Fatigue Analysis of Welded Structures Using the Finite Element Method

FEA & CFD Based Simulation Design Analysis Virtual prototyping MultiObjective Optimization

Enteknograte use advanced Numerical simulation software and methods to simulate the welding behavior in real service load condition and estimate its life. The Seam Weld and Spot Weld fatigue simulation enables the fatigue analysis of joints including different type of welding such as fillet, overlap, spot welds in thin sheets and laser welded joints.

Spot Weld, Seam Weld Vibration fatigue analysis in time frequency domain

Fatigue simulation is used for many types of durability analysis:

  • High-cycle (S-N) Stress-Life fatigue
  • Low-cycle (E-N) Strain-Life fatigue
  • Neuber and other plasticity correction methods
  • Crack initiation and growth using Paris
  • “Hot spot” identification
  • Deformation and damage analysis
  • Virtual strain gauge for test-analysis correlation
  • Damage accumulation using Palmgren-Miner
  • Fatigue of Rotating Systems
  • Vibration fatigue using random loading
  • Spot and seam weld analysis
  • Classic “weld classification” approach to fatigue
  • Material failure predictions
  • Non-proportional, multiaxial stress states
  • Multiple simultaneous loads and multiple events allowed
  • Safety factor analyses
Fatigue fe-safe abaqus ansys caefatigue ncode RSW Seam Welding Simulation Finite element FEA Simufact welding ESI sysweld

Based on what we want to Design and Analysis, Stress, Strain or temperature from finite element (FE) software such as ANSYS, ABAQUS, NASTRAN, LS-Dyna, MSC Marc etc used. This FEA (Finite Element Analysis) must contain correspond simulation step detail based on what we want to do in Fatigue Simulation. Enteknograte engineers use different methodology for each specific industrial and research fields and multiphysics. MSC CAEFatigue, Ansys Ncode, Simulia FE-Safe and FEMFAT are our fatigue analysis tools. With the Fatigue analysis, we can:

  •  Correct for mean stress and surface finish effects
  •  Determine a scale or fatigue concentration factor required to achieve a target life
  •  Review damage histograms to determine which load cycles were most damaging
  •  Output damage time histories to show exactly when the damage occurred

Industry is putting increasing pressure on manufacturers to use less material to deliver lightweight but stronger components, less warranty and recall costs and all in less time. Traditional methods of over-engineering components and expensive, open-ended test-redesign-test programs are not meeting the needs of the modern engineering company. For welded joints and welded structures, the prediction of failure locations and the calculation of fatigue lives are notoriously complex and difficult tasks, which can often result in poor correlation with test data.

Durability and Fatigue Application highlights in different industry

  •  Fatigue Simulation in Aerospace: Wings, panels, engine blades, rivets, bondings, valves, nacelles, interior component, etc.
  • Durability and Fatigue in Automotive: Chassis, rivets, bolts, wheels, connecting rods, full body systems, door, seat, dashboard, interior component, drivetrain component, underhood, oil cooler bracket, front-end carrier,Fatigue behavior of vehicle-mounted medical equipment as it interacts with the suspension dynamics of the vehicle and the road load, etc.
  • Fatigue Application in Biomedical: Prosthesis, Fatigue properties of medical implants, etc.
  • Durability and Fatigue in Energy sector: Pipes, vessel, valves, fan blade, pump body, Effects of the complex conditions seen in wind turbines such as vibration, the effects of rotating components and different wind states, etc.
  • Fatigue Simulation in Electronics: Connectors, clips, electronic racks and housing assemblies,etc.
  • Fatigue Simulation in Marine and offshore: Ship hulls and staructures fatigue analysis of welded joints using FEA models, etc.



Creep and Creep-Fatigue Interactions

considering Creep-Fatigue interaction in high temperature simulations identifies whether fatigue and/or creep are the dominant damaging mechanisms, thus allowing re-design to focus on the relevant damage mechanisms and significantly reduce pre-service component testing.

Vibration Fatigue Finite Element Simulation: Time & Frequency Domain

Structural vibration can be a source for many product related problems; it can cause fatigue and durability problems as well as adverse reactions to the user or bystanders in the form of undesirable vibrations that can be felt or heard. As well, undesired structural vibrations can prevent products from operating as required and potentially becoming a safety concern. The Vibration Fatigue simulation predict fatigue in the frequency domain and it is more realistic and efficient than time-domain analysis for many applications with random loading such as wind and wave loads.

