FEA Structural Simulation | Drop Test · Small-ball Impact · Structural Strength Simulation Verification

WHY SENRMOLD CAE

Why Senrui's simulation is closer to real mass production

Simulation is not hard; the hard part is making simulation results match what the physical drop test shows. Our advantage comes from two decades of injection-molding production data and test benchmarking.

Plastic Constitutive Material Library

We built our own engineering-plastic material library (ABS/PC/PC+ABS/PP/PA+GF/POM/TPU, etc.), including elastoplastic curves, failure strain, and strain-rate correlation—rather than fudging with a single elastic modulus; this is the first watershed for whether drop simulation is accurate.

Mold flow → FEA anisotropic mapping

Injection-molded part strength is not isotropic. We map Moldflow's fiber-orientation and residual-stress results onto the finite-element model, so that simulation results for glass-fiber-reinforced parts (PA+GF) closely match the actual fracture location.

Closed Loop with the Same Structural Design Team

Simulation engineers and structural engineers are on the same team; when an issue is found, they don't just hand over a report but directly give a concrete structural-change plan: where to add ribs, how large an R, how long to revise the clip—all clarified at once.

Test Benchmarking & Empirical Correction

With our own drop and impact test conditions, and repeated simulation-vs-measurement benchmarking, we have accumulated correction experience (contact parameters, damping, failure criteria) to avoid the embarrassment of 'simulation passed but the physical part cracked'.

Load Case Library Covering Major Standards

Drop postures (6 faces + 12 edges + 8 corners), ball-drop specs, and press/torsion conditions are built into a library per IEC/GB/ASTM/ISTA and customer enterprise standards, so projects can call them directly without defining from scratch.

Simulation Reports Ready for External Use

The report includes model description, material-parameter sources, mesh and boundary conditions, contour results, criterion evaluation, and improvement suggestions; the format can align with the customer's template and be submitted directly to the customer's quality department or end customer for review.

SIMULATION CAPABILITY

Core Simulation Capabilities

Centered on the mechanical reliability of plastic structural parts and complete products, providing complete analysis capabilities from explicit impact to implicit strength, from modal to fatigue.

Full-Device Drop Simulation

Drop Test

At heights such as 1.0/1.2/1.5 m, simulate 26 free-fall orientations across 6 faces + 12 edges + 8 corners to identify cracking, snap-fit breakage, and internal-component impact.

Operating conditions covered26 postures

Explicit DynamicsMulti-Pose Scanning

CAE Verification

Get a Solution

Ball Drop Impact

Ball Drop

Steel / stainless-steel ball free-fall impact on panels, lenses, screens, and housings, assessing local denting, crack initiation, and penetration risk, benchmarked against ASTM D5628.

Impact Energy AccuracyHigh

Ball Drop ImpactLocal Failure

Impact Simulation

Get a Solution

Static Strength & Stiffness

Press / Torsion

Key force, panel pressing, whole-unit torsion, and three-point bending, evaluating whether deformation, yield risk, and stiffness meet feel and structural requirements.

Deformation prediction accuracy±10%

Implicit StaticStiffness Evaluation

Static Analysis

Get a Solution

Snap-Fit Insertion/Extraction & Preload

Assembly Load Cases

Snap-fit insertion / retention force, screw preload stress, interference-fit assembly stress—judging fatigue and permanent deformation after repeated insertion/extraction.

Force prediction accuracy±15%

Contact NonlinearityInsertion/Extraction Force

Contact Analysis

Get a Solution

Vibration & Fatigue Durability

Modal / Random

Modal analysis identifies the resonance frequency; random vibration (PSD) and sine sweep evaluate the durability under shipping and in-vehicle conditions, predicting fatigue life and weak points.

Resonance IdentificationFull Band

Modal AnalysisRandom Vibration

Fatigue Durability

Get a Solution

Thermal-Structural & Warpage Coupling

Multiphysics

Combining mold-flow warpage results and temperature fields to evaluate thermal deformation, assembly stress superposition and dimensional stability under high-low temperature cycling.

Deformation PredictionExcellent

Warpage CouplingTemperature Cycling

Multiphysics

Get a Solution

SIMULATION WORKFLOW

Simulation Workflow

A ten-step standardized process, with each step documented and reviewable: model source, material origin, mesh quality, boundary conditions, and criteria are all written into the report.

