3. Crash test configurations and dummy instrumentation for side pole and oblique scenarios

Side-impact injury analysis depends entirely on how faithfully a test configuration reproduces the real-world collision it is meant to represent. A pole impact, an oblique moving deformable barrier (OMDB) strike, and a far-side occupant exposed to a struck-side intrusion are three distinct loading environments, each demanding its own barrier hardware, impact kinematics, and dummy channel set. This chapter explains what each configuration physically is, how it is set up and validated, and which instrumentation channels actually carry the injury-relevant signal. The goal is practical: after reading, you should be able to specify a test matrix, wire a dummy correctly, and judge from the data whether a run is valid.

Pole Impact: Rigid, Narrow, and Localized

In a side pole test, the vehicle is propelled laterally (or at an angle, depending on the regulatory variant) into a rigid cylindrical pole. The pole is narrow relative to the vehicle, so the barrier does not distribute load across the door the way a flat barrier does. Instead, the pole concentrates force over a small contact patch, producing deep localized intrusion, high local acceleration, and a characteristic "wrapping" of the occupant around the intruding structure. This is why pole tests are the reference configuration for head-to-pole and thorax-to-intrusion injury mechanisms.

Key setup parameters that must be controlled and documented:

• Pole geometry and foundation: diameter (commonly 254 mm in many regulatory pole tests), rigidly anchored to a non-yielding base. Any compliance in the mounting changes the intrusion pulse.
• Impact velocity and angle: the vehicle is typically towed at a defined speed with a defined yaw or crab angle relative to the pole. Record the actual measured velocity at contact, not the nominal setpoint.
• Impact point: the longitudinal position of pole contact along the vehicle side, referenced to a vehicle datum. A shift of even 100 mm moves the load path from the B-pillar to the door mid-panel and changes occupant loading substantially.
• Vehicle attitude: ride height, tire pressure, and steering state must match the specification, because they alter the vertical position of the pole relative to the sill and the occupant's H-point.

Validation of a pole run is largely a matter of checking the intrusion and pulse. Compare the measured door inner-panel intrusion trace and the sill lateral acceleration against the expected corridor. A run where the pole glances off the bumper structure rather than engaging the door will show a short, low-amplitude pulse and abnormally low intrusion — a classic invalid test that must be rejected before any dummy data is interpreted.

Oblique Moving Deformable Barrier (OMDB)

The OMDB configuration addresses a gap the perpendicular MDB and the pole test leave open: real side crashes frequently occur at an oblique angle, with the striking vehicle's front end engaging the target vehicle's side at something other than 90°. In an OMDB test, a moving deformable barrier — a trolley carrying a deformable honeycomb or equivalent face — is driven into the stationary or moving target vehicle at an oblique angle. The deformable face is essential: it represents the striking vehicle's crushable front structure and produces a longer, more distributed loading pulse than a rigid pole.

Setup considerations specific to OMDB:

• Barrier face stiffness: the deformable element's force-deflection characteristics must match the specification; a face that has been used repeatedly or stored improperly will not reproduce the intended pulse.
• Impact angle and overlap: the oblique angle and the lateral overlap determine which target-vehicle structures are engaged. Document both, and verify the actual contact geometry from high-speed video rather than assuming the nominal values.
• Barrier speed and mass: the trolley mass and impact speed together set the momentum delivered. Record measured speed at contact.
• Target vehicle state: whether the target is stationary or moving, and its orientation, must match the test protocol; a moving target changes the relative velocity and the occupant's pre-impact posture.

The OMDB pulse is longer and lower in peak than a pole pulse, so the dummy response is dominated by different mechanisms — more sustained lateral acceleration of the torso and greater potential for far-side excursion. This is precisely why the OMDB and pole configurations are not interchangeable and why a test matrix for far-side protection typically includes both.

Far-Side Occupant Setups

A far-side occupant sits on the side of the vehicle opposite the impact. In a struck-side pole or OMDB event, the far-side occupant is not directly loaded by the barrier; instead, they are accelerated by the vehicle's lateral motion and then interact with the interior — the center console, the far-side door, the seat, and the seatbelt. The dominant injury pathways are head excursion across the vehicle and contact with the far-side interior, plus torso loading through the belt.

Configuring a far-side test therefore requires attention to the occupant's restraint state and the interior geometry on the non-struck side:

• Restraint condition: belted versus unbelted is a first-order variable. For belted far-side occupants, the belt geometry and anchor positions on the far side matter as much as the buckle side.
• Seat and console geometry: the center console height and stiffness, and the far-side door trim, define the contact surfaces the occupant's head and torso will reach.
• Occupant position: the dummy's seated position, including any specified offset from the seat centerline, must be set and verified before the run.

Dummy Instrumentation Channels

The dummy is only as useful as its instrumentation. For side and oblique scenarios, the channels that carry the injury-relevant signal fall into a few groups. The table below summarizes the core channels and what each is used to evaluate; exact channel names and mounting locations follow the dummy manufacturer's specification and the applicable test protocol.

Two instrumentation practices deserve emphasis. First, channel polarity and coordinate systems must be defined once and applied consistently across every channel and every figure in the analysis; a sign error in a lateral acceleration channel can invert the apparent direction of head excursion. Second, all channels must be sampled at a rate adequate for the event — side impacts contain high-frequency content, and under-sampling will alias the peak. Verify the sample rate and anti-alias filtering settings before the run, not after.

The figure below maps the three configurations to their loading character and the instrumentation emphasis each one demands.

Building a Coherent Test Matrix

Because the three configurations probe different mechanisms, a defensible far-side and oblique injury program treats them as a matrix rather than a single test. A practical starting point is to pair each impact configuration (pole, OMDB) with each occupant position of interest (struck-side, far-side), and to vary restraint state where the protocol permits. For each cell, record the configuration parameters (velocity, angle, impact point, barrier condition), the dummy position measurements, and the full channel list with polarity and sample rate. This record is what allows a later analyst to distinguish a genuine injury finding from a setup artifact.

When a run produces an unexpected result — for example, a far-side head excursion far below expectation — the first diagnostic step is not to question the dummy but to check the configuration: was the impact point correct, did the barrier engage as intended, was the dummy positioned per specification, and were the channels correctly scaled and polarized? In practice, most anomalous far-side results trace back to one of these setup variables rather than to the occupant response itself. Treating configuration validation and instrumentation verification as inseparable from the test itself is the discipline that makes side and oblique crash data trustworthy.