Integrated Artificial Intelligence (AI) & Machine Learning - Deep Learning with CFD & FEA Simulation

Machine learning is a method of data analysis that automates analytical model building. It is a branch of Artificial Intelligence based on the idea that systems can learn from data, identify patterns and make decisions with minimal human intervention. With Artificial Intelligence (AI) applications in CAE, that is Mechanical Engineering and FEA and CFD Simulations as design tools, our CAE engineers evaluate the possible changes (and limits) coming from Machine learning, whether Deep Learning (DL), or Support vector machine (SVM) or even Genetic algorithms to specify definitive influence in some optimization problems and the solution of complex systems.

Finite Element Analysis of Durability and Fatigue Life

Vibration Fatigue, Creep, Welded Structures Fatigue, Elastomer and Composite Fatigue with Ansys Ncode, Simulia FE-Safe, MSC CAEFatigue, FEMFAT
Durability often dominates development agendas, and empirical evaluation is by its nature time-consuming and costly. Simulation provides a strategic approach to managing risk and cost by enabling design concepts or design changes to be studied before investment in physical evaluation. The industry-leading fatigue Simulation technology such as Simulia FE-SAFE, Ansys Ncode Design Life and FEMFAT used to calculate fatigue life of multiaxial, welds, short-fibre composite, vibration, crack growth, thermo-mechanical fatigue.

Elastomer Materials Fatigue Finite Element Analysis​

Developers of rubber materials, components and systems increasingly rely on simulation as a routine means to address design issues. For metallic components, solutions for fatigue analysis from FEA have existed commercially for many years and have become an essential part of maturing and qualifying design concepts in many industrial sectors. Using modern multiaxial strain based fatigue methods enable us to simulate the fatigue analysis of elastomer materials and Rubber.

Composites Fatigue Finite Element Simulation

The structural durability of a component is one of the most expensive attributes to test, thus one of the most appealing for CAE. Fatigue modeling of chopped and continuous fiber polymer composites is challenging due to their anisotropic, heterogeneous and viscous material properties as well as their process-dependent microstructure. For simulation of high cycle fatigue (HCF) of fiber reinforced composites we use FEA tools Like VirtualLab Durability, nCode DesignLife , MSC CAEFatigue and FE-SAFE.

Resistance Spot Welding: Finite Element Simulation of RSW

Resistance Spot Welding is a pressure welding process during which the sheets are pressed together locally with the help of fitted copper electrode welding guns. The electrical current between the weld guns causes a heating and melting of the joining partners, creating a small circular welded area between them.The standard approach in a RSW model contains fully coupled electrical, thermal, metallurgical and mechanical steps, so the heat generation is calculated due to Joule’s heating coming from electrical current and resistivity between components.

Finite Element Simulation of Arc Welding

Arc welding processes (SMAW, GMAW [MIG], GTAW [TIG], SAW, …) are of the highest economic importance due to their flexible application and relatively low equipment costs for both robotic and/ or manually controlled joining. Due to a high melting rate and a high gap-bridging ability these processes are found most notably, in steel plants, power stations and shipbuilding.

Pressure Welding FEA Simulation: Friction welding, Resistance welding, Friction spot welding

Pressure welding is a group of diffrent joining processes which have all in common that the components are joined by applying heat and pressure. The heat can either be generated by an electrical current flow (resistance welding) or by friction (friction welding).

Finite Element Simulation of Brazing

Brazing is a thermal joining process which connects metal components with melted filler material. The filler usually has lower melting point compared to components. Main advantages of brazing lies in relatively low heat input and the capability to create a joint of considerable strength and durability.

Finite Element Simulation of Heat Treatment

In principle, there are two kinds of heat treatment processes: processes resulting in a thorough change of the microstructure and processes that result in merely changing regions close to the surface of the component. Examples of the former would be thermal processes, such as annealing and hardening. Examples of the latter, thermochemical processes, would be diffusion and coating processes, such as carburization, case hardening, nitrating, boriding.

Finite Element Simulation of Laser Beam / Electron Beam Welding

Laser Beam welding is a thermal joining process, in which a component is heated and welded by a laser beam. It is a high-end process for application cases requiring the highest degree of precision. A huge advantage of laser beam welding lies in the relatively narrow heat affected zone. Electron Beam welding is a thermal joining process, in which a component is heated and welded by electron beam.

Metal Forming Simulation

Sheet Metal Forming, Hot Forging, Cold Forming, Open Die Forging, Roll Forming, Extrusion and Heat Treatment with Ansys, Abaqus, LS-Dyna and Simufact
Using advanced Metal Forming Simulation methodology and FEA tools such as Ansys, Simufact Forming, Autoform, FTI Forming, Ls-dyna and Abaqus for any bulk material forming deformation, combining with experience and development have made Enteknograte the most reliable consultant partner for large material deformation simulation. Metal Forming Simulation include Springback Compensation, Surface Defects, Cost Estimation and Phase Transformation in Sheet Metal, Hot Forge, Rolling, Extrusion, Open Die Forging and Heat Treatment Finite Element Analysis.