Requirements & Load Case Definition

Standard / Height / Orientation

Geometry Cleanup & Simplification

Suppress Non-Load-Bearing Details

Material Constitutive Calibration

Elastoplastic + Failure

Meshing

Quality & Convergence Control

Contact & Boundary Conditions

Friction / Constraints

Solving & Computation

Explicit / Implicit

Post-Processing Contour Plots

Stress / Strain / Displacement

Criterion Evaluation

Pass / Risk / Failure

Improvement Plan

Structural Optimization Suggestions

Test Correlation

Measured-Data Review & Correction

LOAD CASE & CRITERIA

Typical Conditions & Evaluation Criteria

Simulation conclusions must rest on clear criteria—not "looks okay," but quantified strain, deformation, and safety margin.

Condition Category	Typical Parameter Settings	Reference Standards	Evaluation Criteria
Whole-Unit Free Drop	Height 1.0 / 1.2 / 1.5 m; concrete or steel-plate rigid floor; 6 faces + 12 edges + 8 corners	IEC 60068-2-31、GB/T 2423.8	No through-crack in the housing; equivalent plastic strain < 70% of material failure strain; snaps do not disengage; no contact interference of internal components.
Packaging & Shipping Drop	Grade drop height by weight; packed / bare unit comparison; cumulative multiple drops.	ISTA 1A/2A、GB/T 4857.5	Product functions normally; no obvious appearance deformation; cushion energy absorption meets design expectation.
Small-Ball Impact (Drop Ball)	Steel ball Φ13–Φ50 mm, mass 8 g–500 g; drop height 0.3–1.3 m; impact at center and corner	ASTM D5628、GB/T 2611	No crack or penetration at impact point; no shattering of transparent parts; dent depth within acceptance range.
Panel / Button Pressing	Static pressure 30–200 N; indenter Φ6–Φ12 mm or finger-press model	Customer enterprise standard / IEC 60950 relevant clauses	Max displacement < design clearance; stress < yield strength / safety factor 1.5
Whole-Unit Torsion & Bending	Torque 0.5–5 N·m; three-point bending span per product length	Customer Enterprise Standard	No permanent deformation; structural stress < yield strength; screen under no abnormal load
Clip Insertion / Removal	Insertion/withdrawal speed 10–100 mm/min; 10–50 cycles	Customer Enterprise Standard	Insertion force within acceptable assembly range; retention force > design threshold; no residual deformation or fracture after cycling
Modal & Random Vibration	Frequency 5–2000 Hz; PSD spectrum per vehicle / transport conditions.	GB/T 2423.10、ISO 16750-3	First natural frequency avoids the excitation main frequency; stress below fatigue limit; predicted life meets requirement.
High-Low Temperature Cycling	−40 °C to 85 °C cycling; combined with Moldflow warp initial stress.	GB/T 2423.22	Dimensional change within tolerance; assembly stress does not cause cracking; seal compression still meets spec.

Stress / Strain Contour

Low → High

Criterion 1

Plastic Strain Margin

Ratio of equivalent plastic strain to material failure strain < 0.7, retaining 30% safety margin against batch and process variation.

Criterion 2

Deformation & Clearance

Max displacement must be below design clearance so the screen, battery, and PCB are not compressed at the instant of drop.

Criterion 3

Connection Integrity

Clips, bosses, and weld lines do not disengage or pull out during impact; retention remains above the design threshold.

Criterion 4

Functional Availability

After impact, key travel, open/close feel, and seal compression remain within acceptance limits; product function is unaffected.

MATERIAL MODEL

Plastic Material Constitutive Library

The accuracy of drop simulation is 80% determined by the material model. We maintain elastoplastic curves, failure strain, and rate-dependent parameters by material family, and correct them with physical measurements.

ABS

Toughness · General

Elastic-plastic + strain-rate dependent; commonly used for housings and structural parts; drop performance mainly absorbs energy via plastic deformation, so weld-line location needs attention.

PC

High toughness · Impact resistant

Excellent impact resistance but notch-sensitive; simulation focuses on max principal strain at R corners and stress-concentration zones.

