.

The preparation chain described here is deliberately sequential: identity verification enables correct documentation, documentation defines the conditioning targets, conditioning produces the baseline records, and those records make the post-test comparison meaningful. Skipping or reordering stages does not save time — it moves the cost to the analysis phase, where it is far more expensive to resolve.