Drop Test Simulation and FEA for Consumer Products: How to Design Parts That Survive Real Use

Physical testing is still essential, but it is slow and expensive when it is used to search for problems rather than to confirm a design that already works. Simulation changes the order:

• Fix problems before tooling: changing a CAD model takes hours; changing a finished mould takes weeks and real money.
• Test more ideas, faster: compare wall thicknesses, rib layouts, materials and drop orientations in days, without building a prototype for each one.
• See why a part fails, not just that it fails: simulation shows stress, strain and contact everywhere in the part, including places a test camera cannot see.
• Fewer prototype rounds: use physical tests to confirm the final design, not to find the first failure.
• Fewer returns: products that survive real use cost far less to support after launch.

Drops are the most common way consumer products fail. A drop test simulation uses explicit dynamic FEA, the same method used for crash analysis, to reproduce the few milliseconds of an impact. We use the same explicit approach in our impact simulation on foam in Ansys Explicit Dynamics and our car bonnet impact and damage analysis.

• The product falls from a set height onto a rigid floor in the orientations that matter: flat on a face, on an edge and on a corner.
• You see where the housing cracks, whether screw bosses and clips survive, and whether parts separate or the battery door pops open.
• You can check what reaches the inside: how far the circuit board bends, how hard the battery and display are hit, and whether components touch.

Simulations usually follow the drop heights and orientations of the test you have to pass, such as IEC 60068-2-31 for equipment drops and topples, or ISTA procedures for packaged products, so the results map directly onto your test plan.

Good results depend on good inputs. Plastics behave differently at impact speeds (most get stiffer and stronger), so realistic material data, correct contact between parts and the mass of heavy internal components all matter.

Many failures happen during everyday use rather than in a drop: a handle that flexes too much, a hinge boss that cracks or a bracket that slowly creeps. Static FEA checks parts under the loads that users and assembly actually apply, as in our FEA of a nylon injection-moulded part.

Plastics need more care than metals:

• Their stress-strain behaviour is non-linear, and their strength drops as the temperature rises.
• Under a constant load they creep, which loosens press fits and screw bosses over time.
• Glass-filled grades are strongest along the direction the fibres line up during moulding, so the same part can be weaker in another direction.

FEA also backs up the classic design rules: keep wall thickness uniform, make ribs thinner than the wall they support (typically around half to two-thirds of it) to avoid sink marks, add generous radii at internal corners, and support bosses with ribs instead of making them thick.

It is also a quick way to choose the right plastic. In our FEA material comparison of polycarbonate, PA11, PA12 and carbon-filled PA12, the same part was checked in each candidate grade before one was chosen.

Snap fits are cheap and quick to assemble, but they are easy to get wrong. A clip that bends too far cracks during assembly; one that is too stiff makes the product hard to assemble or service.

• FEA predicts the strain in the clip as it deflects and compares it with the allowable strain that material suppliers publish for snap-fit design.
• Contact analysis gives the assembly and disassembly forces, so you know how the snap will feel in the hand.
• For clips and hinges that are opened many times, a fatigue check predicts how long they will last.

Living hinges, usually moulded in polypropylene, are checked the same way, with the strain concentrated in the thin hinge section.

Chargers, speakers, smart-home devices, power tools and kitchen appliances all have electronics that get hot inside a closed plastic box. CFD with conjugate heat transfer models the airflow and the heat moving through the solid parts together.

• Find hot spots and check that components stay within their rated temperatures.
• Check the surface temperatures users can touch. Product safety standards such as IEC 62368-1 limit how hot accessible surfaces may get.
• Compare vent positions, fans and heat sinks before committing to a design.

The temperatures can then feed an FEA model to check for warping or stress in plastic parts close to hot components. For examples of this kind of work, see our CFD airflow analysis of a fan heater and our CFD study of a duct designed to improve cooling.

Products with motors, fans or pumps vibrate, and products that travel in cars and trucks are shaken for hours.

• Modal analysis finds the natural frequencies, so they can be kept away from motor speeds and the product does not rattle or resonate.
• Fatigue analysis estimates the life of parts that are loaded again and again: hinges, buttons, handles and springs.
• Random vibration analysis checks products and their mounts against transport and in-vehicle vibration.

A product that survives a drop on its own can still arrive broken if the packaging is wrong, while over-packaging wastes material and shipping cost.

• Drop simulation of the packed product shows how much shock reaches the product through the cushioning.
• Foam thickness and density, inserts and box design can be compared to protect the product with the least material.
• The drops can follow the sequence of the transport test the product has to pass.

• Concept stage: compare layouts, materials and wall thicknesses quickly, before details are fixed.
• Before tooling: the most valuable moment. Check drops, snap fits and bosses while the steel has not been cut.
• After a failed test or a field return: find the root cause and prove the fix before you test again.

Simulation does not replace your final certification tests, but it makes them far more likely to pass the first time. A common approach is to simulate the design, fix the weak spots, run one physical test and use it to confirm the model. After that, the model can be trusted to check later design changes quickly. We also check our methods against published experiments, as in our CFD of a backward-facing step validated against experimental data.

To give you an accurate quote and get started quickly, send us as much of the following as you have:

• 3D CAD files (STEP, IGES, Parasolid or native files). If you only have sketches or drawings, our 3D CAD team can build the model.
• The material grade of each part, for example PC/ABS or 30% glass-filled PA66, with datasheets if you have them.
• The situations to check: drop heights and orientations, user forces, temperatures or vibration.
• The standard or test plan the product has to pass.
• The mass and position of heavy internal parts such as batteries, motors and circuit boards.
• Any test results or failed samples, which help us confirm the model.