PC+ABS

Balanced · Mainstream

Combining toughness and rigidity, it is the main material for consumer electronics and automotive parts; constitutive curves are calibrated by grade according to different PC contents.

PP

Low Modulus · Large Deformation

Significant energy absorption under large deformation requires large-deformation nonlinear solving; watch permanent deformation and hinge fatigue.

PA+GF

High Stiffness · Anisotropy

Glass-fiber reinforced with pronounced mechanical anisotropy; combined with mold-flow fiber orientation mapping, it significantly improves the accuracy of fracture location prediction.

POM

Wear-resistant · High rigidity

Commonly used for gears and sliding parts; watch fatigue and creep; low impact toughness requires focus on sharp-corner checks.

TPU / TPE

Hyperelastic · Cushioning

Described with hyperelastic constitutive models (Mooney-Rivlin / Ogden) to evaluate cushioning energy absorption and sealing compression behavior.

PMMA / PC Lenses

Transparent · Brittle

Brittle-failure criterion (max principal stress); drop-ball impact breakage risk is the core concern.

Metal Insert / Sheet Metal

Elastoplastic · Hardening

Nuts, brackets, shields, etc. use metal elastoplastic models to evaluate contact stress with plastic and pull-out risk.

Material data sources: official supplier datasheets & Senrui's proprietary material database (covering density, drying and molding parameters for 13 resin families and 90+ in-house factory grades). For key projects, measured tensile／impact specimen calibration curves can be arranged to further increase simulation confidence.View the Material Database →

SOLVER & SCALE

Solver & Computation Scale

Explicit and implicit dual solver system, with workstation computing power, balancing the high nonlinearity of drop impact and the accuracy needs of static strength analysis.

Abaqus

Explicit / Implicit

Explicit＋Standard

Ansys

Structure / Modal

Mechanical

LS-DYNA

Impact Specialization

High-Speed Collision

1 Million+

Mesh Size

Hexahedral / Tetrahedral Hybrid

Moldflow

Process Coupling

Warpage / Fiber Orientation

3–7

Report Lead Time (Working Days)

Depends on Number of Conditions

Simulation Analysis Report (PDF)

Includes model description, material parameters and sources, mesh statistics, boundary conditions, contour results, criteria evaluation, and conclusions; can be submitted externally directly.

Structural Improvement List

Specific improvement actions sorted by priority: ribs / R-fillets / wall thickness / snap-fit dimensions / material substitution, with expected improvement ranges.

Contour Plots & Animation

Stress / strain / displacement contour plots; drop-process animation (GIF / MP4) for intuitive communication at design reviews.

Comparison Analysis Table

Quantitative comparison of before/after solutions (max strain, max displacement, safety margin) to support design decisions.

Model File (Optional)

Deliver solver model files such as inp / cdb per customer requirements, for customer's internal recalculation or secondary analysis.

Test Correlation Recommendations

Provide a recommended physical verification plan (drop posture priority, measurement point layout) so limited physical prototypes are used where they matter most.

CASE STUDIES

Typical Simulation Verification Case

Below are representative simulation project types (examples, not specific customers), showing practical applications of drop, impact, and strength verification.

Consumer Electronics Example

Handheld terminal 1.5m drop optimization

26-posture scanning located excessive plastic strain at the clip root of the upper shell during a corner drop. By increasing the root R to 0.8 mm and adding triangular ribs, the maximum plastic strain dropped 42%, and the physical drop test passed on the first try.

26 posturesstrain −42%first-pass

Panel Drop-Ball Example

Panel steel-ball impact (ASTM D5628)

A Φ38mm steel ball dropped from 1.0m impacts the center of the decorative panel; the original PMMA lens exceeded its fracture strength in max principal stress. After switching to a PC lens + back-side annular support ribs, stress dropped into the safe zone and the ball-drop test showed no cracks.

Ball Drop ImpactMaterial SubstitutionNo Cracking

In-Vehicle Part Example

In-Vehicle Bracket Random Vibration Durability

The PA+GF bracket's first mode is close to the vehicle body's dominant excitation frequency, and its root fatigue life under random vibration is insufficient. Adjusting the rib orientation raised the first frequency by 38%, improving predicted life by an order of magnitude.

