In crash simulations, bolt connections are generally modeled as simplified analogous models (Beams or Connectors). More efficient modelling at a favourable cost is required. In a project TECOSIM develop an automatic bolt generator for crash simulations in ABAQUS.

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Development of an automatic bolt generator for crash simulations in
ABAQUS
Abstract of project results

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Bolt connections in vehicle construction
July 2016 Development of an automatic bolt generator for crash simulations in ABAQUS2
1. INITIAL SITUATION
§ Along with welded joints, bolt connections are the most
frequently used means of fastening
§ A medium-class vehicle contains about 250 safety-relevant bolt
connections
§ In crash simulations, bolt connections are generally modeled as
simplified analogous models (Beams or Connectors)
§ Requirements for more exact prediction capacity in complete
vehicle simulations and occupant safety are increasing
§ More efficient modelling at a favourable cost is required
Boltfunctions

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Main objectives
July 2016 Development of an automatic bolt generator for crash simulations in ABAQUS3
2. TASK
§ Programming of a ANSA-GUI (graphical user interface) to generate solid bolts automatically
§ Produce and validate material cards for bolts in different property classes
The breaking force should match theoretical values or test data as best as possible
- Bolt sizes studied: M8, M10, M12, M14, M16, M18
- Property classes studied: 6.8, 8.8, 10.9, 12.9
- Type of thread pitch: metric
- On material properties: Elastic deformation
Plastic deformation
Necking until fracture
- Criteria for assessing the bolt model quality: ultimate tensile strength, ultimate shear strength

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Possible bolt variants
July 2016 Development of an automatic bolt generator for crash simulations in ABAQUS4
3. PROJECT DESCRIPTION / IMPLEMENTATION
Four variants for bolt modelling:
(A) Bolt with nut and shank
(B) Bolt with nut, but no shank
(C) Bolt with no nut, but with shank
(D) Bolt with no nut and no shank

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GUI for bolts with nuts
July 2016 Development of an automatic bolt generator for crash simulations in ABAQUS5
3. PROJECT DESCRIPTION / IMPLEMENTATION
§ Section 1: selection of bolt size,
strength class,
type of bolt connection
§ Section 2: definition of bolt geometry
§ Section 3: parameters for pre-stressing
§ Section 4: generate and position bolts (bolt is
automatically numbered, contacts with flange
generated, prepared for output as seperate include)

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Result
July 2016 Development of an automatic bolt generator for crash simulations in ABAQUS6
4. RESULTS AND PROSPECTS
§ A tool has been developed to generate high-quality models for crash load cases more easily and more quickly than before
§ The bolts, including their pre-loading calculation, can now be generated and positioned easily on a simple GUI (graphical user
interface) with just three clicks
§ The bolts are pre-loaded using a connector, so that a realistic grip is achieved
§ A material model whith failure criteria was also generated and validated which takes many standard bolt sizes and strength classes
into account
§ The model is based on theoretical values taken from bolt tables
§ The bolts show a comparable, realistic result in test load cases; no larger deviations occur until higher deformation rates are reached

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Contact
July 2016 Development of an automatic bolt generator for crash simulations in ABAQUS7
TECOSIM Technische Simulation GmbH
Wolfgang Woost
General Manager
Wilhelm-Wagenfeld-Str. 3
D-80807 Munich
Tel +49 (0)89 552 679-17
Fax +49 (0)89 552 679-22
Mail w.woost@de.tecosim.com
www.tecosim.com