A mechanical shock requirement for a surface mount PCB jumper should identify peak acceleration, duration, pulse shape, directions, count, mounting and acceptance criteria. A peak value alone cannot reproduce a test. Random-vibration Grms is not interchangeable with a shock peak.
The same peak can have a different duration
Vibration Research describes controlled transient events using shape, amplitude and duration. Its course compares classical pulses and compensation waveforms. These sources support a complete pulse definition, not a test severity for a particular PCB assembly.
For illustration, assume an ideal half-sine main pulse a(t)=apeak×sin(πt/T), for 0≤t≤T. Its main-pulse velocity change is Δv=2apeakT/π. With apeak=100 m/s² and T=10 ms, Δv is approximately 0.637 m/s. At the same peak and T=5 ms, it is approximately 0.318 m/s. Equal peaks do not give equal main-pulse integrals.
| Requirement or record | Units or contents | Reproduction purpose |
|---|---|---|
| Peak and duration | m/s² and ms with definitions | Amplitude and time scale |
| Shape and tolerance | Target shape and measured time history | Actual input conformity |
| Directions and count | Board coordinates, signs, number | Applied shock sequence |
| Mounting and monitoring | Fixtures, supports, sensors, criteria | Assembly constraints and response |
The calculation does not rank joint damage
The integral covers only an ideal unipolar main pulse. A shaker may add pre/post compensation, so it is not the net velocity change over a complete cycle. Δv alone does not establish solder-joint damage or an allowable drop height.
Board support, jumper position and structural response matter. A compliant control-point pulse does not mean identical local response at every joint. Save sensor locations and measured histories. Handle out-of-tolerance events under an approved procedure rather than treating extra input as automatic proof of qualification.
Define electrical checks in the plan
For surface mount PCB jumpers, specify required before/after visual, resistance and connection checks, and whether in-test intermittent-open monitoring is needed. Record sampling, bandwidth, triggers, thresholds and duration criteria. Post-test continuity alone cannot exclude a brief opening during shock.
Random-vibration PSD and Grms records concern a different input. Retain separate requirements, data and conclusions. This example establishes no Hongchuan shock rating.
Questions
Is a larger peak always more severe? Duration, shape, structural response and acceptance criteria must also be considered.
Can a loose-part result qualify a soldered board? Have the responsible team confirm applicability to the different mounting and structural boundaries.
References
Vibration Research shock basics; VRU classical pulses and compensation.
Cover is an AI-generated shock concept, not Hongchuan equipment, curves or results. Ideal calculations provide no test severity or shock-resistance rating.