Has ISOKLAMP CFR been physically tested?

No. Every ISOKLAMP figure on this page is model-predicted from closed-form bolted-joint mechanics to VDI 2230 Sheet 1 and finite-element analysis. No physical testing of ISOKLAMP hardware has been performed.

Where do the baseline figures come from?

Baselines for the other nine methods are reconstructions calibrated against published data, with the source given per row in the calibration table on this page.

Residual clamp force for ten securing methods

Under DIN 25201-4:2010-03 Annex B clause B.6, a securing element passes if more than 80 % of the pre-stressing force remains after 2 000 load cycles and the curve gradient does not indicate subsequent complete loss. Below is the full modelled dataset against that criterion at F_V = 70,0 kN, t_s = ±0,60 mm, f = 12,5 Hz, n = 12 per configuration. Every ISOKLAMP figure is model-predicted, not measured.

Status of this data. All ISOKLAMP CFR performance figures on this site are model-predicted from closed-form bolted-joint mechanics (VDI 2230 Sheet 1) and finite-element analysis. No physical testing of ISOKLAMP hardware has been performed. Baseline figures for other locking methods are reconstructions calibrated against published data, with sources listed below. Patent applications are in preparation; none has been filed. ISOKLAMP CFR is not certified to 3-A, EHEDG, NSF, ATEX, DNV or any other scheme.

Test conditions

Modelled Junker transverse-vibration configuration, DIN 25201-4:2010-03 Annex B.
Parameter	Value
Bolt	M16 × 2,0, cl. 10.9
Pre-stressing force F_V	70,0 kN
Transverse displacement t_s	±0,60 mm
Frequency f	12,5 Hz
Cycles N	2 000
Replicates per configuration	n = 12

Results at N = 2 000

Residual clamp force as a percentage of F_V after 2 000 cycles, mean ± standard deviation, n = 12. ISOKLAMP CFR is model-predicted.
Method	Residual clamp force	SD
Unsecured plain washer	0,0 %	± 0,0
Split spring washer	0,0 %	± 0,0
Nylon-insert nut	4,0 %	± 3,1
Double nut	23,4 %	± 14,0
Serrated flange nut	48,6 %	± 9,2
Anaerobic threadlocker	62,3 %	± 18,0
All-metal locknut	71,8 %	± 6,4
Thread-form nut	85,3 %	± 4,1
Wedge-locking washer pair	92,1 %	± 1,4
ISOKLAMP CFR (model-predicted)	99,4 %	± 0,6

Master Junker curve: residual clamp force against cycle count for ten securing methods — Model-predicted. n = 12 per configuration.

Bar summary of residual clamp force at 2 000 cycles for ten securing methods — Model-predicted. Error bars are ±1 SD, n = 12.

Recovery signature

Mode B — stage 1 relaxation

Residual clamp force against imposed stack shortening for rigid, Belleville and ISOKLAMP stacks — Model-predicted. M16, F_V = 70,0 kN. Full series in the CSV below.

Residual clamp force vs imposed stack shortening, M16, F_V = 70,0 kN. Extract of isoklamp_stage1_relaxation.csv.
Stack shortening	Rigid	Belleville	ISOKLAMP CFR
0 µm	70,0 kN	70,0 kN	70,0 kN
50 µm	38,6 kN	62,7 kN	69,3 kN
100 µm	7,3 kN	55,4 kN	68,6 kN
150 µm	0,0 kN	48,1 kN	67,9 kN
200 µm	0,0 kN	40,8 kN	67,2 kN

Severity sweep

Residual clamp force across a sweep of transverse displacement amplitudes — Model-predicted. Transverse amplitude sweep.

Thermal cycling

Preload retention over thermal cycles between 20 and 120 °C. Model-predicted; baselines calibrated to Eraliev et al., Adv. Mech. Eng. 13(8), 2021. n = 5.
Thermal cycle	Plain washer	Wedge-locking pair	Belleville stack	ISOKLAMP CFR
1	85,0 %	86,8 %	94,5 %	98,9 %
5	66,7 %	69,3 %	84,4 %	97,1 %
10	56,9 %	59,9 %	78,3 %	95,9 %
20	51,3 %	54,5 %	74,4 %	95,1 %

Residual clamp force across ten installation and removal cycles — Re-use. Model-predicted.

Clamp force retention on a CFRP clamped part — CFRP clamped part. Model-predicted.

How the baselines were calibrated

Source used to calibrate each baseline reconstruction.
Method	Calibration source
Unsecured plain washer	Junker, SAE 690055, 1969
Split spring washer	NASA-STD-5020; withdrawn DIN 127 series
Nylon-insert nut	Published DIN 25201-4 Annex B series, manufacturer data
Double nut	Bickford, An Introduction to the Design and Behavior of Bolted Joints
Serrated flange nut	Published transverse-vibration comparisons
Anaerobic threadlocker	Manufacturer technical data sheets and published series
All-metal locknut	Published DIN 25201-4 Annex B series
Thread-form nut	Manufacturer-published Junker series
Wedge-locking washer pair	Manufacturer-published DIN 25201-4 Annex B series
Thermal cycling baselines	Eraliev, Zhang, Lee & Lee, Adv. Mech. Eng. 13(8), 2021

The honest gap in this comparison. The nine baselines are reconstructions of other people’s measurements, run in other people’s fixtures. The ISOKLAMP column is a model. They have not been run side by side in one laboratory on one rig, and until they have, the difference between the top two rows should be read as a modelled expectation and nothing more. An accredited independent series is costed and scheduled; we will publish it whichever way it goes.

Downloads

Questions

What is the DIN 25201-4 pass criterion?: Under DIN 25201-4:2010-03 Annex B clause B.6, a securing element passes if more than 80 % of the pre-stressing force remains after 2 000 load cycles and the curve gradient does not indicate subsequent complete loss.
Has ISOKLAMP CFR been physically tested?: No. Every ISOKLAMP figure on this page is model-predicted from closed-form bolted-joint mechanics to VDI 2230 Sheet 1 and finite-element analysis. No physical testing of ISOKLAMP hardware has been performed.
Where do the baseline figures come from?: Baselines for the other nine methods are reconstructions calibrated against published data, with the source given per row in the calibration table on this page.