Modal analysisfrequency +38%fatigue improved

Medical Device Example

Handheld Medical Device Pressing & Drop

The medical PC enclosure was verified for both 150 N panel pressing and a 1.2 m drop. Through local thickening and internal support-column design, the press displacement dropped from 1.4 mm to 0.5 mm while remaining crack-free on drop.

Press strengthdisplacement −64%dual conditions

0

Cumulative Simulation Projects

0

Drop Posture Condition Library

0

Simulation–Measured Consistency Rate

0

Average Mold-Trial Count Reduction

CORE METRICS

Core Metrics · Quantified Capability

The value of simulation is not in pretty contour plots, but in opening the mold one less time, dropping one less batch of samples, and revising the structure one less time. Below are typical project statistics.

90%

Simulation–Measured Consistency Rate

Pass / Failure Judgment Match

85%

Failure Location Prediction Accuracy

Fracture-Point Localization Consistency

40%

Mold-Trial / Prototyping Count Reduction

Issues Shifted Earlier to Simulation

94%

Improvement Plan Effectiveness

Pass Test After Suggested Revision

96%

Report Approved on First Submission

Customer Review with No Rework

90%

Simulation–Measured Consistency Rate

96%

Report On-Time Delivery Rate

85%

Failure Location Hit Rate

Note: the above are statistical ranges for typical projects. Simulation is an engineering prediction tool whose accuracy is affected by material batch, molding process, assembly state and actual use conditions; for critical safety parts, physical testing is recommended as the final acceptance basis, while simulation is used for option screening and risk pre-assessment.

ANALYSIS TYPE

Analysis Type Comparison & Selection

Different problems need different solvers. Click a tag to quickly decide which analysis your product needs.

Whole-machine drop simulation (explicit dynamics)

Suitable for evaluating a product's overall drop resistance. Short solve time (millisecond-level physical time), but demands fine mesh and contact settings; the most common verification method in consumer electronics.

When to Use

Handheld/portable products, uncertain housing strength, complex clip structures, or customers explicitly requiring drop tests.

Inputs Required

Complete-unit 3D model (including internal main components), material grades, drop height and orientation requirements, component weight distribution.

Output Conclusions

Ranking of max plastic strain/displacement per configuration, failure-risk-point localization, structural-improvement priority.

Small-Ball Drop Impact (Local Impact)

For local areas rather than the whole device: cracking and denting of panels, lenses, and screen covers under concentrated impact. The model can be localized, with low computation cost and fast iteration.

When to Use

Large flat / transparent parts, panels requiring ball-drop test, or switching material from PMMA to PC needs evaluation.

Inputs Required

Digital model of impacted zone, steel-ball spec and drop height, back support structure, material brittleness parameters.

Output Conclusions

Max principal stress/strain, crack-initiation location, max allowable drop height, back-side support-rib optimization.

Static Strength & Stiffness (Implicit Static)

Evaluates deformation and yield under long-term or slowly applied loads. Stable computation and intuitive results, suitable for key feel, panel stiffness, and assembly preload assessment.

Comparison Dimensions	Static Strength Analysis (Implicit)	Drop Impact Analysis (Explicit)
Loading Rate	Slow / Quasi-Static	Millisecond-Scale High-Speed Impact
Key Results	Max Displacement, Yield Risk, Stiffness	Plastic Strain, Failure, Component Interference
Material Model	Elastic / Elastoplastic Sufficient	Must Include Strain Rate & Failure Criterion
Typical Conditions	Pressing, Torsion, Preload, Stacking	Drop, Drop-Ball, Collision
Computation Cost	Low, Hour-Level	Higher; multiple postures need paralleling
Applicable Criteria	Stress < Yield / Safety Factor	strain < failure strain × 0.7

Vibration & Fatigue Durability

First use modal analysis to find natural frequencies, then random vibration or sine sweep to evaluate long-term durability, and finally fatigue solving to predict life.

When to Use

In-vehicle / transport environment, product with motor or fan, customer requires vibration endurance testing.

Inputs Required

Full-machine model and counterweight, support and fixation method, excitation spectrum (PSD/sweep) or duty description.

Output Conclusions

Natural frequencies and mode shapes per order, stress response, fatigue-life prediction, structural frequency adjustment plan.

