JURA

JSAMS: Jura Strength Analysis Modules

The JSAM's are a collection of Joint strength analysis modules. There are eighteen JSAM's in total and all modules are presented in Visual Basic. Each module has its own form, which ensures ease and consistency of data entry.

RIVET MANUFACTURERS: The JSAMs advertised are applicable to joints using rivets manufactured by;

  1. Bollhoff Rivet Fastenings Ltd. email: brian.prout@bollhoff.co.uk
  2. Henrob Rivet Fastening systems Ltd email:howard@henrob.demon.co.uk
  3. Ariel Rivet Fastening systems Ltd
  4. Avdel Textron Fastening systems Ltd

PARAMETRIC TOOL
All the solutions present sufficient accuracy to offer the designer the capability of parametric and sensitivity analytical studies when designing joints. The JSAM's offer analytical solutions predicting failure strengths and failure modes of riveted, adhesively bonded and combined rivet/adhesively bonded Lap and T-Peel joints. JSAM analysis modules assist studies relating to;
Joint durability.
Joint durability at tempearture.
Crash Analysis supportive data.
Joint optimisation.
Rivet count reduction.


INDUSTRIES WHERE JSAMs MAY BE APPLICABLE.
These VB application Tools can be used by industries such as;
Automotive.
Aerospace.
Ship building.
Rail-Rolling stock.
Container.
Domestic utilities, eg washing machines, fridges.


JOINT VARIATION.
Virtually any variation of Joint/rivet/adhesive configuration may be quickly explored for strength and failure mode. Joint strength and mode failure are given in the results output box.


SOURCE AND VALIDATION.
Many of the analytical methods have been validated by test results and each solution has been derived from professional knowledge and referenced sources.

Key Benefits
Parametric/Sensitivity design studies.
Minimize the need for Coupon testing.
Visually shows joint failure modes.



AUTOMOTIVE:
Many automotive manufacturers are now seriously examining the production of lightweight vehicle concepts ( benefits of emissions and fuel performance ) using materials such as aluminium and composites materials such as carbon or glass fibre.

It is apparent that the most likely method of joining such materials is by the use of self-piercing rivets, adhesives or a combination of both. Other material options lending themselves to this cold-joining technique include, steel/plastic and aluminiun/steel.

WEIGHT/COST
A typical aluminium bodied family saloon car fastened together using rivets, is likely to contain between 4000 to 8000 steel rivets. Not only is an excess of rivets in the vehicle an unnecessary weight burden, but a higher rivet count per vehicle also requires more robotic assembly installations, with their inherent cost of installation and maintenance. Unit vehicle cost can then be very sensitive to influences of rivet numbers.

DESIGN.
During conceptual design of say aluminium vehicles, invariably the Designer or Stress Engineer will be faced with panel joint optimisation. Testing programs can provide joint failure data and Finite Element analysis is an excellent analytical/design tool. However, the number of materials and/or riveted joint/adhesive combinations required to obtain statistical usable joint test data can demand expensive and comprehensive testing programs. So it is not always possible for the vehicle Designer or Stress Engineer to obtain the latest or the appropriate joint strength data.



JSAMS
The use of JSAMs provide the Designer or Stress Engineer with quick and easy to use powerful Visual Basic tools to assess the strength and failure mode of virtually any variation of Joint/rivet/adhesive configuration. JSAMs offer the following; · Optimise any joint/rivet/adhesive configuration for either weight, strength and mode failure.#
· Joint geometry may be varied until the optimum joint strength is achieved.
· Determine joint failure strength and failure mode for existing joints. Helpful when trouble shooting, eg, trying to understand how joint geometry affects mode of failure.
· Failure modes displayed include; a) Bearing failure. b) Shear Failure. c) Net Tension Failure.
· Conduct Parametric and Optimisation studies relating to joint/rivet/adhesive geometric and material variations.

    · Rivet count minimisation studies.
    · Rivet type minimisation studies.
    · Calculation of joint width required to sustain specific loading.
    · Joint strength variation due to temperature variation.

There are also separate modules covering the above list in relation to temperature effects on the joints.


JOINT INPUT VARIABLE:
· The joint parameters that may be varied in the calculation input include;
· Joint width.
· Joint thickness.
· Unequal thickness adherends.
· Number of adherands. ( More than two can be used. )
· Joint overlap.
· Joint materials. Note: Top and bottom adherands may be of different materials.
· Youngs Modulus.
· Material strength.
· Rivet to edge distance.
· Rivet diameter.
· Number of rivets.
· Rivet materials.
· Adhesive strength.
· Adhesive shear modulus.
· Adhesive laid down thickness.
· Temperature.

VEHICLE DURABILITY.
Many of the JSAM Tools have been designed to support durability studies of joint strength, wether by rivet, adhesive or a combination of both fastening systems. Also, parametric studies can be examined For the same joints under temperature exposure.

VEHICLE CRASH ANALYSIS.
Use of such programs as DYNA crash analysis ( maybe for EURONCAP ) requires a parameter that sets the axial load of the rivet at joint failure. The DYNA analysis then enables the Designer to estimate the most likely zones of joint unzip on crashed vehicle structural members. A JSAM tool can calculate the axial rivet load value at joint failure.

VEHICLE FEA ANALYSIS.

This is a list of the Visual Basic Mathematical prediction Modules,( Incomplete) ;

  1. Joint Strength,
  2. Rivet axial load,
  3. Joint strength at temperature.