Thermal Stress and Fatigue Simulation: Coupled CFD and Finite Element Approach

Enteknograte’s Engineering Team provides a comprehensive Steady-State and Transient CFD Thermal Analysis & Design services using MSC Cradle, Siemens Star-ccm+, OpenFoam and Ansys Fluent Flow Simulation. CFD Thermal Analysis extends the capability of FEA thermal analysis with MSC Nastran, Abaqus and LS-Dyna by replacing the simplistic convection boundary conditions with direct calculations of the heat transfer coefficients based on the fluid flow properties and is often referred to a conjugate heat transfer analysis.

Multibody Dynamics

Robots Dynamics, Control Systems, Advanced Machinery, Full Vehicle MBD and NVH
Multibody dynamic analysis is important because product design frequently requires an understanding of how multiple moving parts interact with each other and their environment. From automobiles and aircraft to washing machines and assembly lines - moving parts generate loads that are often difficult to predict. Complex mechanical assemblies present design challenges that require a dynamic system-level analysis to be met. Accurate modeling can require representations of various types of components, like electronic controls systems and compliant parts and connections, as well as complicated physical phenomena like vibration, friction and noise.

Finite Element Simulation of Crash Test and Crashworthiness with LS-Dyna, Abaqus and PAM-CRASH

Crashworthiness focuses on occupant protection to reduce the number of fatal and serious injuries. This research is responsible for developing and upgrading test procedures for evaluating motor vehicle safety. Crashworthiness research encompasses new and improved vehicle design, safety countermeasures and equipment to enhance occupant safety. Finite Element Analysis (FEA) has been the trend in virtual crash design over the last decade. The predictive capabilities of FEA allow engineers to fully understand a crash event in a virtual environment, thus limiting the number of physical tests that need to be executed and thus saving costs.

Additive Manufacturing and 3D Printing

FEA Based Design and Optimization with Simufact, Abaqus, ANSYS and MSC Apex for powder bed fusion (PBF), directed energy deposition (DED) and binder jetting processes
With additive manufacturing, the design is not constrained by traditional manufacturing requirements and specific number of design parameters. Nonparametric optimization with new technologies such as Artificial Intelligence in coupled with Finite Element method, can be used to produce functional designs with the least amount of material. Additive manufacturing simulations are key in assessing a finished part’s quality. Here at Eneteknograte, dependent of the problem detail, we use advanced tools such as MSC Apex Generative Design, Simufact Additive, Digimat, Abaqus and Ansys.

Hydrodynamics CFD simulation, Coupled with FEA for FSI Analysis of Marine and offshore structures

Transient Resistance, Propulsion, Sea-Keeping and Maneuvering Simulation, Cavitation, Vibration and Fatigue
Hydrodynamics is a common application of CFD and a main core of Enteknograte expertise for ship, boat, yacht, marine and offshore structures simulation based design. Coupling Hydrodynamic CFD Simulation in Ansys Fluent, Siemens Star-ccm+ and MSC Cradle with structural finite element solver such as Abaqus and Ansys, enable us to Simulate most complicated industrial problem such as Cavitation, Vibration and Fatigue induced by hydrodynamics fluctuation, Transient Resistance, Propulsion, Sea-Keeping and Maneuvering Simulation, considering two way FSI (Fluid Structure Interaction) coupling technology.

Acoustics and Vibration: FEA and CFD for AeroAcoustics, VibroAcoustics and NVH Analysis

Noise and vibration analysis is becoming increasingly important in virtually every industry. The need to reduce noise and vibration can arise because of government legislation, new lightweight constructions, use of lower cost materials, fatigue failure or increased competitive pressure. With deep knowledge in FEA, CFD and Acoustic simulation, advanced Acoustic solvers and numerical methods used by Enteknograte engineers to solve acoustics, vibro-acoustics, and aero-acoustics problems in automotive manufacturers and suppliers, aerospace companies, shipbuilding industries and consumer product manufacturers.

Heat Transfer and Thermal Analysis: Fluid-Structure Interaction with Coupled CFD and Finite Element Based Simulation

We analyze system-level thermal management of vehicle component, including underhood, underbody and brake systems, and design for heat shields, electronics cooling, HVAC, hybrid systems and human thermal comfort. Our Finite Element (LS-Dyna, Ansys, Abaqus) and CFD simulation (Siemens Start-ccm+, Ansys Fluent , Ansys CFX and OpenFoam) for heat transfer analysis, thermal management, and virtual test process can save time and money in the design and development process, while also improving the thermal comfort and overall quality of the final product.