Mold-flow coupled analysis (process–mechanics linkage)

Bring the real consequences of injection molding into mechanical analysis: weld-line position, fiber orientation, residual stress, and initial warped shape—all as initial conditions for the mechanical analysis.

When to Use

Glass-fiber reinforced parts, large thin-wall parts, weld line landing in the load-bearing zone, or large deviation between simulation and measured results.

Inputs Required

3D models, material grades, gate scheme, and process parameters (or we run the mold-flow analysis in parallel).

Output Conclusions

Mechanical results including anisotropy and residual stress, weld-line weakening impact assessment, and gate position improvement suggestions.

FAILURE MODE & FIX

Common Failure Modes & Countermeasures

The table below summarizes the most frequent failure modes in drop and strength simulations, and our standard structural improvement methods.

Failure Mode	Simulation Behavior	Root Cause Analysis	Improvement Countermeasures
Housing Corner Cracking	Local plastic strain exceeds failure value at corner drop	Corner is a stress-concentration zone; R too small or wall thickness abrupt.	Increase outer/inner R, locally thicken corners or add triangular ribs; switch to high-toughness material if necessary.
Clip Ejection / Fracture	Strain concentration at clip root; contact force instantly exceeds retention.	Cantilever too short/thick, no R at root, undercut too small.	Adjust length-to-thickness ratio to 5–10, root R ≥ 0.3 mm, recalculate undercut amount and retention force, increase snap-fit count to distribute load
Boss Pull-Out / Root Crack	Principal stress at stud root exceeds yield; circumferential cracks appear.	Stud wall too thin, no transition R at base, preload too high.	Add R and ribs at the base; keep wall at 60% of main wall; standardize assembly torque.
Upper/Lower Shell Separation	Joint gap instantaneously opens beyond design value	Fixing-point spacing too large; clips only, no screw assistance.	Reduce fixed-point spacing (≤60 mm), add screws at critical points, add guide posts to limit relative displacement
Lens / Transparent-Part Cracking	Max principal stress exceeds brittle material fracture strength	Brittle materials like PMMA + lack of back support.	Switch to PC, add ring/mesh support ribs on the back, add cushion strips at edges to disperse impact.
PCB & Components Under Compression	At impact, housing displacement exceeds clearance gap	Insufficient clearance, inadequate housing stiffness	Increase clearance, add housing ribs to raise stiffness, add cushion foam around components.
Weld-Line Cracking	Fracture location differs from the max-stress site in simulation; it lies on the weld line.	Gate scheme places weld line on load-bearing area	Adjust gate position or increase gate count, or structurally move the load path away from the weld line.
Glass-Fiber Part Fracture Along Flow	Isotropic Model Underestimates Fracture Risk	PA+GF shows mechanical anisotropy; strength perpendicular to flow is markedly lower.	Run mold-flow coupled mapping of fiber orientation; adjust gate so fiber direction aligns with main load direction.
Vibration Fatigue Fracture	First-mode frequency falls within the excitation band; root stress cycles exceed fatigue limit.	Insufficient structural stiffness or unreasonable mass distribution	Adjust rib direction to raise natural frequency, add fixing points, locally thicken to lower stress amplitude.

Engineering Interpretation of Simulation Results

FEA simulation is an engineering prediction tool used for concept screening, early risk identification and improvement direction; its absolute values are affected by material batches, molding process, assembly state, and contact and friction conditions. Senrui states model assumptions and parameter sources explicitly in its reports, and recommends benchmarking against physical measurements. For critical structures involving personal safety or mandatory certification, physical testing and third-party test reports should serve as the final acceptance criteria.

FAQ

Questions you may have about structural simulation cooperation.

What do I need to provide for a drop simulation?+

A minimum of three things is needed: ① the 3D model of the complete product (STEP / X_T / native formats all acceptable, including simplified bodies of major internal components such as PCB, battery and display); ② material grade and supplier for each part; ③ test requirements (drop height, orientation, floor type, acceptance criteria). If the weight distribution of components is unknown, we can assign values based on experience and note the assumption in the report.

