Stress and Design

TLG is unique among aerospace engineering service providers in that we fully support the entire iterative aircraft design cycle. Our Stress Analysts and Designers work collaboratively with the TLG Loads, Flutter, Aerodynamic Performance and Aerodynamic Engineers to assure product requirements are achieved as well as meet certification requirements. TLG’s team of Stress Analysts and Designers can begin with general arrangement layouts and trade studies and mature the design through preliminary sizing to the release of manufacturing definition, either 2D-Paper drawings or 3D Model Based Definition (MBD) files and support production and post-production activities.


Development of aerospace products is a true collaborative endeavor which requires many disciplines to be successful. TLG’s in-house Stress and Design capability complements the Loads, Flutter and Aero-performance groups. When working as an integrated team, the Stress and Design disciplines enables TLG to conduct a complete load loop design cycle. This concurrent team approach can provide overall shorter development schedules, higher levels of optimization with lower development risk, all with direct DER involvement.

TLG recognizes that many Customers have their own internal design department. In these cases, TLG can provide our stress and design resources as an off-site extension to the Customer’s existing capabilities to provide efficient coordination of development issues. Many of our Customers utilize TLG’s Stress and Design staff to focus on secondary structure or systems development while their in-house team stays focused on their primary areas of expertise. Either way, TLG Stress and Design capabilities will help assure the Customers product meets performance, schedule, and cost objectives.


TLG employs a variety of classical methods and numerical simulation tools to analyze and size structural components. When it is deemed beneficial to build a Finite Element Model, TLG’s meshing tools are the recently released and industry leading MSC Apex™, MSC PATRAN, Star CCM+. TLG can run a full range of simulations, including: Linear Static, Modal, Buckling, Frequency Response, Thermal, Implicit and Explicit Nonlinear. TLG employs large computing clusters to support time intensive simulations and analysis. TLGs ability to support multiple parallel solutions is another capability that is available to alleviate bottlenecks on customer projects and preserve program schedules.

It takes much more than a FEM to assure aircraft components meet requirements. Primary structure may require Fatigue and Damage Tolerance (F&DT) analysis. Addressing criteria such as Failsafe or Safe-life early in the development cycle can significantly alter the test and certification approach. The influence of installed systems on the surrounding structure and critical flight controls surfaces need to be acknowledge and accounted for, like rotor burst and small fragment damage. Critical crack growth lengths needs to be calculated to achieve desired maintenance intervals. TLG staff are experienced with both the F&DT analysis tools and continued airworthiness documents that category 23 and 25 aircraft require.

In additional to analyzing primary and secondary aircraft structure, TLG has recently completed and currently support many aerospace related tooling programs. These span from thermal and stress analysis of high pressure Resin Transfer Molds (TRM), transitional autoclave and oven thermal cycle analysis, to specialized large scale aircraft shipping fixtures used to transport whole fuselage and wing assemblies by air. TLG understands that many of these tools do not require the fidelity of certified airframe component and that many of these job require a very quick completion schedule.

Documentation and validation of analysis is important and necessary, particularly when certification by a Regulatory Authority is sought. To this end, TLG has developed stress analysis templates that can be used to generate Certification level Reports. TLG can provide support for test instrumentation definition and test plan creation and review when validation of the structure is required. TLG can fully support the common axiom: Certification by analysis, validate by test.

The TLG Stress team is prepared to work with the Customer to generate an analysis plan that will assure a program is successful.


TLG utilizes industry standard CATIA V5 as our core modeling and design tool. Use of CATIA’s advanced surfacing features enables TLG designers to assure lofted surfaces comply with the aerodynamicist’s criteria. From these “clean” surfaces the design team can mature the product concept to the level of completion desired by the Customer.

When the Customer requests, TLG can release production level datasets or more traditional 2D drawings of detail components, assemblies and installations. As production authority, these datasets will include the functional tolerance and annotation to clearly convey the manufacturing requirements to the shop floor. Geometric Dimensioning and Tolerances (GD&T) will comply with ASME Y14.5-2009 standard.


A program is the most successful when all stake-holders are involved in the design process. TLG fully endorses the Integrated Product Team (IPT) approach for development programs. We openly solicit input from the Procurement, Quality and manufacturing teams to assure the product is producible using leading industry standard materials, processes and procedures. TLG can be an integral part of your existing IPT.