Domain: Engineering — Structural Engineering
Target concept: Effect of Connection Type on Structural Stiffness

Video generation prompt: Two steel sub-panels are presented side by side on the test rig, with the left one representing bolted connections between middle plates and the right one representing welded connections between middle plates, under cyclic horizontal loading.

Evaluation guide:
(i) Target concept: Structural stiffness differential arising from connection kinematics. Bolted joints permit rotational freedom and interface slip, while welded joints enforce full moment transfer and continuity.
Minimum mechanism: Cyclic horizontal load must induce in-plane shear at the middle plate interfaces; stiffness contrast must manifest as differential lateral displacement amplitude and joint integrity (gap vs. no gap), not bending of panels themselves.
(ii)Storyline: Frame opens on static wide shot of test rig with two steel panels side-by-side (left bolted, right welded); loading begins → both panels deflect horizontally → left panel deflects farther and shows transient gap opening at bolted interface; right panel deflects less and maintains seamless joint; unloading occurs → left panel retains small residual offset/gap, right panel fully recovers; final frame holds contrast. All events occur in fixed frontal viewpoint; no cuts; panels never leave frame; lighting remains consistent; motion is smooth and synchronous with actuator cue.

Manual:
Experimental Procedure
1. Mount two identical steel sub-panels side-by-side on a rigid test rig.
2. Configure left panel with bolted connections between middle plates; right panel with welded connections.
3. Apply cyclic horizontal loading via hydraulic actuator.
Observation of Experimental Phenomena
Under loading: left (bolted) panel exhibits larger lateral deflection and visible joint gaps; right (welded) panel shows smaller deflection and no joint separation.
Summary of Experimental Principles
Bolted connections allow relative slip and rotation at joints, reducing overall structural stiffness; welded connections provide monolithic continuity, increasing stiffness and limiting deformation.

Prompt Grounding rubric:
level_1: Fewer than two steel sub-panels appear, or no test rig is shown; if two panels are present they are not set up as a left/right pair (e.g., a single panel only, or the panels stacked or overlapping instead of standing side by side), and nothing marks either panel as bolted or welded.
level_2: Two rectangular steel panels are visible but are not mounted together as a left/right pair on one shared rig (e.g., on separate stands, or one clearly off the rig), or neither panel's joint construction (bolted vs. welded) can be told apart, or no horizontal loading actuator/frame is shown.
level_3: Two steel sub-panels sit side by side on one shared test rig, the left one built with a bolted middle-plate joint and the right one with a welded middle-plate joint, each visually identifiable as such; a horizontal actuator or loading frame is present and aimed to push the panels sideways; neither panel is stacked on, rotated relative to, or overlapping the other.
level_4: Everything required for score 3 holds, and the bolted panel's middle-plate joint shows visible bolt heads or a bolt-hole pattern, and the welded panel's middle-plate joint shows one continuous fused seam line, and both panels stay fully inside the frame for the entire shot.
level_5: Everything required for score 4 holds, and at least three separate bolt heads line up across the bolted panel's joint, and the welded panel's seam runs unbroken across the full width of its joint, and both panels keep the same size, tilt, and position relative to the rig and camera for the whole shot, with neither one drifting, rescaling, or rotating on its own.

Scientific and Causal Correctness rubric:
level_1: The two panels deflect the same way under the cyclic load, or neither panel visibly moves at all; nothing on screen suggests that a bolted joint behaves differently from a welded one under lateral load.
level_2: The panels move, but not sideways the way horizontal cyclic loading would push them (e.g., they rock up and down or twist instead of sliding laterally), or only one panel visibly responds to the load while the other stays put for no shown reason; no sway-amplitude contrast tied to joint type is visible.
level_3: Both panels visibly sway sideways as the actuator cycles; the bolted (left) panel swings farther than the welded (right) panel on each pass, and this gap in sway amplitude between the two holds up across at least two full loading cycles shown.
level_4: Everything required for score 3 holds, and at peak sideways load the bolted panel's middle-plate joint visibly opens a gap or its bolt holes appear to elongate, while at that same moment the welded panel's seam stays shut with no visible split.
level_5: Everything required for score 4 holds, and once the load releases, the bolted panel settles back short of its starting position, leaving a visible residual gap or looseness at the joint, while the welded panel springs fully back to its original shape with the seam closed and undistorted, and this contrast in recovery is shown at the same point in time for both panels, not staggered.

Spatiotemporal Consistency rubric:
level_1: A panel appears in a new spot with no motion linking the frames, a panel visibly splits or breaks apart mid-shot, the lighting or shadow on the rig flips abruptly (e.g., full shadow to a bright highlight) with no cause, or the camera cuts or zooms away from the fixed frontal framing shown at the start.
level_2: One panel drifts sideways by a clearly noticeable amount between two consecutive frames with no matching actuator motion, or a bolt head or seam segment blinks in and out of view for a couple of frames, or the lighting gradient across the rig flips direction mid-sequence without cause, or the horizontal actuator rod appears to separate from or pass through the panel it is pushing without contact.
level_3: Neither panel jumps to a new position or breaks apart, no bolt head or seam segment flickers in and out of view, and the highlight on the bolt heads and the shadow beneath the rig both stay on the same side of the frame for the whole clip; the camera keeps its fixed frontal framing throughout, and both panels slide smoothly with no floating, jerking, or rubbery warping.
level_4: Everything required for score 3 holds, and the panel edges stay crisp rather than smearing during the sideways motion, and the bolt heads and weld seam keep the same shape and count from frame to frame, and neither panel edge appears to glitch in front of or behind the other.
level_5: Everything required for score 4 holds, and both panels travel in a straight horizontal line with no vertical bobbing, and the side-by-side spacing and parallel alignment between the two panels looks the same by eye from the first frame to the last, and the clip shows no strobing, skipped frames, or repeated frames.