Vibration Isolation Transmissibility Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-with-binding-errata

Evidence ID

t6-116

Effect

Computation or source lookup only

Input and validation requirements

The specification leaves frequency units ambiguous, causing substantially different transmissibility results, and it does not explicitly define rejection behavior for zero stiffness or the exact r=sqrt(2) boundary.

Required corrections

[
  {
    "vector": 4,
    "field": "natural_frequency/r/TR/isolation",
    "wrong": "1 Hz / 1.732 / 0.5 / 50%",
    "correct": "3.1623 Hz / 0.5477 / 1.4286 / -42.9% for the GIVEN m=50 kg",
    "cause": "vector designed for m=500 kg (to hit r=√3) but shipped m=50; working asserts sqrt(19739.2/50)/(2π)=1 Hz which is arithmetically false (=3.1623)"
  }
]

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "disturbing_frequency_hz": 2,
    "isolator_stiffness_N_per_m": 3947.84176,
    "mass_kg": 100,
    "damping_ratio": 0.05
  },
  "expected_outputs": {
    "natural_frequency_hz": 1,
    "frequency_ratio_r": 2,
    "TR": 0.339181733,
    "isolation_percent": 66.081827,
    "required_static_deflection_m": "not defined by the supplied specification"
  },
  "working": "f_n=(1/(2*pi))*sqrt(k/m)=(1/(2*pi))*sqrt(3947.841760/100)=(1/(2*pi))*6.283185307=1 Hz. r=f/f_n=2/1=2. 2*zeta*r=2*0.05*2=0.2. Numerator=sqrt(1+0.2^2)=sqrt(1.04)=1.019803903. Denominator=sqrt((1-2^2)^2+0.2^2)=sqrt(9+0.04)=sqrt(9.04)=3.006659276. TR=1.019803903/3.006659276=sqrt(1.04/9.04)=0.339181733. Since r>sqrt(2), isolation=(1-0.339181733)*100=66.081827%."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche6/tranche6-results.json
• tranche errata record