Truss Joint Force Calculator
Solve a determinate two-member planar truss joint with tension positive; not a whole-truss or support stability solution. Caller independently establishes units, regime, calibration and applicability; this does not establish design-code compliance, authenticity, operational safety, treatment efficacy or a validated forecast.
Description
Two unknown truss forces can be resolved from planar joint equilibrium.
Two unknown truss forces can be resolved from planar joint equilibrium.1
Member directions and the sign convention must be established before interpreting the solved forces. Use this tool to calculate truss Joint Force from the supplied measurements and assumptions.
When to use Truss Joint Force Calculator
Use this tool to calculate truss Joint Force from the supplied measurements and assumptions. Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
How to use Truss Joint Force Calculator and understand its results
- Establish the SI units or caller unit basis, load signs, measurement interval, model conditions and independently chosen coefficients or references.
- Enter memberDirectionCosines, externalJointForce, using the field meanings and rules below, then run the tool.
- Read signedMemberForces. Interpret the fields using their units, signs and evidence conventions below.
- If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| memberDirectionCosines | Member direction cosines | list of list of number | Required |
| externalJointForce | External joint force | list of number | Required |
Enter exactly two planar unit member directions and a two-component external force. Each direction's norm must be within 1e−10 of one. Solve the 2×2 equilibrium system for member forces; unresolved parallel directions fail. Positive forces act along supplied directions, representing tension only if those directions point away from the joint.
[direction1 direction2]×[F1,F2]=−externalForce Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| signedMemberForces | Signed Member Forces; follow the units, sign, ordering and evidence convention stated above | list of number |
{
"input": {
"memberDirectionCosines": [
[
1,
0
],
[
0,
1
]
],
"externalJointForce": [
-3,
-4
]
},
"output": {
"signedMemberForces": [
3,
4
]
}
}Limitations and assumptions
Member directions and the sign convention must be established before interpreting the solved forces. Interpretation depends on the units, sampling scope and exact model described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.
Alternative or Complementary methods
Use Strut-and-Tie Force Calculator for this related task: A strut-and-tie force calculation requires an independently formulated equilibrium system.
Use Steel Connection Moment Calculator when its separate inputs and assumptions fit the question: A connection moment sums force contributions with signed lever arms.
References
-
Truss Joint Force Calculator — tool.io
Similar or alternative tools
- Strut-and-Tie Force Calculator
A strut-and-tie force calculation requires an independently formulated equilibrium system.
- Steel Connection Moment Calculator
A connection moment sums force contributions with signed lever arms.