How far do simulation results differ from actual drop-test results?+

With reliable material parameters and reasonable boundary conditions, our drop simulation agrees with physical tests on pass/fail determination at about 90% and locates the failure position at about 85%. Absolute strain values typically deviate by 10–25%, so we adopt a criterion that retains a 30% safety margin rather than drawing conclusions right at the critical value.

How long is the simulation cycle? Can it be expedited?+

A single scenario (e.g., panel ball-drop) usually takes 3 business days; a full-unit 26-orientation drop scan takes 5–7 business days; complex projects involving mold-flow coupling or fatigue analysis take 7–12 business days. For urgent projects, a quick version covering 6 faces + 4 most dangerous corners (about 2 days) can first provide preliminary conclusions, after which the full scenarios are completed.

My product is still in the structural design stage; when is the best time to engage simulation? +

The best timing is after the 3D structure is basically formed and the part-splitting scheme is settled, but before the 2D drawings are issued and the mold is made. At this point, structural changes cost the least. We usually recommend two rounds: one before finalizing the structure to find problems, and one after improvement to confirm. If the mold is already made, simulation can still locate the cause of mold-trial cracking and guide mold modification.

Is it OK to do simulation only, without structural design and molding?+

Absolutely—simulation is a fully independent service. You provide the digital model and requirements; we deliver the analysis report and improvement suggestions, with no obligation for subsequent mold making. Of course, if both structural design and simulation are done by us, the improvement suggestions can be applied directly to the digital model, greatly speeding up iteration.

Can the report be shown directly to my end customers?+

Yes. Reports are written to engineering standards and include model description, source of material parameters, mesh statistics, boundary conditions, result contour plots, criteria evaluation, and conclusions; format and language (Chinese/English) can be adjusted to the customer's template. Many clients directly use our reports as design validation material submitted to their end customers.

Drop-test the product before mold opening

The cost of one simulation is far below that of one mold modification. Send us your 3D model and testing requirements, and we'll provide a simulation plan proposal, condition list, and quote within 48 hours.

Submit Simulation Request View Structure Design Service

FEA Structural SimulationDrop · Ball Drop · Strength Virtual Verification

Why Senrui's simulation is closer to real mass production

Plastic Constitutive Material Library

Mold flow → FEA anisotropic mapping

Closed Loop with the Same Structural Design Team

Test Benchmarking & Empirical Correction

Load Case Library Covering Major Standards

Simulation Reports Ready for External Use

Core Simulation Capabilities

Full-Device Drop Simulation

Ball Drop Impact

Static Strength & Stiffness

Snap-Fit Insertion/Extraction & Preload

Vibration & Fatigue Durability

Thermal-Structural & Warpage Coupling

Simulation Workflow

Requirements & Load Case Definition

Geometry Cleanup & Simplification

Material Constitutive Calibration

Meshing

Contact & Boundary Conditions

Solving & Computation

Post-Processing Contour Plots

Criterion Evaluation

Improvement Plan

Test Correlation

Typical Conditions & Evaluation Criteria

Plastic Strain Margin

Deformation & Clearance

Connection Integrity

Functional Availability

Plastic Material Constitutive Library

Solver & Computation Scale

Simulation Analysis Report (PDF)

Structural Improvement List

Contour Plots & Animation

Comparison Analysis Table

Model File (Optional)

Test Correlation Recommendations

Typical Simulation Verification Case

Handheld terminal 1.5m drop optimization

Panel steel-ball impact (ASTM D5628)

In-Vehicle Bracket Random Vibration Durability

Handheld Medical Device Pressing & Drop

Core Metrics · Quantified Capability

Analysis Type Comparison & Selection

Whole-machine drop simulation (explicit dynamics)

When to Use

Inputs Required

Output Conclusions

Small-Ball Drop Impact (Local Impact)

When to Use

Inputs Required

Output Conclusions

Static Strength & Stiffness (Implicit Static)

Vibration & Fatigue Durability

When to Use

Inputs Required

Output Conclusions

Mold-flow coupled analysis (process–mechanics linkage)

When to Use

Inputs Required

Output Conclusions

Common Failure Modes & Countermeasures

Engineering Interpretation of Simulation Results

FAQ

Drop-test the product before mold opening

Processes & Services

Quick Links

Contact Information

FEA Structural Simulation
Drop · Ball Drop · Strength Virtual Verification